Article

# Lactic acid bacteria – Potential for control of mould growth and mycotoxins: A review

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## Abstract

Most data dealing with the biopreservative activity of lactic acid bacteria (LAB) are focused on their antibacterial effects. Food spoilage by mould and the occurrence of their mycotoxins constitute a potential health hazard. Development of biological control should help improve the safety of products by controlling mycotoxin contamination. Data have actually shown that many LAB can inhibit mould growth and that some of them have the potential to interact with mycotoxins.This review summarizes these findings and demonstrates that LAB are promising biological agents for food safety.

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... Studies have also been conducted to elucidate the mechanism of mycotoxin removal by LAB (Dalié et al., 2010). It was demonstrated that binding is the main mechanism involved in fumonisin removal, with adhesion to LAB cell wall components occurring rather than covalent binding or metabolism (Dalié et al., 2010;Niderkorn et al., 2009;Zhao et al., 2016). ...
... Studies have also been conducted to elucidate the mechanism of mycotoxin removal by LAB (Dalié et al., 2010). It was demonstrated that binding is the main mechanism involved in fumonisin removal, with adhesion to LAB cell wall components occurring rather than covalent binding or metabolism (Dalié et al., 2010;Niderkorn et al., 2009;Zhao et al., 2016). Our preliminary results were in agreement with binding mechanism since fumonisin removal was observed in presence of both live and dead LAB (unpublished data). ...
... LAB strains are Gram positive and so their cell wall mainly consists of peptidoglycans, teichoic acids, proteins and polysaccharides (Chapot-Chartier and Kulakauskas, 2014;Delcour et al., 1999).It was reported that peptidoglycans of LAB cell wall are the main binding sites for fumonisins, their structural integrity is essential and their amino acid sequence plays an important role in the efficiency of the binding mechanism. TCA chains in fumonisins also are important components in the binding process (Dalié et al., 2010;Niderkorn et al., 2009;Zhao et al., 2016). ...
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3 Centre de coopération internationale en recherche agronomique pour le développement (CIRAD), UMR-Qualisud, TA B-95/16, Abstract: Maize, which contributes a large portion of the African diet and serves as the base substrate for many fermented cereal products,has been reported to be contaminated with fumonisins. This study aimed to evaluate in vitro the ability of predominant lactic acid bacteria (LAB) in African traditional fermented maize based foods (ogi and mahewu) to bind fumonisins B1 (FB1) and B2(FB2),as well as the stability of the complex at different pH and temperatures, in particular observed during ogi fermentation and under its storage conditions (time, temperature). The percentage of bound fumonisins was calculated after analysing the level of fumonisins not bound to LAB after a certain incubation time, by high performance liquid chromatography. The results revealed the ability of all tested LAB strains to bind both fumonisins, with binding efficiency varying between strains and higher for FB2. Binding of fumonisins increased with a decrease in pH from 6 to 4 (observed during ogi fermentation process) and from 4 to 2 (acidic pH in the stomach), and an increase in temperature (from 30°C to 37°C). The percentage of fumonisins (B1 and B2) bound to LAB at pH 4 decreased after 6 days of storage at 30°C for all LAB strains, except for L. plantarum (R1096) for which it increased. Lactobacillus species (L. plantarum and L. delbrueckii) were the most efficient in binding fumonisins (B1 and B2), whereas Pediococcus sp. the less efficient. Therefore, the Lactobacillus strains tested in this study can be recommended as potential starter cultures in African traditional fermented maize based foods to provide detoxifying and probiotic properties. 2
... The antimicrobial efficacy of LAB has previously been well documented in the literature as a result of the production of several compounds with low (<1000 Da) and high (>1000 Da; bacteriocins) molecular mass [40,44,45]. The most significant antimicrobial agent produced by LAB in the highest amounts is lactic acid [45]. ...
... Another hypothesis suggests that organic acids neutralise the electrochemical potential of the plasmic membrane, which increases its permeability and eventually leads to the death of the susceptible microorganism. These mechanisms were also demonstrated for acetic and propionic acids [44]. The importance of organic acid's role in the antimicrobial spectrum of LAB activity was confirmed in Gerez et al. [20] study, where the pH neutralisation treatment resulted in a loss of antimicrobial activity. ...
... Proteinaceous antifungal compounds, the release of reuterin and hydroxy fatty acids may also be responsible for antimicrobial efficacy of LAB [59]. Other possible mode of action our treatment work is competition for nutrients [44]. Our suggestion is that the effectiveness of LAB as a biocontrol agent against potato pathogens is the result of the synergistic action of the described mechanisms. ...
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Biological control offers an alternative to chemical pesticides, which are inconsistent with the global trend of “going green”. Biological control includes various approaches, from natural predators to biologically produced molecules. This article focuses on the selection of lactic acid bacteria (LAB) as biological control agents against potato pathogens. The scope included evaluating the antimicrobial activity of 100 LAB strains against ten phytopatogens (Pectobacterium carotovorum, Streptomyces scabiei, Fusarium oxysporum, Fusarium sambucinum, Alternaria solani, Alternaria, tenuissima, Alternaria alternata, Phoma exigua, Rhizoctonia solani, Colletotrichum coccodes) by cross-streak plate method. HPLC determined the metabolic profiles for the most active LAB strains, and lactic acid, acetic acid, propionic acid and ethanol were found in the largest quantities. The strain Lactiplantibacillus plantarum KB2 LAB 03 was finally selected and cultured on supplemented acid whey. After the selection in laboratory tests, the strain KB2 LAB 03 was assessed in situ on seed potatoes against phytopathogens. The test showed a 40–90% reduction of eight potato pathogens infestation; only F. sambucinum and F. oxysporum were not inhibited at all. L. plantarum KB2 LAB 03 was proposed as the potential biocontrol agent for the potato protection against phytopathogens.
... In addition to lowering pH, some LAB species/strains possess antibacterial properties resulting from a combination of factors, including competitive growth and the production of a variety of antibacterial compounds [132]. Antibacterial compounds produced by LAB include various organic acids, such as lactic acid, acetic acid, formic acid, and propionic acid, as well as such other compounds as diacetyl, acetoin, hydrogen peroxide, reuterin, and bacteriocins [133][134][135][136][137][138][139]. ...
... Therefore, the risk of mycotoxins in cheese increases when toxigenic fungi are allowed to grow during production and storage [148]. Filamentous fungi belonging to the genera Aspergillus, Fusarium, and Penicillium can grow on the cheese surface and produce mycotoxins that are highly toxic [133,138,150,[156][157][158]. Some mycotoxins are present only in the fungus, while most are excreted in food [159]. ...
... Aflatoxins are considered one of the most important and well-known classes of mycotoxins in food [159,160]. These compounds have numerous and diverse toxic properties, including carcinogenic, teratogenic, mutagenic, nephrotoxic, hepatotoxic, neurotoxic, immunosuppressive, and estrogenic effects, even when ingested at low concentrations [133,135,148,160]. ...
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Traditional cheeses produced from raw milk exhibit a complex microbiota, characterized by a sequence of different microorganisms from milk coagulation and throughout maturation. Lactic acid bacteria (LAB) play an essential role in traditional cheese making, either as starter cultures that cause the rapid acidification of milk or as secondary microbiota that play an important role during cheese ripening. The enzymes produced by such dynamic LAB communities in raw milk are crucial, since they support proteolysis and lipolysis as chief drivers of flavor and texture of cheese. Recently, several LAB species have been characterized and used as probiotics that successfully promote human health. This review highlights the latest trends encompassing LAB acting in traditional raw milk cheeses (from cow, sheep, and goat milk), and their potential as probiotics and producers of bioactive compounds with health-promoting effects.
... Mycotoxins are secondary metabolites generated by fungi during food spoilage and can endanger the safety of foodstuffs (Blagojev et al. 2012). Various classes of mycotoxins namely aflatoxins, fumonisins, ochratoxins, patulin, trichothecenes and zearalenone might be present in different foodstuff (Ahlberg, Joutsjoki, and Korhonen 2015;Dalié, Deschamps, and Richard-Forget 2010). Mycotoxins have carcinogenic, teratogenic, mutagenic, hepatotoxic and immunotoxic effects and therefore, their presence in foods is of great concern (Dalié, Deschamps, and Richard-Forget 2010;Hussein and Brasel 2001). ...
... Various classes of mycotoxins namely aflatoxins, fumonisins, ochratoxins, patulin, trichothecenes and zearalenone might be present in different foodstuff (Ahlberg, Joutsjoki, and Korhonen 2015;Dalié, Deschamps, and Richard-Forget 2010). Mycotoxins have carcinogenic, teratogenic, mutagenic, hepatotoxic and immunotoxic effects and therefore, their presence in foods is of great concern (Dalié, Deschamps, and Richard-Forget 2010;Hussein and Brasel 2001). Although good agricultural practices (GAP), pre-harvest, harvest and post-harvest management are considered as the most efficient approaches in inhibition of mold growth and toxin formation in raw materials and plants, mycotoxins contamination is inevitable. ...
... Numerous investigations have shown that 3-hydroxy fatty acids have antifungal action, which results from the agents' detergent-like properties that change the target organisms' cellular membrane structure (Sjögren et al., 2003;Dalié et al., 2010). Cyclic dipeptides are substances that can damage cell membrane structure, interfere with intracellular pH homeostasis, and inhibit essential metabolic processes which prevents A. flavus from growing (Dal Bello et al., 2007). ...
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This study was conducted in the laboratories of the Departments of Plant Protection and Animal Production at the College of Agriculture and Forestry / University of Mosul, and the Pharmacognosy laboratory of the College of Pharmacy / University of Mosul for the period from 3/9/2020 to 4/5/2022.The aims at identifying fungi contaminating local maize samples in grain stores (Al-Hawija, Al- Hamdaniya and Tikrit) and the morphological diagnosis of these fungi, including A. flavus. It confirms the diagnosis of the fungus using primers specific to Polymerase chain reaction (PCR) technology. It also determines the susceptibility of isolates of A. flavus in the production of aflatoxin B1(AFB1) and the identification of the most productive isolate of the toxin using High-performance liquid chromatography (HPLC).The growth and sporulation of A. flavus' were examined in vitro using C1, C2 furanocoumarins, Lactobacillus plantarum, a toxin-binding preparation (Anpro), and CuSO4. In maize grains contaminated with A. flavus under storage conditions, the effectiveness of C1, C2 compounds, L. plantarum, Anpro, and CuSO4 on inhibition of growth and sporulation as well as AFB1 production was evaluated. In vivo, quail birds that were fed with a food contaminated with AFB1 were given the aforementioned treatments, and the effects on several blood and biochemical parameters of the birds were examined.
... Lactic acid bacteria play a key role in food fermentations where they not only contribute to the development of the desired sensory properties in the final product but also to their microbiological safety [7,23] . The antimicrobial effect of lactic acid bacteria is mainly related to the production of lactic and acetic acids as well as propionic acids, sorbic acids, benzoic acids, hydrogen peroxide, diacetyl, CO 2 , acetaldehyde [6] , ethanol, phenolic and proteinaceous compounds [8] , organic acids and short chain fatty acids is one of the functional properties used to characterize probiotics [9,10] ; Also, some strains are able to synthesize antimicrobial substances-reuterin D-isomers of amino acids and bacteriocins [27] . Therefore, the present study aimed at isolation and identification of lactococcal cultures exhibiting antimicrobial activity against common food borne pathogens. ...
... La transplantation fécale chez l'humain a également montré que l'ajout de microorganismes permettait de diminuer la présence ou la toxicité de pathogènes comme Clostridium difficile (Baktash et al. 2018). Toujours dans le domaine de la santé, l'ajout de bactéries lactiques dans des consortia semble empêcher le développement de champignons unicellulaires mycotoxinogènes voire détruit leurs toxines (Dalié et al. 2010). Ces quelques exemples illustrent le fait que les interactions entre microorganismes au sein d'un consortium peuvent changer la fonction macroscopique de l'écosystème. ...
