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Antifungal activity of sulfur-containing salts against the development of carrot cavity spot and potato dry rot
Abstract
In the search for alternatives to synthetic fungicides to control postharvest disease, sulfur-containing salts were evaluated for their effects on the mycelial growth of various fungal or fungus-like pathogens and their ability to control carrot cavity spot (Pythium sulcatum) and potato dry rot (Fusarium sambucinum). Results showed that metabisulfite-containing salts provided strong inhibition of all the tested fungi. Furthermore, some sulfate-containing salts were also directly inhibitory to P. sulcatum (calcium sulfate and ammonium sulfate) and to F. sambucinum (sodium sulfate). The metabisulfite salts also provided 100% inhibition of cavity spot and dry rot at concentrations of 50 and 200 mM, respectively. Calcium sulfate and sodium sulfate also significantly reduced carrot cavity spot lesions at 50 mM and ammonium sulfate, magnesium sulfate, potassium sulfate and sodium sulfate reduced potato dry rot lesions at 200 mM. These results indicate that various sulfate and metabisulfite salts could be used to control these postharvest microorganisms.Highlights► Sulfur-containing salts inhibited growth of pathogens in vitro. ► Sulfur-containing salts inhibit carrot and potato disease. ► Metabisulfite-containing salts were most effective. ► Sulfate-containing salts were effective against specific fungi and postharvest diseases.
... Among them, post-harvest diseases induced by fungal pathogens cause significant economic losses worldwide [3,4]. For instance, early or late blight, Verticillium wilt, and powdery scab, especially dry rot as one kind of most serious postharvest diseases which causes 6%-60% yield loss annually and mainly infested by single or multi kinds of Fusarium [5]. There are reported 13 species associated with Fusarium dry rot worldwide [6] and Bojanowski et al. [7] isolated the predominant pathogens of F. oxysporum and F. avenaceum in China. ...
... and highest inhibition rate exhibited on F. sambucinum and lowest in F. oxysporum (85.3 and 54.7%). Kolaei et al. [5] pointed out that metabisulfite salts inhibited all selected fungi and 200 mM capable inhibit dry rot 100%. Regarding S61 extracts, the inhibition rates of the three pathogens improved with the increased concentration (5.0-40.0 ...
... Elsherbiny et al. [9] perform methanol extraction of pomegranate peel demonstrated remarkable activity on F. sambucinum inhibition with 23.7-75.5% from 1.25-20 mg/ml concentration, greatest in 20 mg/ml to prevent potato dry rot. Kolaei et al. [5] identified there was no effect of organic solvents dichloromethane, chloroform, and ethyl acetate on antimicrobial activity while ethyl acetate extract has higher recovery and activity. The current study exhibited that Halobacillus trueperi S61 and its active extracts could inhibit the growth of pathogens, the ethyl acetate extract had the highest activity and the strongest inhibitory activity of S61 was acting on Qing 9A-1-1 (Fusarium tricinctum). ...
This study investigated the inhibitory activity of Halobacillus trueperi S61 and its active extract on potato dry rot pathogens and aimed at contributing to biocontrol agent development during potato storage. Three kinds of pathogens were isolated as target pathogenic fungi from dry rot tubers and determined as Fusarium acuminatum (Qing 9A-2), Fusarium equisetai (Qing 9A-5-8) and Fusarium tricinctum (Qing 9A-1-1) by morphological and molecular identification. The strain Halobacillus trueperi S61 and its extract exhibited a higher inhibitory rate on both three pathogens (56.32–65.75 and 1.67–51.11%), notably the best suppression efficiency is presented in Halobacillus trueperi S61 and 40 mg/mL ethyl acetate extract. In terms of in vivo effects, both Halobacillus trueperi S61 and its ethyl acetate extract effectively reduced the decayed fruit and weight loss rate (0–20% and 7.59–16.56%) and enhanced the defensive enzymatic activities to improve resistance. In addition, strain S61 could be colonized on potato tubers, especially the highest amount of 1.55 × 10⁷ CFU/mL on fifth day for variety Xiazhai 65. Overall, Halobacillus trueperi S61 and its ethyl acetate extract could be considered as potential approach for biocontrol potato dry rot.
... Sulfur-containing salts have been tested both in vitro and in vivo against several pathogens of commercial importance on crops such as the potato, carrot, and citrus fruits [29][30][31][32][33][34][35], but, to our knowledge, these salts have not been evaluated for the control of major postharvest diseases of stone fruit. Therefore, the objectives of this study were to (i) evaluate the effect of various sulfur-containing salts, at different concentrations, on the in vitro mycelial growth of three major stone fruit postharvest pathogens (M. ...
... For example, SMBS and PMBS, both at 10 mM, completely inhibited the mycelial growth of Alternaria solani Sorauer, B. cinerea, and R. stolonifer (pathogens causing decay of eggplant, pepper, and tomato, among other horticultural products), Fusarium sambucinum Fuckel (causing potato dry rot), and Pythium sulcatum R.G. Pratt & J.E. Mitch. (causing carrot cavity spot) [30]. Similarly, in another study by the same authors, the salt AlS at 1 mM inhibited the mycelial growth of A. solani, B. cinerea, F. sambucinum, and R. stolonifer and reduced above 60% the development of P. sulcatum, whereas AlPS reduced by more than 80% the mycelial growth of B. cinerea [31]. ...