Thesis
Les écosystèmes microbiens sont présents sur toute la surface du globe. On découvre de plus en plus leur rôle dans de nombreux environnements, réalisant tout autant de fonctions. Les cultures mixtes interviennent ainsi dans les cycles biogéochimiques, les cycles du carbone ou de l'azote, la fabrication de boissons ou d'aliments, les caries voire un « deuxième cerveau » dans l'intestin humain ! Si l'étude des microorganismes s'est souvent faite isolée dans un milieu artificiel, comprendre une bactérie sans son environnement ne permet pas de comprendre son activité réelle. Récemment, a été mis en évidence que certaines bactéries pouvaient interagir entre elles en s'échangeant des électrons. Ainsi la bactérie fermentaire Clostridium pasteurianum a pu être observée récupérer des électrons de la bactérie électroactive Geobacter sulfurreducens. Comme conséquence, la bactérie fermentaire a profondément modifié son métabolisme fermentaire. L'objectif de cette thèse a été de comprendre par quel mécanisme C. pasteurianum pouvait recevoir des électrons de son environnement et par quel mécanisme cette souche bactérienne modifiait son profil métabolique dans ce cas.Pour cela, C. pasteurianum a été cultivé au contact d'une électrode polarisée ou avec G. sulfurreducens et l'influence des paramètres opératoires sur le transfert d'électrons et le profil métabolique a été étudiée. Puis, un séquençage des ARN de C. pasteurianum a été réalisé afin de comprendre moléculairement les tenants et aboutissants de l'interaction entre C. pasteurianum et G. sulfurreducens.En termes de résultats, aucun transfert d'électrons entre C. pasteurianum et une électrode n'a pu être assurément détecté. Il semble bien y avoir une interaction entre C. pasteurianum et G. sulfurreducens, celle-ci dépendant notamment des états physiologiques des deux bactéries. Toutefois, il apparaît que le transfert d'électrons ne soit pas la cause directe du changement métabolique de C. pasteurianum. Les cobamides ont été proposées comme molécules candidates produites par G. sulfurreducens modifiant le métabolisme de la bactérie fermentaire. Bien que non avéré avec certitude, le transfert d'électrons pourrait être, du côté de C. pasteurianum, assuré par une polyferrédoxine à flavines transmembranaire, et ne compter que pour très peu dans le changement métabolique observé.Ces résultats, bien qu'ayant besoin d'expériences complémentaires de validation, permettent de mieux comprendre les écosystèmes microbiens et de proposer des pistes de contrôle métabolique de procédés de fermentation.
... Zygosaccharomyces can provide essential vitamins or carbon and nitrogen sources for Lactobacillus, while Lactobacillus can provide the preferred energy substrate lactic acid for non-lactose fermentation yeast (Mayo, Rodríguez, Vázquez, & Flórez, 2021;Ponomarova et al., 2017). At the same time, Lactobacillus can inhibit the growth of other microorganisms by producing organic acids, antibiotics and competing for nutrients (Dalié, Deschamps, & Richard-Forget, 2010). The study found that the interaction network between microorganisms, like the human social network, although there are many groups, only a few are linked or highly correlated (Perez-Garcia, Lear, & Singhal, 2016). ...
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Zao Chili (ZC) is a traditional fermented pepper, which plays an important role in Chinese cooking. The aim of this study was to elucidate the effect of Lactipllantbacillus plantarum 5-1 on the physicochemical properties, metabolite and microbiota profiling of ZC. The physicochemical factors changed regularly with the fermentation time. In the microbial communities, Lactobacillus, Weissella, Enterobacter, Gibberella, Fusarium, Zygosaccharomyces and Pichia were the dominant genera. 7 kinds of organic acids were detected in the whole fermentation process of ZC, but only 5 kinds changed significantly. Based on the OPLS-DA model with VIP > 1 and ANOVA with P
... A total of 42 VOCs were identified in the doughs at T0 (Figure 3a), including ac alcohols (8), aldehydes (15), alkanes (3), esters (5), ketones (7), and terpenes (2). At a g level, the major compounds were alcohols and aldehydes. ...
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... The use of antagonistic and harmless microorganisms to prevent or decrease the growth of Aspergillus species and subsequently to reduce aflatoxin production is one of the most important methods of biological food preservation (3). In this regard, lactic acid bacteria and yeasts play a key role (4). Detoxification and biological uptake of mycotoxins by Saccharomyces cerevisiae has already been shown. ...
... There was no significant difference in brightness and redness between LSCK and HSCK (p > 0.05), while the yellowness value of LSCK was significantly higher than that of HSCK (p < 0.05), which might be due to the changed kohlrabi tissue structure caused by moisture migration during high-salt fermentation [23]. On the other hand, microbes generate acid substances such as organic acids by utilizing reducing sugars and proteins in fermentation systems during kohlrabi fermentation and thereby the pH of the fermentation system dropped [24]. In the present study, the pH value, reducing sugar, and protein contents of LSCK were significantly higher than those of HSCK (p < 0.05) and the total acid content of LSCK was significantly lower than that of HSCK (p < 0.05), which was inconsistent with Mi's study [25], that could be owing to the low temperature inhibiting the growth of lactic acid bacteria and related enzyme activities. ...
Article
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To explore the effect of low-temperature and low-salt fermentation on the volatile flavor substances of Chinese kohlrabi, low-temperature and low-salt fermented Chinese kohlrabi (LSCK) and traditional high-salt fermented Chinese kohlrabi (HSCK) were produced. The physicochemical and texture properties of the two kinds of Chinese kohlrabies were evaluated. Headspace gas chromatography-ion mobility spectrometry (GC-IMS) and electronic nose (E-nose) were used to analyze the volatile flavor substances of the kohlrabi. The results showed that the total acid content significantly decreased (p < 0.05), while protein and reducing sugar contents significantly increased (p < 0.05) by low-temperature and low-salt fermentation. A total of 114 volatile flavor substances were identified. The alcohol, ketone, pyrazine, ether, and nitrile contents in LSCK were significantly higher than those in HSCK (p < 0.05). Moreover, the unpleasant flavor from the 3-methylbutyric acid formation was effectively depressed in LSCK. The principal component analysis (PCA) and orthogonal partial least squares discrimination analysis (OPLS-DA) models established by multivariate statistical analysis significantly distinguished the two types of kohlrabies. Multivariate statistical analysis suggested that 16 volatile flavor substances with VIP >1, including tetrahydrothiophene, ethyl 3-(methylthio)propanoate, 3-methylbutyric acid, hexanenitrile, and 3-methyl-3-buten-1-ol, could be used as potential biomarkers for identifying LSCK and HSCK. The E-nose analysis further demonstrated that there was a significant difference in overall flavor between the LSCK and HSCK. The present study provides support for the development of green processing technology and new low-salt Chinese kohlrabi products.
... LAB have been identified as biocontrol agents against a wide range of mycotoxigenic fungi. Generally their biocontrol activity was ascribed to the production of low molecular weight compounds, such as organic acids, phenolic compounds, hydroxy fatty acids, hydrogen peroxide, reuterin and proteinaceous compounds (Blagojev et al., 2012;Dalié et al., 2010;Sadiq et al., 2019). LAB strains are also able to produce proteolytic enzymes that can play an important role in the biodegradation and detoxification process of mycotoxins (Abrunhosa et al., 2014;Wang & Xie, 2020). ...
... A. flavus was more sensitive than A. parasiticus to the cell-free supernatant and its dilution. The antifungal activity of lactobacilli may be due to their ability to produce fungistatic bacteriocin-like substance, phenyllactic acid and 4-hydroxyphenyllactic acid, short-chain fatty acids and low-molecular weight substances, such as benzoic acid, methylhydantoin, mevalonolactone and cyclo (Gly-L-Leu) as reported by (Corsetti et al., 1998;Niku et al., 1999;Okkers et al., 1999;Lavermicocca et al., 2003;Dalié et al., 2010). The inhibition effect of L. plantarum ATCC 14917 was similar to the inhibition effect that shown by L. plantarum YO which was able to inhibit the vegetative and sporulative growth of all aflatoxin producing Aspergilli (Ghonaimy et al., 2007). ...
... Organic acid application causes acidic medium which affect the fungal cell membrane as well as the enzymes activity which responsible for degrading the substrate (Kristiansen and Sinclair 1979). Furthermore, Dalie et al. (2010) reported that changing the electrochemical properties of the plasma membrane and increasing its permeability caused by organic acids action. Increasing the diffusion of acid across the plasmic membraneisand cytoplasm is resulted due to the reduction of pH at greater concentration of protons. ...
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Mild brown and black spot diseases symptoms were detected on citrus varieties, Valencia and Navel fruits during season 2018 in some citrus orchards at North Egypt. Collected diseased fruit samples revealed isolation of Alternaria alternata and Phyllosticta citricarpa (McAlpine) van der Aa. Some organic acids, salts and Saccharomyces cerevisiae were evaluated against the diseases incidents in vitro and in vivo. Complete growth inhibition was recorded for fungi tested at 2g/L of salicylic acid, Potassium dihydrogen phosphate, Tri-Sodium polyphosphate and 2.5 g/L of S. cerevisiae. All pre-harvest treated Valencia trees, inoculated fruits revealed no diseases symptoms up to 10 days of storage period. Meanwhile, S. cerevisiae and salicylic acid treatments had extended protective effect up to 20 days. Control strategy through spraying Valencia orange trees with yeast or some organic acids and salts as pre-harvest approaches should be taken in consideration especially these diseases began to occur in North region of Egypt.
... Organic adsorbents includemicroorganisms (such as yeasts and lactic acid bacteria [LAB]) and yeast cell walls. The detoxification potential of LAB might be related to the degradation through its metabolism or bacterial cell wall compounds (Dalié et al., 2010). Detoxification of DON by eight LAB isolated from wheat products and kefir seed was studied and the results revealed all of the bacteria have the detoxification potential of DON (Franco et al., 2011). ...
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Mycotoxins contamination occurring in dairy cow's diet is responsible for devastating effects on livestock health. Among different strategies, using organic adsorbents is a promising approach to reduce the toxicity of mycotoxins. This study investigated the effects of an organic adsorbent containing Lactobacillus brevis TD4, Lactobacillus paracasei TD3, and Saccharomyces cerevisiae cell wall on milk production, somatic cell count, blood parameters (white blood cell [WBC], lymphocyte [LYM], neutrophil, basophil, monocyte, eosinophil, red blood cell, haemoglobin, haematocrit, mean corpuscular volume, mean corpuscular haemoglobin) and liver function (alanine transaminase [ALT], gamma-glutamyl transferase [GGT], aspartate transaminase [AST], alkaline phosphatase [ALP], urea, total protein, albumin) in dairy cows fed a naturally contaminated diet with Zearalenone and Deoxynivalenol. The amounts of mycotoxins Zearalenone (ZEA) and Deoxynivalenol (DON) in feed ingredients were measured using the HPLC method. Ten Holstein dairy cows received organic adsorbents daily in their diets for four weeks. Milk and blood samples were taken from cows before the start of feeding adsorbent (CTRL), during the feeding period (FP), and one week after removal of adsorbent from the diet (RP). Totally, the amount of measured ZEA and DON toxins in the diet were 389 and 1254.6 ppb, respectively. Feeding of organic adsorbent significantly increased milk production, total serum protein, and albumin compared to CTRL (P<0.01). Also, numerically lower somatic cell count in their milk and a significant decrease (P<0.01) in serum urea were resulted. Among examined blood parameters, the number of WBC and LYM significantly decreased (P<0.01) after feeding with the organic binder in comparison to the control period. Furthermore, except for a significant increase in the level of AST (P<0.05), the other liver function examined parameters were not affected. The consumption of feed containing low-cost organic adsorbent including Lactobacillus bacteria and yeast cell wall can improve the physical condition and health of dairy cows and reduce economic losses in livestock production.
... Acetic acids generally used as safe agents to preserve foods, these acids reduce cytoplasmic pH and stop metabolic activities. On the other hand, organic acids cause the death by the susceptible organisms act on the plasmic membrane by neutralizing its electrochemical potential and increasing its permeability [32,33]. Some mechanisms explained the inhibitory mode of organic acids resulting in pH decreasing, this may influence the growth by acidifying the cell, which will consume a great amount of energy to maintain the intracellular pH homeostasis [34]. ...
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Raw meat spoilage by yeasts is a significant problem that is a consequence of many yeast species growth in the product including Candida albicans. Candida albicans utilizes food components and are transformed into many metabolic end products leading to sensory, chemical and physical properties changes with especial reference to the health impacts on the consumer's health. Therefore, the current experimental study aimed to investigate the inhibitory effect of two vital food additives (Propionibacterium and acetic acid) at four different concentrations (0.5, 1.0, 2.5 and 5%) on C. albicans including recording their impact on the sensory characters of the treated chicken fillet samples in chilling conditions (4±1 O C): After physical and microbial examination for nine days of storage, results showed significant improvement in the sensory characters of the treated samples, especially with increasing the concentration of the tested additives when compared with the control untreated samples which was spoiled at the 9th day of inoculation. Regarding with the anti-C. albicans effect of the tested materials, in general, C. albicans showed higher reduction percent with increasing the concentration of the inoculated additives; furthermore, the treated samples with 2.5% and 5.0% acetic acid, after nine days of inoculation, showed more reduction in C. albicans counts (70.7% and 87.2%, respectively) than the treated samples with Propionibacterium of the same concentration (41.4 and 52.7%, respectively): Referring to the obtained results, Propionibacterium and acetic acid of the 2.5% and 5.0% concentration could be considered a good choice for preservation and enhancing quality of chilled chicken fillet, and may be recommended for its usage in chicken fillet preservation as safe and easy applied food additives.
... Furthermore, the recorded reduction in C. albicans can be referred to its ability to secrete bacteriocins, propanoic acid and vitamin B12 that have direct antifungal effects ( Acetic acid is typically utilized as secure food preservative; they lower the cytoplasmic pH and halt metabolic activities. However, organic acids operate on the plasmic membrane to kill sensitive organisms by neutralizing its electrical potential and increasing its permeability (Dalie et al., 2010 andShaltout et al., 2016). Some methods explain how organic acids' inhibitory mode causes pH to decrease, which may affect the development by acidifying the cell and requiring a lot of energy to maintain intracellular pH equilibrium (Pandey et al., 2016). ...
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Keywords The current experimental study aimed to investigate the inhibitory effects of two food additives (Propionibacterium and acetic acid) at four different concentrations (0.5, 1.0, 2.5 and 5%) on Candida albicans (C. albicans) including recording their impact on the sensory characteristics of the treated chicken fillet samples in chilling conditions (4±1 O C). After physical and microbial examination for nine days of storage, results showed significant improvement in the sensory characteristics of the treated samples, especially with increasing the concentration of the tested additives when compared with the control untreated samples, which were spoiled on the 9 th day of inoculation. Regarding the anti-C. albicans effect of the tested materials, in general, C. albicans showed a higher reduction percent with increasing the concentration of the inoculated additives; furthermore, the treated samples with 2.5% and 5.0% acetic acid, after nine days of inoculation, showed more reduction in C. albicans counts (70.7% and 87.2%) than the treated samples with Propionibacterium of the same concentration (41.4% and 52.7%), respectively. Referring to the obtained results, Propionibacterium and acetic acid (2.5% and 5.0%) can be considered good choices for preserving and enhancing the quality of chilled chicken fillets and may be recommended for their usage in chicken fillet preservation as safe and easily applied food additives.
... Furthermore, bacteriocins were produced to inhibit or kill food spoilage or pathogenic microorganisms in addition to pH (Thomas 2018). Antifungal or anti-mycotoxigenic compounds produced by LAB can inhibit fungal growth or absorb mycotoxins (Dalié et al. 2010). Therefore, LAB can be used as bio preservative for meat products (Barcenilla et al. 2022). ...
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Novia R, Ardiningsih P, Adhityawarman, Sarwiyati. 2022. Characteristics of Lactic Acid bacteria isolated from traditional fermented fish. Biodiversitas 23: 5662-5669. Lactic acid bacteria (LAB) are commonly involved in most food fermentation and contribute to the process’s quality and safety. The study investigates the characteristics of LAB isolated from buduk, pekasam, and pekasam ale-ale. Twelve colonies each sample were isolated and identified based on morphology and biochemical test. The pekasam ale-ale isolates were identified as Pediococcus sp. strain A1 and Pediococcus sp. strain A3; Enterococcus sp. strain A2 and Enterococcus sp. strain A4. The LAB in buduk were identified as Streptococcus sp. strain B1, Pediococcus sp. strain B2 and Pediococcus sp. strain B4, Enterococcus sp. strain B3. The pekasam isolates were identified as Pediococcus sp. strain P1, Streptococcus sp. strain P2 and Streptococcus sp. strain P4, Lactobacillus sp. strain P3. The LAB showed antimicrobial activities while Lactobacillus sp. strain P3 and Streptococcus sp. strain P4 could grow at pH 1. Two LAB including Enterococcus sp. strain A2 and Pediococcus sp. strain P1 showed amylase activity while Pediococcus sp. strain A3, Streptococcus sp. strain B1, Pediococcus sp. strain B2, Enterococcus sp. strain B3 showed protease activity. All LAB produced organic acids with varying concentrations at different incubation times. Furthermore, those isolated from various fish fermentations showed different genera and characteristics. Lactobacillus sp. strain P3 was the best to initiate food fermentation and a probiotic candidate based on their characteristics.
... lycopersici, a phytopathogenic fungus that causes disease in tomatoes. The efficacy of these malolactic LAB strains was very competitive when compared to the previous studies of L. plantarum isolated from different sources (Rouse et al., 2008;Daliéet al., 2010). It has also been shown that the plant-derived Weissella confusa and Pediococcus pentosaceous strains both have broad-range inhibitory action against fungal diseases of fruit crops. ...
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The microbial diseases cause significant damage in agriculture, resulting in major yield and quality losses. To control microbiological damage and promote plant growth, a number of chemical control agents such as pesticides, herbicides, and insecticides are available. However, the rising prevalence of chemical control agents has led to unintended consequences for agricultural quality, environmental devastation, and human health. Chemical agents are not naturally broken down by microbes and can be found in the soil and environment long after natural decomposition has occurred. As an alternative to chemical agents, biocontrol agents are employed to manage phytopathogens. Interest in lactic acid bacteria (LAB) research as another class of potentially useful bacteria against phytopathogens has increased in recent years. Due to the high level of biosafety, they possess and the processes they employ to stimulate plant growth, LAB is increasingly being recognized as a viable option. This paper will review the available information on the antagonistic and plant-promoting capabilities of LAB and its mechanisms of action as well as its limitation as BCA. This review aimed at underlining the benefits and inputs from LAB as potential alternatives to chemical usage in sustaining crop productivity.
... Lactic acid bacteria can produce organic acids and hydrogen peroxide, which can inhibit the growth of other strains (26,27). Both of them have been reported to act on the cytoplasmic membrane by neutralizing its electrochemical potential and increasing its permeability, resulting in bacteriostasis and ultimately death of susceptible bacteria (28). In this study, isolating and screening bacteriocin-producing strains from 2,000 plant-derived strains by agar well diffusion method with E. coli and S. aureus as indicator strains were conducted. ...
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In this study, screening bacteriocin-producing strains from 2,000 plant-derived strains by agar well diffusion method was conducted. The corresponding produced bacteriocin was purified and identified by Sephadex gel chromatography, reversed-phase high-performance liquid chromatography (RP-HPLC), and liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). Meanwhile, the biological characteristics of bacteriocin were investigated. The targeted strain W3-2 was obtained and identified as Lactobacillus plantarum by morphological observation and 16S rRNA gene sequence analysis. Correspondingly, a novel bacteriocin (named plantaricin W3-2) produced by L. plantarum W3-2 with a molecular weight of 618.26 Da, and an amino acid sequence of AVEEE was separated, purified by Sephadex gel chromatography and RP-HPLC, and identified by LC-MS/MS. Further characteristics analysis displayed that plantaricin W3-2 had good thermal, pH stability, and broad-spectrum antimicrobial ability. In conclusion, plantaricin W3-2 can be used as a new food preservative.
... Organic acids diffuse through the cytoplasmic membrane of pathogens in their hydrophobic form and then reduce intracellular pH and stop metabolic activities which generally restricts growth of pathogenic bacteria. Also, hydrogen peroxide, which is produced and accumulated by LAB in the presence of oxygen, has a toxic effect on bacterial pathogens, especially that they cannot produce catalase enzymes (Dalié et al. 2010;Reis et al. 2012). Also, LAB may overcome pathogens by pre-emptively colonizing plant tissues (Tsuda et al. 2016), which creates competition for nutrients and space, or by induction defense responses of hosts toward the pathogen (Konappa et al. 2016). ...
Article
Biological control has received increasing interest in recent decades as one of the alternatives to chemical pesticides in the field of plant disease control, especially after the increased awareness of the dangers of pesticides to the environment in general and human health in particular, and the emergence of resistance to pesticides in some causes. Biological control is defined as any conditions or procedures in which a particular organism or substances produced from a living organism are used to reduce infection with a particular pathogen. Plant growth promoting rhizobacteria (PGPR) are able to stimulate growth and resistance against plant diseases when they are able to have a positive effect on the plant health, and then demonstrate good competitive qualities and capabilities over existing rhizosphere communities. PGPR affects plant growth improvement by fixing atmospheric nitrogen, siderophore production dissolving insoluble phosphates, and releasing hormones. In this review, we tried to focus on the potential effects of PGPR as an effective and safe technique for plant disease resistance. PGPR play a major role in plant disease resistance through induced systemic resistance (ISR), antibiotics, hydrogen cyanide, Lytic enzyme, degradation of toxins, competition for nutrients, and parasitism.
... The pH value of the growth medium is another external factor to affect aflatoxin production (Dalié et al., 2010). During fungal growth in a specific medium, pH may vary to values of 4 to 5 depending on fungal metabolic activities (Moreau, 1979;Uthpala et al., 2021). ...
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Purpose: Coconut oil is one of the commonest and profusely used plant oils in Asian cuisine. Many studies are being carried out aiming at preventing/eliminating potential aflatoxin contamination of the oil or its products along the value chain. The present review analytically provides an overview of aflatoxin occurrence, contamination, detection, and decontamination of vegetable oils with special emphasis on coconut oil. Research Method: Findings and conclusions of studies related to aflatoxins, that are published in authentic sources were reviewed and presented in a chronological manner. Based on the information, current detection and decontamination methods for aflatoxins in edible plant oils were demonstrated. Findings: Complete decontamination of aflatoxins from edible oils seemed impossible, but reducing the accumulated concentrations below the permissible levels seemed possible. The use of chemical agents like alkalis, the most commonly practiced method on a commercial scale, adversely affects human health and the environment. UV irradiation is a promising physical decontamination method of oil with aflatoxins and combining UV irradiation with other potential methods such as the use of adsorbents showed an enhanced efficacy. However, further studies are required to ensure the effective and safe use of biological methods in aflatoxin-contaminated edible oils. Research Limitations: Research gaps in the application of biological decontamination methods in edible oils especially in coconut oil were found. Originality/ Value: This paper critically and aimfully analyzes the relevant information with a view to f ind gaps thereby showing new directions for applied research to assess nutritional, sensory, and quality attributes in the oils and value-added products, subjected to biological treatments.
... The results achieved in table (2) revealed that the incidence of yeast contamination in examined ready to eat chicken meat product samples were 0 (0%),15 ...
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The present investigation was designed to study the total mould and yeast counts and Aflatoxin residues in a total of 60 random samples of ready to eat chicken products which include Shawerma, smoked chicken breast, Pane and grilled chicken (15 of each) were collected from different localities under different sanitation levels at Cairo governorate.
... Furthermore, the recorded reduction in C. albicans can be referred to its ability to secrete bacteriocins, propanoic acid and vitamin B12 that have direct antifungal effects ( Acetic acid is typically utilized as secure food preservative; they lower the cytoplasmic pH and halt metabolic activities. However, organic acids operate on the plasmic membrane to kill sensitive organisms by neutralizing its electrical potential and increasing its permeability (Dalie et al., 2010 andShaltout et al., 2016). Some methods explain how organic acids' inhibitory mode causes pH to decrease, which may affect the development by acidifying the cell and requiring a lot of energy to maintain intracellular pH equilibrium (Pandey et al., 2016). ...
Article
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Keywords The current experimental study aimed to investigate the inhibitory effects of two food additives (Propionibacterium and acetic acid) at four different concentrations (0.5, 1.0, 2.5 and 5%) on Candida albicans (C. albicans) including recording their impact on the sensory characteristics of the treated chicken fillet samples in chilling conditions (4±1 O C). After physical and microbial examination for nine days of storage, results showed significant improvement in the sensory characteristics of the treated samples, especially with increasing the concentration of the tested additives when compared with the control untreated samples, which were spoiled on the 9 th day of inoculation. Regarding the anti-C. albicans effect of the tested materials, in general, C. albicans showed a higher reduction percent with increasing the concentration of the inoculated additives; furthermore, the treated samples with 2.5% and 5.0% acetic acid, after nine days of inoculation, showed more reduction in C. albicans counts (70.7% and 87.2%) than the treated samples with Propionibacterium of the same concentration (41.4% and 52.7%), respectively. Referring to the obtained results, Propionibacterium and acetic acid (2.5% and 5.0%) can be considered good choices for preserving and enhancing the quality of chilled chicken fillets and may be recommended for their usage in chicken fillet preservation as safe and easily applied food additives.
... Furthermore, the recorded reduction in C. albicans can be referred to its ability to secrete bacteriocins, propanoic acid and vitamin B12 that have direct antifungal effects ( Acetic acid is typically utilized as secure food preservative; they lower the cytoplasmic pH and halt metabolic activities. However, organic acids operate on the plasmic membrane to kill sensitive organisms by neutralizing its electrical potential and increasing its permeability (Dalie et al., 2010 andShaltout et al., 2016). Some methods explain how organic acids' inhibitory mode causes pH to decrease, which may affect the development by acidifying the cell and requiring a lot of energy to maintain intracellular pH equilibrium (Pandey et al., 2016). ...
Article
Full-text available
Keywords The current experimental study aimed to investigate the inhibitory effects of two food additives (Propionibacterium and acetic acid) at four different concentrations (0.5, 1.0, 2.5 and 5%) on Candida albicans (C. albicans) including recording their impact on the sensory characteristics of the treated chicken fillet samples in chilling conditions (4±1 O C). After physical and microbial examination for nine days of storage, results showed significant improvement in the sensory characteristics of the treated samples, especially with increasing the concentration of the tested additives when compared with the control untreated samples, which were spoiled on the 9 th day of inoculation. Regarding the anti-C. albicans effect of the tested materials, in general, C. albicans showed a higher reduction percent with increasing the concentration of the inoculated additives; furthermore, the treated samples with 2.5% and 5.0% acetic acid, after nine days of inoculation, showed more reduction in C. albicans counts (70.7% and 87.2%) than the treated samples with Propionibacterium of the same concentration (41.4% and 52.7%), respectively. Referring to the obtained results, Propionibacterium and acetic acid (2.5% and 5.0%) can be considered good choices for preserving and enhancing the quality of chilled chicken fillets and may be recommended for their usage in chicken fillet preservation as safe and easily applied food additives.
... The results achieved in table (2) revealed that the incidence of yeast contamination in examined ready to eat chicken meat product samples were 0 (0%),15 ...
Article
Full-text available
The present investigation was designed to study the total mould and yeast counts and Aflatoxin residues in a total of 60 random samples of ready to eat chicken products which include Shawerma, smoked chicken breast, Pane and grilled chicken (15 of each) were collected from different localities under different sanitation levels at Cairo governorate.
... One of them is that bacteria may bind or incorporate cholesterol directly into the cell membrane which confirmed by evidences saying that (LAB) lactic acid bacteria are non-pathogenic and safe microbes that generate numerous mature food products. It transforms glucose into lactic acid, ethanol, and CO 2 , all of which improve the quality, surface, and smell of fermented items [18]. Microbial cells normally absorb metal particles due to their utility for creating cell layers [19]. ...
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Background: The toxicity profile of lactobacilli may be strain dependent, so it should be considered for safe utilization of probiotics. Further, in vivo studies are necessary to evaluate their safety. Result: The ability of various probiotic strains to hydrolyze bile salts has been confirmed without noticeable hemolytic activity. Results revealed the presence of α-glucosidase, β-glucosidase, α-galactosidase, and β-galactosidase activity in all investigated isolates, while none of the isolates produced the carcinogenic enzyme β-glucuronidase. The probiotic strains exhibited remarkable cholesterol-lowering impact. Also, we found no evidence of chronic toxicity under the experimental conditions based on gross pathological examination of the viscera and study of the spleen and liver weight ratios. These findings indicated that the investigated strains, either alone or combined with their metabolites, had no obvious adverse effect on the mice's general health status. Conclusion: There is prove that the investigated probiotic strains are safe to be utilized for enhancing of the growth performance and are free of adverse side effects.
... Mold may be present in most foods due to the existence of leftover moisture, which provides a favorable environment for their growth. Mould and yeast growth has been linked to the production of heat stable mycotoxins, which are a major source of concern in the food industry (Dalie et al., 2010). The date ours were within the acceptable limit of 10 2 to 10 4 cfu/g for mould counts (ICMSF, 2002) and therefore, the products are microbiologically safe. ...
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The effect of three drying methods (sun, hot air oven and cabinet drier) on the chemical, functional and microbial properties of date our was comparatively studied. The ash of the two date varieties (amber and sukkari) were washed, dried at 65 o C, milled and sieved to obtain fine flour, and thereafter analyzed. Proximate analysis revealed that hot air oven-dried amber date powder exhibited signicantly (p < 0.05) higher ash (2.64%), fat (5.35%), crude protein (10.50%), crude bre (8.57%) while cabinet dried amber date exhibited the highest sugar (0.125%) and vitamin C (0.024mg/100g) content. Oven-dried amber date powder exhibited higher water absorption (1.10ml/g) and solubility (66.60%). Microbial analysis showed that hot air oven-dried amber and sukaari dates had the lowest total viable count (1.19×10 5 g/CFU/ml and 9.45×10 4 g/CFU/ml, respectively). Thus, the results suggest that hot air oven drying can be appropriately used to obtain date our with good functionality, microbial property and chemical composition.
... The results achieved in table (2) revealed that the incidence of yeast contamination in examined ready to eat chicken meat product samples were 0 (0%),15 ...
Article
Full-text available
The present investigation was designed to study the total mould and yeast counts and Aflatoxin residues in a total of 60 random samples of ready to eat chicken products which include Shawerma, smoked chicken breast, Pane and grilled chicken (15 of each) were collected from different localities under different sanitation levels at Cairo governorate.
... Acetic acids generally used as safe agents to preserve foods, these acids reduce cytoplasmic pH and stop metabolic activities. On the other hand, organic acids cause the death by the susceptible organisms act on the plasmic membrane by neutralizing its electrochemical potential and increasing its permeability [32,33]. Some mechanisms explained the inhibitory mode of organic acids resulting in pH decreasing, this may influence the growth by acidifying the cell, which will consume a great amount of energy to maintain the intracellular pH homeostasis [34]. ...
Article
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Raw meat spoilage by yeasts is a significant problem that is a consequence of many yeast species growth in the product including Candida albicans. Candida albicans utilizes food components and are transformed into many metabolic end products leading to sensory, chemical and physical properties changes with especial reference to the health impacts on the consumer's health. Therefore, the current experimental study aimed to investigate the inhibitory effect of two vital food additives (Propionibacterium and acetic acid) at four different concentrations (0.5, 1.0, 2.5 and 5%) on C. albicans including recording their impact on the sensory characters of the treated chicken fillet samples in chilling conditions (4±1 O C): After physical and microbial examination for nine days of storage, results showed significant improvement in the sensory characters of the treated samples, especially with increasing the concentration of the tested additives when compared with the control untreated samples which was spoiled at the 9th day of inoculation. Regarding with the anti-C. albicans effect of the tested materials, in general, C. albicans showed higher reduction percent with increasing the concentration of the inoculated additives; furthermore, the treated samples with 2.5% and 5.0% acetic acid, after nine days of inoculation, showed more reduction in C. albicans counts (70.7% and 87.2%, respectively) than the treated samples with Propionibacterium of the same concentration (41.4 and 52.7%, respectively): Referring to the obtained results, Propionibacterium and acetic acid of the 2.5% and 5.0% concentration could be considered a good choice for preservation and enhancing quality of chilled chicken fillet, and may be recommended for its usage in chicken fillet preservation as safe and easy applied food additives.
... Sam Woong Kim et al. (2020a) revealed that the CFSs from L. plantarum effectively caused the Salmonella death via pore formation by cellular penetrating peptides (Kim et al. 2020a). Bacteriocins and/or antimicrobial peptides could increase membrane permeability of susceptible bacteria resulting in cellular deformation and cell leakage, accompanied by the release of intracellular components to the environment, thus resulting in cell lysis (Dalié et al. 2010;Klayraung and Okonogi 2009). Furthermore, the loss of membrane integrity results in the collapse of cellular energetics and active transports, quickly leading to cell death (Grégori et al. 2018). ...
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The persistence of Staphylococcus aureus within biofilm can lead to contamination of medical devices and life-threatening infections. Luckily, lactic acid bacteria (LAB) have an inhibitory effect on the growth of these bacteria. This study aims to select LAB strains from fermented vegetables, and analyze their potential inhibition activities against S. aureus. In total, 45 isolates of LAB were successfully isolated from Sichuan pickles, and the CFS of Lactiplantibacillus plantarum LR-14 exerted the strongest inhibitory effect against S. aureus. Moreover, S. aureus cells in planktonic and biofilm states both wrinkled and damaged when treated with the CFS of L. plantarum LR-14. In addition, whole genome sequencing analysis indicates that L. plantarum LR-14 contains various functional genes, including predicted extracellular polysaccharides (EPS) biosynthesis genes, and genes participating in the synthesis and metabolism of fatty acid, implying that L. plantarum LR-14 has the potential to be used as a probiotic with multiple functions.
... Acetic acid is typically utilized as secure food preservative; they lower cytoplasmic pH and halt metabolic activities. However, organic acids operate on the plasmic membrane to kill sensitive organisms by neutralizing its electrical potential and increasing its permeability [32,33] . Some methods explain how organic acids' inhibitory mode causes pH to decrease, which may affect development by acidifying the cell and requiring a lot of energy to maintain intracellular pH equilibrium [34] . ...
Preprint
Full-text available
The current experimental study aimed to investigate the inhibitory effects of two food additives ( Propionibacterium and acetic acid) at four different concentrations (0.5, 1.0, 2.5 and 5%) on Candida albicans ( C. albicans ) including recording their impact on the sensory characteristics of the treated chicken fillet samples in chilling conditions (4 ± 1 O C). After physical and microbial examination for nine days of storage, results showed significant improvement in the sensory characteristics of the treated samples, especially with increasing the concentration of the tested additives when compared with the control untreated samples, which were spoiled on the 9th day of inoculation. Regarding the anti- C. albicans effect of the tested materials, in general, C. albicans showed a higher reduction percent with increasing the concentration of the inoculated additives; furthermore, the treated samples with 2.5% and 5.0% acetic acid, after nine days of inoculation, showed more reduction in C. albicans counts than the treated samples with Propionibacterium of the same concentration. Referring to the obtained results, Propionibacterium and acetic acid (2.5% and 5.0%) could be considered good choices for preserving and enhancing the quality of chilled chicken fillets, and may be recommended for their usage in chicken fillet preservation as safe and easily applied food additives.
... Food spoilage by toxinogenic mold and their mycotoxins constitute a potential health hazard. Moreover, no efficient strategy has been shown to reduce the presence of mycotoxins (Dalié et al., 2010). ...
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The antifungal potentials of two vanadium oxalate compounds (C7H11N2)2[VO(C2O4)2(H2O)]·2H2O (compound 1) and {(CH6N3)2[VO(C2O4)2]}n (compound 2) against Penicillium expansum and Penicillium italicum were investigated. The compounds inhibited both fungi in well diffusion and plate growth inhibition assays and via volatile production methods. Compound 2 was able to reduce spore germination of P. expansum and P. italicum by 40.87% and 42.00%, respectively. Neither compound exhibited cytotoxicity in human cells. In vivo assays with stored apples showed a reduction in a blue mold by 49% and 25% by compounds 1 and 2, respectively. Both compounds were able to completely prevent blue mold in stored oranges. Microscopic examination demonstrated, that compound 2 caused drastic morphological effects on morphogenesis, and limit the spore germination of P. italicum on oranges and the destruction of P. expansum hyphae on apples. Both compounds inhibited biofilm by 78.48% and 73.83% and patulin reduction by 43.31% and 40%, respectively. The present work highlights the successful use of two vanadium oxalate complexes as antifungal agents to reduce blue mold on apples and citrus. Both compounds are able to limit radial growth and spores germination as well as reduce biofilm and Patulin production and affect mycelium morphogenesis.
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The growing interest in functional foods has fueled the hunt for novel lactic acid bacteria (LAB) found in natural sources such as fermented foods. Thus, the aims of this study were to isolate, identify, characterize, and quantify LAB’s antifungal activity and formulate an ingredient for meat product applications. The overlay method performed a logical initial screening by assessing isolated bacteria’s antifungal activity in vitro. Next, the antifungal activity of the fermented bacteria-free supernatants (BFS) was evaluated by agar diffusion assay against six toxigenic fungi. Subsequently, the antifungal activity of the most antifungal BFS was quantified using the microdilution method in 96-well microplates. The meat broth that showed higher antifungal activity was selected to elaborate on an ingredient to be applied to meat products. Finally, antifungal compounds such as organic acids, phenolic acids, and volatile organic compounds were identified in the chosen-fermented meat broth. The most promising biological candidates belonged to the Lactiplantibacillus plantarum and Pediococcus pentosaceus. P. pentosaceus C15 distinguished from other bacteria by the production of antifungal compounds such as nonanoic acid and phenyl ethyl alcohol, as well as the higher production of lactic and acetic acid.
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Probiotics are widely used in functional foods. However, little has been discussed about its potential application in food fortification. Therefore, researchers have studied the possible products that can come out through the presence and activity of probiotics under certain conditions and examined the increase in their nutritional value. In this review, we discuss the most recent data about the role of probiotics in dairy foods in incorporating minerals into amino acids, their ability to synthesize B-complex vitamins and peptides, and the methodological strategies and emerging technologies for quantifying each of these modifications.
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Strain specificity of the starter culture of the dairy probiotic “Narine” ABSTRACT The purpose of this work was to clarify the identity of the starter cultures of a non-ropy fermented milk product called “Narine”, presented on the market. In addition to the absence of the viscosity characteristic of Narine, the samples of this product have higher pH, a short shelf life, significantly lower titer (> 2 log) of living cells by the end of the shelf life. Despite mentioned differences, the starter culture of this product belongs to the species Lactobacillus helveticus. It was found that non-sticky starter culture, when growing in LAPTg medium, begins to lyse after reaching the late logarithmic phase (> 90% of cells). Lysis is characteristic of L. helveticus strains, which are used as starters in the preparation of hard cheeses. Cell lysis of cheese starter cultures is necessary for the release of intracellular endoproteases that break down peptides that give cheeses a bitter taste. However, in the case of probiotic fermented milk products, cell lysis is undesirable because it leads to changes in texture, a decrease in the titer of living bacteria in the product, which makes this strain unsuitable for use as a probiotic. Thus, it can be stated that the strain L. helveticus used in the production of a non-ropy pseudo ″Narine″ product is not the strain L. helveticus MDC9606, and the fermented milk product does not comply with the State Standard of the Republic of Armenia 173-2015 for Narine. Therefore, the non-ropy dairy product has no legal right to be produced under the Narine brand, patented by Professor L. Yerzinkyan. Keywords: Lactobacillus helveticus, sour milk Narine, ropiness, proteases, autolysis, acidity
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Molds are microorganisms capable of both contaminating different food matrices, leading to their organoleptic deterioration, and causing risks to humans due to the development of mycotoxins. To control this type...
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9th conference of Vietnam Hungary
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Lactic acid bacteria (LAB) play a very important role as natural bio-preservatives in foods. Accordingly, the inhibitory effect of Lactobacillus rhamnosus (L. rhamnosus) on 4 fungi species of Yarrowia, Penicillium expansum (P. expansum), Saccharomyces cerevisiae (S. cerevisiae), Aspergillus niger (A. niger), Kluyveromyces lactis (K. lactis) was investigated. Then P. expansum was selected as the most important contaminant mould in yoghurt to study the use of L. rhamnosus to reduce selective spoilage of P. expansum in yoghurt. Also, the effect of this bioprotective culture on the count of starter bacteria and some characteristics of yoghurt was determined. L. rhamnosus (106 cfu /mL) was inoculated into the milk along with yoghurt starter bacteria, so that four samples were produced T0 (L. rhamnosus = 0, P. expansum = 0), T1 (L. rhamnosus = 106 cfu/mL, P. expansum = 0), T2 (L. rhamnosus = 0, P. expansum = 105cfu/mL); T3 (L. rhamnosus = 106 cfu/mL, P. expansum = 105cfu/mL). All samples were analysed for pH, acidity, viscosity, syneresis, microbial (survival of Streptococcus thermophilus and Lactobacillus bulgaricus and P. expansum) and overall acceptability. L. rhamnosus had an inhibitory effect on the survival of P. expansum (p<0.05) but was not able to completely control it. L. rhamnosus in T3 sample had an inhibitory effect from the first day to the end of storage. Furthermore, during the storage, the survival of yoghurt starter bacteria in probiotic yoghurt samples was higher than the control (p<0.05). T3 had lower pH, viscosity and overall acceptability score compared to the control and its syneresis was higher (p<0.05). In general, the addition of 106 cfu/mL of L. rhamnosus did not have a complete inhibitory effect on P. expansum (105 CFU/mL) until the end of storage time.
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Predominant antifungal lactic acid bacteria (LAB) isolated from fermented sprouted mung bean (FSM) was used as protective starter culture in controlled FSM to produce a clean‐label fortified wheat bread. Sequencing results of the PCR products led to the identification of Pediococcus pentosaceus as the selected LAB isolate. The rate of surface growth of Aspergillus niger on FSM added bread was significantly (p<0.05) lower than the wheat bread containing mung bean, fermented mung bean and sprouted mung bean alone. The quantity of almost all of the amino acids (aspartic acid, histidine, serine, arginine, threonine, tyrosine, valine, phenylalanine and tryptophane) in the FSM added wheat bread was also higher than the control, according to the HPLC analysis. Furthermore, bread containing FSM had the highest mould‐free shelf‐life (4 days) and porosity (21.61%). Meanwhile, there was no significant (p>0.05) difference in terms of crumb hardness, specific volume and overall acceptability among the produced samples.
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Aflatoxins (AFs) are the most important toxic, mutagenic, and carcinogenic fungal toxins that routinely contaminate food and feed. While more than 20 AFs have been identified to date, aflatoxin B1 (AFB1), B2 (AFB2), G1 (AFG1), G2 (AFG2), and M1 (AFM1) are the most common. Over 25 species of Aspergillus have been shown to produce AFs, with Aspergillus flavus, Aspergillus parasiticus, and Aspergillus nomius being the most important and well-known AF-producing fungi. These ubiquitous molds can propagate on agricultural commodities to produce AFs in fields and during harvesting, processing, transportation, and storage. Countries with warmer climates and that produce foods susceptible to AF contamination shoulder a substantial portion of the global AF burden. Pakistan’s warm climate promotes the growth of toxigenic fungi, resulting in frequent AF contamination of human foods and animal feeds. The potential for contamination in Pakistan is exacerbated by improper storage conditions and a lack of regulatory limits and enforcement mechanisms. High levels of AFs in common commodities produced in Pakistan are a major food safety problem, posing serious health risks to the population. Furthermore, aflatoxin contamination contributes to economic losses by limiting exports of these commodities. In this review, recent information regarding the fungal producers of AFs, prevalence of AF contamination of foods and feed, current regulations, and AF prevention and removal strategies are summarized, with a major focus on Pakistan.
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Chapter
Lactic acid bacteria (LAB) are ubiquitous bacteria associated with spontaneous lactic fermentation of vegetables, dairy and meat products. They are generally recognized as safe (GRAS), and they are involved in transformation of probiotic lacto-fermented foods, highly desired for their nutraceutical properties. The antifungal activity is one of the exciting properties of LAB, because of its possible application in food bio-preservation, as alternative to chemical preservatives. Many recent research works have been developed on antifungal activity of LAB, and they demonstrate their capacity to produce various antifungal compounds, (i.e. organic acids, PLA, proteinaceous compounds, peptides, cyclic dipeptides, fatty acids, and other compounds), of different properties (hydrophilic, hydrophobic and amphiphilic). The effectiveness of LAB in controlling spoilage and pathogenic fungi, demonstrated in different agricultural and food products, can be due to the synergistic effect between their antifungal compounds of different properties; where the amphiphilic-compounds allow the contact between the target microbial cell (hydrophilic compartment) and antifungal hydrophobic-compounds. Further studies on the interaction between compounds of these three properties are to de be developed, in order to highlight more their mechanism of action, and make LAB more profitable in improving shelf life and nutraceutical properties of foods.
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Mycotoxin contamination of food and feed is a serious food safety issue and causes acute and chronic diseases in humans and livestock. Climatic and agronomic changes helps in the proliferation of fungal growth and mycotoxin production in food commodities. Mycotoxin contamination has attracted global attention due to its wide range of toxicity to humans and animals. However, physical and chemical management approaches in practice are unsafe for well-being due to their health-hazardous nature. Various antibiotics and preservatives are in use to reduce the microbial load and improve the shelf life of food products. In addition, the use of antibiotic growth promotors in livestock production may increase the risk of antimicrobial resistance, which is a global health concern. Due to their many uses, probiotics are helpful microbes that have a significant impact on food and nutrition. Furthermore, the probiotic potential of lactic acid bacteria (LAB) is employed in various food and feed preparations to neutralize mycotoxins, antimicrobial activities, balance the gut microbiome, and various immunomodulatory activities in both humans and livestock. In addition, LAB produces various antimicrobials, flavouring agents, peptides, and proteins linked to various food and health care applications. The LAB-based processes for mycotoxin management are more effective, eco-friendly, and low-cost than physical and chemical approaches. The toxicity, novel preventive measures, binding nature, and molecular mechanisms of mycotoxins' detoxification using LAB have been highlighted in this review.
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Paocai is a traditional Chinese fermented vegetable product popular in Asian countries. As an important additive, salt concentration is closely related to the quality of paocai. The aim of this study was to investigate the effect of salt concentration on the physicochemical characteristics, microbial diversity, and flavor profiles of spontaneously fermented radish, and the cross-correlation between microorganisms and flavor compounds was also revealed. Analysis of the microbial diversity of paocai showed that Firmicutes, Proteobacteria, and Ascomycota were detected as the main phyla with different salt concentrations, Weissella and Lactobacillus were the predominant bacterial genera, and Yarrowia dominated the fungal genera. Based on LEfSe analysis, Lactobacillus, Allorhizobium-Neorhizobium-Pararhizobium-Rhizobium, Microbacterium, Lactococcus, Staphylococcus, and Weissella were regarded as differential genera caused by differences in salinity. Analysis of the flavor compounds showed that 17 free amino acids, 5 isothiocyanates, 3 terpenes, 15 sulphur-containing compounds, 16 esters, 8 organic acids, 9 aldehydes, 8 ketones, 25 alcohols, 7 nitriles, 2 lactones, and 10 hydrocarbons were detected. Then, the correlation between the microbial community and flavor compounds was revealed, and the results indicated that several bacterial genera significantly correlated with flavors, including Lactobacillus, Kosakonia, Weissella, Leuconostoc, and Staphylococcus, while fungi had weak correlations with flavors. In addition, Metacyc pathway analysis was carried out to elucidate the effect of salt content on the metabolic pathways, showing that most flavor-related pathways were up-regulated with the increase in salt content. Results presented in this study may contribute to further understanding the role of salt in the fermentation of paocai and provide effective references for quality control of traditional fermented vegetables.
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The present study pertains to the effect of nutritional factors on the growth and production of antimicrobial substances (AS) by Streptococcus lactis subsp. diacetylactis S1-67/C. Among nine media tested, yeast extract dextrose broth supported good growth and maximum production of AS. Addition of beef extract and yeast extract at 1.0 and 0.6% levels, respectively, increased growth as well as production of AS. Of ten carbohydrates examined, maximum production of AS was achieved with 1% glucose followed by fructose, 4% molasses, lactose, sucrose, galactose, mannitol, maltose and 2% molasses. Xylose inhibited production of AS, although it stimulated growth of the organism. Peptone, tryptone and tryptose (each at the 1.5% level) significantly stimulated production of AS. Other nitrogen sources, including soytone, casein hydrolysate and proteose peptone, retarded production of inhibitory substances. Among the amino acids, L-leucine, DL-methionine and L-glutamic acid were most essential for growth and production of AS, whereas L-lysine, L-proline, DL-serine, DL-asparatic acid, L-arginine-HCl and DL-tryptophan were stimulatory. Other amino acids such as DL-ornithine, L-cysteine-HCl and DL-citrulline slightly stimulated AS production. In the presence of cynocobalmin, niacin, folic acid, calcium pantothenate and riboflavin, S. lactis subsp. diacetylactis S1-67/C produced maximum amounts of inhibitory substances. Omission of individual mineral salts from the basal medium did not affect production of AS by the organism.
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Lactobacillus reuteri resides in the gastrointestinal (GI) tract of humans and animals (Kandler et al., 1980). Often misclassified as L. fermentum in the past, this heterofermentative species is now recognized as a distinct member of the genus Lactobacillus (Kander and Weiss, 1986). Our laboratories have obtained evidence that L. reuteri (i) produces a potent, broad-spectrum antimicrobial substance, termed reuterin (Axelsson et al, 1988), (ii) is prominently represented among lactobacilli found in the stomach and proximal regions of the swine GI tract (Pagano et al, 1988) and (iii) may play an important role in the health and well-being of its host (Chung et al, 1988). The first report on the L. reuteri-reuterin system was presented at the Second Symposium on Lactic Acid Bacteria (Axelsson et al., 1987), and studies on this system are in various stages of publication. In this report our current understanding of this system is outlined and updated with new information.
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The effect of three individual species of lactobacilli (Lactobacillus acidophilus, L. bulgaricus, and L. plantarum) and a commercial silage inoculant, containing three different strains of the same species, on growth and aflatoxin production of A.flavus subsp. parasiticus NRRL 2999 was determined. The study was done in three substrates; a liquid semi-synthetic broth, rice, and corn. The effect of the growing cell masses of the lactobacilli as well as the effect of metabolic products contained in cell free filtrates were determined in the liquid medium. The cells were effective in preventing growth of the mold, and bacterial metabolites were effective in reducing the amount of aflatoxin produced, although growth was not affected. The prevention of growth that was observed was determined to be relative to a pH effect and microbial competition; however, the lower levels of aflatoxin obtained in the presence of cell free supernatant culture fluids could not be explained on the basis of pH or competition. Mold growth was not affected by the presence of the silage inoculant on the rice and corn. However, increased levels of aflatoxin B1 were observed in the presence of the silage inoculant on rice, and decreased levels of aflatoxin G1 were observed on the presence of the silage inoculant on corn. Copyright © International Association of Milk, Food and Environmental Sanitarians.
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The ability of lactic acid bacteria (LAB) and Saccharomyces cerevisiae to remove aflatoxin B1 (AFB1) from liquid medium was tested. The experimental results indicated that (i) AFB1 binding to microorganisms was a rapid process (no more than 1 min); (ii) this binding involved the formation of a reversible complex between the toxin and microorganism surface, without chemical modification of the toxin; (iii) the amount of AFB1 removed was both toxin- and bacteria concentration–dependent; and (iv) quantitatively similar results were obtained with viable and nonviable (heat-treated) bacteria. According to these details, a physical adsorption model is proposed for the binding of AFB1 to LAB and S. cerevisiae, considering that the binding (adsorption) and release (desorption) of AFB1 to and from the site on the surface of the microorganism took place (AFB1 + S ↔ S − AFB1). The model permits the estimation of two parameters: the number of binding sites per microorganism (M) and the reaction equilibrium constant (Keq) involved, both of which are useful for estimating the adsorption efficiency (M × Keq) of a particular microorganism. Application of the model to experimental data suggests that different microorganisms have similar Keq values and that the differences in toxin removal efficiency are mainly due to differences in M values. The most important application of the proposed model is the capacity to select the most efficient microorganism to remove AFB1. Furthermore, it allows us to know if a modification of the adsorption efficiency obtained by physical, chemical, or genetic treatments on the microorganism is a consequence of changes in M, Keq, or both.
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Pediococcus acidilactici LAB 5 produces antifungal compound(s), as well as bacteriocin, which was isolated from vacuum packed fermented meat. This bacterium exhibits varying degrees of antifungal activity against a number of food and feed home molds and plant pathogenic fungi, such as Alternaria solani, Aspergillus fumigaus, A. parasiticus, Cladosporium herbarum, Colletotrichum acutatum, Curvularia lunata, Fusarium oxysporum, Microsporium sp, Mucor sp, and Penicillium sp. The production of antifungal compound(s) showed a great degree of media specificity and it was strictly restricted to MRS agar media. No production of antifungal compounds was detected in TGE, and TGE(+) Tween 80 plates, though the latter supported the highest amount of bacteriocin production at 37 degrees C after 24 hrs. Antifungal compound produced by LAB 5 was extracted using diethyl ether. The minimum inhibitory concentration (MlC) and minimum fungicidal concentration (MFC) of the compound were determined against Curvularia lunata. Chemically the antifungal substance was a phenolic compound with aromatic unsaturation, as evidenced by UV and IR spectroscopy. This is the first report of the production of antifungal compounds by Pediococcus acidilactici LAB 5.
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The detoxification ability and toxin binding properties (ability and strength) of aflatoxin B1 by six strains of probiotic bacteria were studied. The detoxification ability of the organisms ranged between 20-50%. About 60-80% of the bound aflatoxin was removed when washed with water, and only 10-40% of the toxin was strongly bound to the bacterial cells. Among the organisms studied, Bifidobacterium infantis 1912 demonstrated a significantly higher aflatoxin binding ability than the other strains, while Bifidobacterium pseudolongum 20099 showed the least aflatoxin binding ability of about 10% of the added 50 ng of aflatoxin B1. Bifidobacterium bifidum 1 showed the least aflatoxin B1 binding strength during the 180 min treatment.
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A mixture of Lactobacillus species from a commercial silage inoculum reduced mold growth and inhibited aflatoxin production by Aspergillus flavus subsp. parasiticus. Actively growing Lactobacillus spp. cells totally inhibited germination of mold spores. Culture supernatant broth from the mixture of strains inhibited mold growth but did not destroy mold spore viability. Some mold spores were observed microscopically to have germinated and produced short nonbranching germ tubes; then growth ceased. While the pH of the culture broth and supernatant were about 4.0, acidification of nonfermented broth to pH 4.0 with HCl and lactic acid did not cause a similar inhibition of spore germination. The mixture of Lactobacillus species growing in a dialysis sack inhibited aflatoxin production by the A. flavus culture growing outside of the sack in broth, whereas mold growth was not affected. The pH values outside of the dialysis sack in the control and the treatments were similar (6 to 7) throughout the incubation period. When a dialysis sack with a molecular weight cutoff (MWCO) of 1,000 was used, there was little inhibition of aflatoxin B1, production, but with MWCOs of 6,000 to 8,000 and 12,000 to 14,000 aflatoxin production was greatly inhibited. In mixed culture experiments, levels of aflatoxin B1 and G1 were depressed compared to the control (monoculture). Mold growth in this case was also reduced compared to the monoculture system. Purified isolates of Lactobacillus from the commercial mixture had a slight effect on mold growth and aflatoxin production, but supernatant liquid of one isolate was quite inhibitory to production of aflatoxins B1 and G1, without affecting mold growth.
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A collection of glycerol-degrading lactic acid bacteria from spoiled cider was isolated The most widespread species was Lactobacillus collinoides, a heterofermentative species which mainly produced the D-lactic acid isomer from glucose. Conditions of glycerol assimilation by such bacteria were investigated for strain tb, collinoides IOEB 9527 It could not be cultivated with glycerol alone as carbon source. Sugars were necessary for growth, and fructose was preferred to glucose. Glycerol was degraded, mainly to 1,3-propanediol Small amounts of acrolein, produced from 3-hydroxypropion-aldehyde (3-HPA) during distillation of samples, were detected When Lb, collinoides was cultivated with glucose or fructose alone, it produced the usual compounds of the heterofermentative pathway, notably D-lactic acid and small amounts of L-lactic acid, acetic acid and ethanol. When glycerol was present, the amounts of lactic acid were surprisingly much lower and acetic acid + ethanol much higher than expected Oxidation of D-lactic acid, and to a lesser extent of L-lactic acid, was coupled to degradation of glycerol to 1,3-propanediol This co-metabolism leading to acetic acid provided energy. Consequently, in fermented beverages spoiled by such strains, glycerol is degraded and 3-HPA plus acetic acid are produced. Both components are undesirable for health and sensorial qualify.
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A study was carried out to evaluate the efficacy of Saccharomyces cerevisiae ( SC ) as an inhibitor of aflatoxicosis in broilers. Clinic, pathologic, immune and productive aspects of broilers fed with aflatoxin in the diets were studied. The results showed that the feed intake and weight gain were negatively affected (P < 0.01) for aflatoxin in diet (1000 ppb). The SC (0, 20%) added to diet did not ameliorated the negatively aflatoxin effect at broiler weight gain, however the SC improve the feed conversion in this birds. The humoral immune response of broilers vaccinated against Newcastle virus disease (NDV) was reduced for aflatoxin in diet, as also the liver, kidneys and bursa of Fabricius were negatively affected for this toxin at diet. The SC did not improve the hemagglutination inhibiting antibody titers in birds fed with aflatoxin in diet, however improve the immune response of broilers at challenge with strain velogenic of NDV.
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Some foods are prone to contamination with aflatoxins, with detrimental effect on human health. Lactic acid bacteria have been reported to bind aflatoxins and remove them from foods and feeds. Reduction of aflatoxin B1 (AFB1) from the liquid media by the autochthonous lactic acid bacteria (Lactobacillus casei, Lactobacillus plantarum, and Lactobacillus fermentum) isolated from traditional Iranian sourdough and dairy products is reported in the current study. The effect of incubation time on the binding capacity of the strains to AFB1 was also investigated. Duplicates of individual bacteria with population equivalent to 2 X 10(10) CFU/ml were incubated in the presence of AFB1 at 37 degrees C for a period of 72 h, and the amounts of unbound AFB1 were quantitated by reverse-phase high-performance liquid chromatography. All the strains were capable of removal of AFB1, and the reduction of AFB1 ranged from 25 to 61% throughout the incubation period. Removal of AFB1 was a rapid process, with approximately 61 and 56% of the toxin taken instantly by L. fermentum and L. plantarum, respectively. Binding was of a reversible nature, and some of the bound AFB1 was released into the media by the repeated centrifugation and resuspension of the cell pellets. The stability of the bacteria-toxin complex was strain dependent, and L. casei was a stronger binder of AFB1 compared with the other bacteria. No toxin release was observed after 24 h. These findings tend to suggest that certain novel probiotic bacteria with high aflatoxin binding capacity could be selected for detoxification of foods.
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The inoculation of Aspergillus flavus spores into a culture of Streptococcus lactis in Lablemco tryptone broth medium resulted in little or no aflatoxin accumulation even though the growth of the fungus was not hindered. The drop in pH and reduced nutrient levels in the medium as a result of the S. lactis growth were not the cause of the observed inhibition. The inhibition was not eliminated by the addition of carbohydrate equal to the amount used by the bacterium before the inoculation with the fungus. Aflatoxin levels were also markedly reduced when S. lactis was inoculated into a growing A. flavus culture. In addition to inhibiting the synthesis of aflatoxin, S. lactis also degraded preformed toxin. A. flavus, on the other hand, not only reduced the growth of S. lactis but also affected the morphology of the bacterial cell; the cells became elongated and formed long chains. S. lactis produced and excreted the inhibitor into the medium late in its growth phase. The inhibitor was a heat-stable low-molecular-weight compound. Chloroform extracts of A. flavus grown in the presence of S. lactis were toxic to Bacillus megaterium but did not exhibit mutagenic or carcinogenic activity in the Salmonella/mammalian microsome mutagenicity test.
Article
A commercial silage inoculant mixture of Lactobacillus species inhibited aflatoxin production by Aspergillus flavus subsp parasiticus. Germination of mold spores was inhibited by actively growing Lactobacillus cells, however Lactobacillus cell free supernatant did not affect mold spore viability. Aflatoxin production was inhibited in Lablemco Tryptone Broth (LTB) by Lactobacillus species growing inside dialysis sacks (molecular weight cutoffs of 1000, 6-8000 and 12-14,000) immersed in the LTB. Aflatoxin levels were also significantly reduced when Lactobacillus species were inoculated into a growing mold culture, and also when mold spores were injected into Lactobacillus cultures. Different Lactobacillus isolates were purified from the silage inoculant mixture. Some of the isolates had no effect on mold growth and aflatoxin production. Other Lactobacillus isolates showed various degrees of aflatoxin inhibition. Lactobacillus isolate 371, which was identified as Lactobacillus casei pseudoplantarum, was found to greatly inhibit the production of aflatoxins B1 and G1. The inhibition of aflatoxins by Lactobacillus casei pseudoplantarum 371 was not eliminated by replacing an amount of glucose equal to the amount used by Lactobacillus sp before inoculation of the mold. The inhibitory principle in a Lactobacillus cell free supernatant was found to be sensitive to trypsin and $\alpha$-chymotrypsin, but not to pepsin. Dialyzed protein concentrate of the Lactobacillus cell free supernatant greatly inhibited aflatoxin formation. The antiaflatoxigenic activity of the supernatant was destroyed at 100 C within 10 mn. While Lactobacillus casei pseudoplantarum 371 inhibited aflatoxin production in broth, it did not have any effect on mold growth and aflatoxin production in sterile steamed rice, when mold growth was monitored by ergosterol and plate count techniques. Ergosterol determination was found to be a sensitive indicator of low levels of fungal activity and aflatoxin production in rice. Ergosterol formation in rice followed the same trend as aflatoxin B1 production. The inhibitory activity of the Lactobacillus isolate was shown to inactivate the enzymatic system required for the production of aflatoxin B1.
Chapter
Foods have been preserved by the action of lactic acid bacteria long before the science of microbiology began and it is probable that milk fermented by lactic acid bacteria was consumed at least 11 000 years ago. Man has unwittingly developed a number of fermentation processes to produce a large range of fermented dairy products, vegetables, meats, fish and cereals (Gilliland, 1985; Wood, 1985; Lücke & Earnshaw, 1991). In the Third World many of these fermented foods are produced under relatively unhygienic conditions and yet retain a good record with respect to microbiological safety. Fermentation also alters the sensory characteristics of foods often resulting in a product of increased commercial value, however, this chapter is concerned solely with the antimicrobial action of lactic acid bacteria, particularly those associated with food.
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Spores of Botrytis cinerea can germinate in the presence of up to 180 mM hydrogen peroxide and its mycelium can develop in the presence of even higher concentrations. The mycelium can breakdown hydrogen peroxide present in its culture medium rapidly in a time-dependent manner. This breakdown depends on the composition of the culture medium, is not inhibited by inhibitors of catalase activity, but is considerably reduced by inhibitors of peroxidase, such as benzhydroxamic acid, and by caffeic acid. In addition, growth in the presence of inducers of laccase formation appears to promote subsequent breakdown of hydrogen peroxide.
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Bacteriocins produced by lactic acid bacteria have a bactericidal effect against Gram-positive bacteria including foodborne pathogens such as Listeria monocytogenes, Bacillus cereus, and also inhibit the outgrowth of bacterial spores. Most of these bacteriocins are degradable in human tract, and heat stable, so that bacteriocins produced by lactic acid bacteria have potential use as natural food preservatives. Actually, nisin produced by the food-grade bacterium Lactococcus lactis is recognized as GRAS (Generally Recognized As Safe) substance and widely used as a preservative in the food industry. In recent years there has been a considerable increase in studies of bacteriocins produced by lactic acid bacteria not only on their structure, biosynthesis and mechanisms of pore-formation, but also on their potential applications as food preservatives. This review describes the current knowledge about the properties, biosynthesis, functional aspects, producer self-protection and resistance of a broad range of bacteriocins from lactic acid bacteria as well as the applications.
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Although, oxidative stress response, which protects organisms from deleterious effects of reactive oxygen species (ROS), has been extensively studied in pro- and eukaryotes, the information about filamentous fungi is fragmentary. We investigated the effect of two ROS-generating agents (paraquat, PQ, and H2O2) on cellular growth and antioxidant enzyme induction in 12 fungal species. Our results indicate that exposure of fungal spores or mycelia to PQ and H2O2 promoted oxidative stress, as evidenced by remarkable inhibition of spore germination and biomass production; stimulation of cyanide-resistant respiration; accumulation of oxidative modified proteins. Cell responses against both superoxide and peroxide stresses include enhanced expression of superoxide dismutase (SOD) and catalase, however, the extent was different: treatment with PQ increased mainly SOD, whereas exogenous H2O2 led to enhanced catalase. We also found that G6PD has a role in the mechanism of protection against superoxide and peroxide stresses. The activation of antioxidant enzyme defence was blocked by the translation inhibitor, cycloheximide, suggesting that there was de novo enzyme synthesis.
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Three strains of Lactobacillus brevis and one strain of Lactobacillus buchneri grew very poorly on glucose. Good growth was observed on glucose plus glycerol; while glucose was fermented to acetate or ethanol, lactate and CO2, glycerol was dehydrated to 3-hydroxypropanal and subsequently reduced to propanediol-1.3. Cell extracts of L. brevis and L. buchneri grown on glucose plus glycerol contained a B12-dependent glycerol dehydratase and a propanediol-1.3 dehydrogenase. Glycerol was not metabolized when used as the only substrate. Fructose as sole carbon source was partially reduced to mannitol. The joint fermentation of fructose and glycerol yielded propanediol-1.3 from glycerol. Ribose was fermented but did not support glycerol fermentation. Extracts from ribose grown cells did not contain glycerol dehydratase or propanediol-1.3 dehydrogenase. Besides glycerol the following diols were metabolized as cosubstrates with glucose: propanediol-1.2, ethylene glycol and butanediol-2.3 yielding propanol-1, ethanol and butanol-2 respectively. Washed cells of two L. brevis strains, B 18 and B 20, formed propanediol-1.3 and propanediol-1.2 from glycerol, the third strain B 22 formed only propanediol-1.2 from glycerol in the absence of glucose.
Article
Lactic acid bacteria isolated from dairy products, vegetables and fruits were screened for their antifungal and antimycotoxigenic activities. From 420 isolates tested, four isolates were found to be inhibitory to fourPenicilliumspecies. Two of the lactic acid bacteria isolates showed the largest inhibitory activity againstPenicillum citrinumandPenicillium expansum. The two isolates were identified asLactobacillus caseispecies. Production of patulin and citrinin was also inhibited in the presence of theLactobacillisupernatants. The inhibitory activity in the twoLactobacillicell-free supernatants was shown to be unrelated to the production of lactic acid or hydrogen peroxide, and was found to be sensitive to proteolytic enzymes and to high temperature (100 °C). The antimycotoxigenic activity was not affected by the addition of glucose used byLactobacillispecies during incubation.
Article
Lactobacillus reuteri resides in the gastrointestinal ecosystem of humans and other animals. In an earlier report we showed that this enteric species converts glycerol into reuterin—a substance with broad-spectrum antibacterial activity. In this report we show that reuterin also has antimycotic and antiprotozoal activity. A minimum inhibitory concentration (MIC) assay was developed and used to study the conditions under which reuterin is synthesised. The results show reuterin to be synthesised in vitro under pH, temperature and relative anaerobic conditions similar to those believed to exist in the regions of the gastrointestinal ecosystem inhabited by L.reuteri. It was also demonstrated that L.reuteri cells are stimulated to produce reuterin when permitted to interact directly with a variety of other microorganisms. A symbiotic relationship between L.reuteri and its host is postulated and discussed.
Article
Spores of Botrytis cinerea can germinate in the presence of up to 180 mM hydrogen peroxide and its mycelium can develop in the presence of even higher concentrations. The mycelium can breakdown hydrogen peroxide present in its culture medium rapidly in a time-dependent manner. This breakdown depends on the composition of the culture medium, is not inhibited by inhibitors of catalase activity, but is considerably reduced by inhibitors of peroxidase, such as benzhydroxamic acid, and by caffeic acid. In addition, growth in the presence of inducers of laccase formation appears to promote subsequent breakdown of hydrogen peroxide.
Article
This study assessed the ability of thermolysed, active yeast, Saccharomyces cerevisiae, and manno-oligosaccharides, to reduce the effects of aflatoxins in animals. A basic ration was developed with six different formulations. Each formulation was considered a treatment. The treatments were: an aflatoxin-free formulation, an aflatoxin control (400 g kg–1) and four aflatoxin-supplemented formulations. The supplements were 0.1 and 0.2% manno-oligosaccharides, 1% thermolysed yeast and 1% dehydrated active yeast. The experiment was randomly designed and had five repetitions per treatment. The feed was contaminated with aflatoxins from naturally contaminated peanuts. A bioassay with Wistar rats was conducted after 28 days. The aflatoxin toxicity was evaluated by weighing body organs (heart, kidneys and liver) and by analysing the liver tissue of the animals. No significant differences were observed for the weights of the body organs from the animals fed with the different rations. However, the analysis of the liver tissue showed animals fed with 400 g of aflatoxin kg–1, and those fed diets with aflatoxin amended with either manno-oligosaccharides or with thermolysed yeast had clear signs of toxicity and damage, while those fed with dehydrated active yeast showed less intense toxicity and less liver damage. Therefore, the thermolysed yeast and manno-oligosaccharides did not suppress damage to liver tissue caused by aflatoxins, while active yeast reduced the aflatoxin symptoms in the hepatocytes.
Article
Antifungal activity of eleven selected bacterial cultures and five microfungi in different phases of their growth were investigated in respect of their activity against Penicillium expansum (Link.) Thom. The dynamics of linear growth and mycelium mass growth as well as the ability to produce patulin were examined. The results indicate that two bacteria Bacillius megaterium and Bacillus subtilis species and three strains of the genus Lactobacillus: L. casei, L. delbrueckii ssp. bulgaricus, and L. lactis ssp. cremoris are active against Penicillium expansum.
Article
The ability of lactic acid bacteria (LAB) to inhibit Aspergillus, Fusarium, and Penicillium, the main contaminants in bread, was evaluated. Only four strains (Lactobacillus plantarum CRL 778, Lactobacillus reuteri CRL 1100, and Lactobacillus brevis CRL 772 and CRL 796) from 95 strains tested displayed antifungal activity. The major antifungal compounds were acetic and phenyllactic acids. The fermentation quotient (FQ = 2.0) and the leaven volume (80 cm3) of doughs with LB and yeasts were higher than doughs without LB. The inclusion of antifungal LAB strains in the starter culture allowed a reduction in the concentration of calcium propionate by 50% while still attaining a shelf life similar to that of traditional bread containing 0.4% CP.
Article
Food-borne fungi, both yeasts and moulds, cause serious spoilage of stored food. Moulds may also produce health-damaging mycotoxins, e.g. aflatoxins, trichothecenes, fumonisin, ochratoxin A and patulin. Consumer demands for minimally processed foods and reduced use of chemical preservatives have stimulated research on antifungal lactic acid bacteria as biopreservatives. Recently, a number of antifungal metabolites, e.g. cyclic dipeptides, phenyllactic acid, proteinaceous compounds, and 3-hydroxylated fatty acids have been isolated from lactic acid bacteria. This review summarizes these findings and suggests potential applications of antifungal lactic acid bacteria in the preservation of food and feeds.
Article
A real-time polymerase chain reaction (PCR) system specific for the ochratoxin A polyketide synthase gene (otapksPN) of Penicillium nordicum has been used to analyze environmental conditions, influencing the induction of that key gene of the ochratoxin A biosynthetic pathway. Generally, the induction of that gene coincides very well with the biosynthesis of ochratoxin A, demonstrating that its induction can be used as a molecular signal to monitor ochratoxin A production. It could be shown, that the expression of the otapksPN gene is greatly dependent on the media used. In YES medium expression is highest, followed by minimal medium which support ochratoxin A production and minimal medium which suppresses ochratoxin A production. The amount of ochratoxin A produced shows the same tendency. The amount produced is highest on YES medium and decreases successively to the two minimal media. The system was also used to determine the influence of environmental parameters like temperature, pH and NaCl concentration on the expression of the otapksPN gene and on ochratoxin A production in parallel. It could be shown that under acidic conditions, below pH 5.0, the expression of the otapksPN gene as well as the ochratoxin A concentration were reduced. In case of salt concentration again both measures coincide, having both highest values at increasing NaCl concentrations. In case of the temperature, however, expression of the otapksPN gene was uncoupled to ochratoxin A production. The expression was high at all temperatures tested, however, clear differences in the biosynthesis of ochratoxin A by P. nordicum could be observed at the different temperatures, showing highest production at 25 degrees C. The importance of these data are discussed with reference to the natural habitat of P. nordicum.
Article
Miso, a widely used Japanese fermented food was analysed for its lactic acid bacterial count on bromocresol purple agar. The binding of eight different foodborne carcinogenic heterocyclic amines to 25 bacterial isolates from miso were investigated. The heterocyclic amines used were 3-amino-1,4-dimethyl[5H]pyrido(4,3-b)indole (Trp-P-1), 3-amino-1-methyl[5H]pyrido(4,3-b)indole (Trp-P-2), 2-amino-6-methyldipyrido(1,2-a:3'2'-d)imidazole (Glu-P-1), 2-amino-1-methyl-6-phenylimidazo(4,5-b)pyridine (PhIP), 2-amino-dimethylimidazo(4,5f)quinoline (IQ), 2-amino-3,4-dimethylimidazo(4,5-f) quinoline (MeIQ), 2-amino-3,8-dimethylimidazo(4,5-f)quinoxaline (MeIQx), and 2-amino-3-methyl-9H-pyrido(2,3)indole (MeA alpha C). The lyophilized cells of all of the isolates exhibited high binding activity towards Trp-P-1, Trp-P-2, MeA alpha C, and PhIP, while Glu-P-1 and IQ were not effectively bound. Of the isolates tested, the strongest and weakest binders were identified as Pediococcus acidilactici 1 and 2, respectively. Lyophilized cell wall fractions, heat-treated cells, and the cytoplasmic contents of P. acidilactici 1 and 2 were analysed for their ability to bind to different mutagens. Pure cell wall and peptidoglycan showed greater binding activity than the bacterial cells. Cytoplasmic content also showed some binding, but it was much less effective. The impact of enzymes (amylase, protease, cellulase, chitinase, muraminase, and peptidase) and acetylation of Trp-P-1 and IQ on the binding action of bacteria and cell wall material were also analysed to understand the possible processes involved in the binding of lactic acid bacteria to carcinogenic heterocyclic amines.
Article
This study set out to discover whether the findings of St James-Roberts and Halil (1991), Infant crying patterns in the first year, Journal of Child Psychology and Psychiatry, and McGlaughlin and Grayson (1999) A prospective study of crying during the first year of infancy, Journal of Reproductive and Infant Psychology, could be replicated. Mothers who attended child health clinics with their infants were interviewed using a revised version of the Crying Patterns Questionnaire. This asks about mothers' perceptions of the amount their infant cries at six different periods of the day. The sample of 297 mothers was divided into four groups, according to the age of their infants (1-3 months, 4-6 months, 7-9 months, 10-12 months). In this way patterns of perceived daily crying across the first year of life were identified. The findings reported in this paper lend strong support to those of St James-Roberts and Halil and confirm the conclusion of McGlaughlin and Grayson that perceived time of day crying peaks are concentrated in the later part of the afternoon and early part of the evening.
Article
Lactic acid bacteria can produce a variety of antimicrobial compounds which may affect both the lactic acid bacteria themselves as well as undesirable or pathogenic strains. In this first section, we describe the biosynthesis, mode of action and activity spectra of these inhibitors. Metabolites of oxygen (hydrogen peroxide and free radicals) exhibit a bacteriostatic or bactericidal activity against lactic or non-lactic flora. When associated with the lactoperoxidase / thiocyanate system, hydrogen peroxide leads to the formation of inhibitory compounds which are bacteriostatic for lactic acid bacteria and bactericidal for Gram-negative bacteria. The antimicrobial activity of organic acids (lactic, acetic and formic) and of pH are closely linked. It appears that the non-dissociated fraction of these acids is the major inhibitory form. Thus, acetic acid whose pKa is higher than that of lactic acid exhibits the highest inhibitory activity. The antimicrobial activities of diacetyl, acetaldehyde and of the D isomers of amino acids are also described, although their effects are slight in usual lactic fermentations. Bacteriocins are the last type of inhibitory substance produced by some lactic acid bacteria. They will be described in a second section. Les bactéries lactiques sont capables de produire une variété de produits inhibiteurs dont les effets peuvent se répercuter sur la flore lactique elle-même mais aussi sur les flores indésirables ou pathogènes. Dans cette première partie, nous décrivons les mécanismes d'apparition, les modes d'action et les spectres d'activité de ces inhibiteurs. Les métabolites de l'oxygène (le peroxyde d'hydrogène et les radicaux libres) peuvent avoir des effets biologiques de nature bactériostatique ou bactéricide sur la flore lactique ou non lactique. Le peroxyde d'hydrogène associé au système lactoperoxydase / thiocyanate, catalyse la formation de produits inhibiteurs, bactériostatiques pour la flore lactique et bactéricides pour les bactéries Gram-négative. Les pouvoirs antibactériens des acides organiques et du pH sont intimement liés. Il semble que la fraction non dissociée de ces acides soit la forme inhibitrice majeure. De ce fait l'acide acétique de pKa supérieur au pKa de l'acide lactique, a un pouvoir inhibiteur supérieur. Les activités inhibitrices du diacétyle, de l'acétaldéhyde et des acides aminés de forme isomérique D sont décrites bien que leurs effets soient mineurs dans les fermentations lactiques habituelles. Les bactériocines produites par certaines bactéries lactiques seront décrites dans une seconde revue.
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Enrichment culture techniques produced more than 1200 isolates of lactic acid bacteria (LAB) that were screened for antifungal activity against the indicator mould Aspergillus fumigatus. Approximately 10% of the LAB were active, but only 4% had medium or strong activity in an agar plate assay. The majority of isolates with strong antifungal activity were Lactobacillus coryniformis strains, but Lactobacillus plantarum and Pediococcus pentosaceus were also frequently identified. Some of the isolates lost activity during storage but most maintained their fungal inhibitory effect. Large variations in sensitivity were observed between different moulds and yeasts. Antifungal cyclic dipeptides and phenyllactic acid were detected in culture filtrates from several of the LAB isolates. Lactobacillus coryniformis subsp. coryniformis strain Si3 produced an antifungal compound that lost activity when treated with proteinases. The antifungal peptide(s) was heat stable, with a size of approx. 3kDa and had maximum activity at pH 3.0 to 4.5. Addition of ethanol to the growth medium of strain Si3 prevented a decline in observed antifungal activity during the stationary phase. Glycerol addition to agar plates with L. coryniformis strains, overlaid with soft agar suspensions of yeast cells or fungal spores, strongly enhanced the antifungal effect. This was particularly true with spoilage moulds and yeasts, e.g. Penicillium roqueforti and Pichia anomala, not normally affected by the antifungal metabolites of L. coryniformis. Chemical and genetic data suggested that reuterin (3-hydroxypropionaldehyde) was the cause of this effect. The glycerol/diol dehydratase operon of L. coryniformis was partially elucidated and found to be similar to that Lactobacillus collinoides. Bioassay-guided isolation of new metabolites from LAB revealed that Lactobacillus plantarum MiLAB 14 produces hydroxylated fatty acids with strong antifungal effects. 3-Hydroxydecanoic acid, 3-hydroxydodecanoic acid, 3-hydroxytetradecanoic acid and 3-hydroxy-5-cis-dodecenoic acid were characterized from the supernatant of MiLAB 14. The hydroxy fatty acids had total inhibitory effects in the range 10 to >100 µg ml-1 against several moulds and yeasts.
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The ability of lactic acid bacteria (LAB) to bind fumonisins B1 and B2 (FB1, FB2) in fermented foods and feeds and in the gastrointestinal tract could contribute to decrease their bioavailability and toxic effects on farm animals and humans. The aim of this work was to identify the bacterial cell wall component(s) and the functional group(s) of FB involved in the LAB-FB interaction. The effect of physicochemical, enzymatic and genetic treatments of bacteria and the removal/inactivation of the functional groups of FB on toxin binding were evaluated. Treatments affecting the bacterial wall polysaccharides, lipids and proteins increased binding, while those degrading peptidoglycan (PG) partially decreased it. In addition, purified PG from Gram-positive bacteria bound FB in a manner analogue to that of intact LAB. For FB, tricarballylic acid (TCA) chains play a significant role in binding as hydrolysed FB had less affinity for LAB. Peptidoglycan and TCA are important components of LAB and FB, respectively, involved in the binding interaction. Lactic acid bacteria binding efficiency seems related to the peptide moiety structure of the PG. This information can be used to select probiotics with increased FB binding efficiency.