... Some inorganic or organic salts, such as benzoates, sorbates, and carbonates, have been previously reported as effective to some extent in controlling major postharvest diseases of stone fruit [17,19,20,36,37]. Moreover, sulfur-containing salts have been tested both in vitro and in vivo against several pathogens of commercial importance in crops such as the potato, carrot, and citrus [29][30][31][32][33][34][35], but, to our knowledge, this is the first work evaluating its use for the control of major postharvest diseases of stone fruits. Thus, the present paper is the first report on the potential curative activity of metabisulfite-containing salts, namely SMBS and PMBS, to control BR. ...
The sulfur-containing salts, classified as food additives, sodium metabisulfite (SMBS), potassium metabisulfite (PMBS), aluminum sulfate (AlS), and aluminum potassium sulfate (AlPS), were evaluated for their activity against Monilinia fructicola, Rhizopus stolonifer, and Geotrichum candidum, the most economically important fungal pathogens causing postharvest disease of stone fruit. In in vitro tests with potato dextrose agar (PDA) Petri dishes amended with different concentrations of the salts (0, 10, 20, 30, 50, and 100 mM), SMBS and PMBS at all concentrations, AlS above 20 mM, and AlPS above 30 mM, completely inhibited the mycelial growth of the three fungi after incubation at 25 °C for up to 10 days. In in vivo primary screenings with artificially inoculated nectarines, aqueous solutions of the four salts reduced the incidence and severity of brown rot (BR) at concentrations of 10 and 50 mM, whereas only AlS and AlPS reduced Rhizopus rot (RR), and none of the salts was effective against sour rot (SR). Solutions at 100 mM were phytotoxic and injured the fruit peel. In small-scale trials, 1 min dip treatments at 20 °C in SMBS or PMBS at 10 mM significantly reduced the incidence and severity of BR after incubation at 20 °C for up to 8 days. Conversely, dips in AlS and AlPS reduced neither BR nor RR. Results highlight the potential of SMBS and PMBS as new nonpolluting tools for the integrated control of BR, but not RR and SR, on stone fruit.
... • The minimum inhibitory concentration on mycelial growth varied between 1 and 10 mM in vitro. Kolaei et al. (2012) Sulfur-containing salts • Carrots were dipped in solutions with sulfur-containing salts. ...
... The fungistatic effects of inorganic salts have been previously reported (Kolaei et al., 2012(Kolaei et al., , 2013. Inorganic salts (i.e., aluminum sulfate, potassium metabisulfite etc.) have been used in the food industry as preservatives and antimicrobial agents. ...
... In vitro experiments have shown the potential of inorganic salts to control B. cinerea. Specifically, sodium and potassium metabisulfite salts at a concentration of 10 mM and aluminum sulfate salts at a concentration of 1 mM showed strong in vitro inhibition growth activity of B. cinerea (Kolaei et al., 2012(Kolaei et al., , 2013. The antifungal activity of metabisulfite salts has been attributed to the sulfur dioxide (SO 2 ) which is liberated and interacts with different cell components (i.e., structural proteins or enzymes) through cleavage of disulfide bonds. ...
Background: Carrot is one of the most important horticultural crops, with an annual worldwide production exceeding 40 million tonnes. Carrots are sold either fresh intact or fresh-cut as minimally processed vegetables (MPV). In the postharvest supply chain, physiological disorders, fungal decay, and their combinations reduce the quality of fresh intact and MPV carrots. MPV carrots are more susceptible to quality changes than fresh intact carrots due to a higher loss of protective epidermis, greater number of wounded cells, and increased respiration rates. Scope and approach: The current review summarizes different environmentally and human-friendly treatments applied in the postharvest supply chain to minimize the adverse effects of handling and storage on physiological disorders and fungal decay. Key findings and conclusions: Bitterness, white blush, and browning are the most critical physiological disorders of fresh and MPV carrots. Bitterness can be prevented by storing carrots in well-ventilated rooms without ethylene- producing fruit and vegetables, while white blush and browning can be controlled by the application of heat treatment, ultraviolet (UV)-irradiation, hydrogen sulfide (H2S), and edible films. Sclerotinia sclerotiorum, Botrytis cinerea, Alternaria radicina, and Berkeleyomyces spp. (formerly Thielaviopsis spp.) are important fungi causing carrot postharvest losses and waste. Fungal decay of carrots can be controlled by selecting healthy carrots and applying natural compounds, ozone (O3), heat treatment, UV-irradiation, inorganic salt, and/or biocontrol agents, and their combinations. However, a successful combination of different sustainable treatment methods requires treatment compatibility, and -omics techniques may reveal the best combinations of sustainable treatment methods.
... Many studies have demonstrated the potential of GRAS salts, such as carbonates, bicarbonates, sorbates, benzoates, parabens, etc. to control postharvest diseases of citrus fruits as both aqueous solutions and ingredients of edible coatings (Askarne et al., 2013;Guimarães et al., 2019;Montesinos-Herrero et al., 2016;Moscoso-Ramírez et al., 2013;Palou et al., 2002;Smilanick et al., 2008;Valencia-Chamorro et al., 2009). In previous studies, the antifungal activity of a variety of sulfurcontaining salts was shown to include pathogens causing disease on important crops such as potato or carrot (Hervieux et al., 2002;Kolaei et al., 2012;Mecteau et al., 2008;Mills et al., 2004). The status as food additives of a group of sulfur-containing compounds included in these studies, the aluminum sulfate group (E-numbers: E 520-523), was reevaluated in 2018 by the EFSA and the Panel concluded that these compounds are of no safety concern in the current authorized uses and use levels, which now include only egg products and breath freshening micro-sweets (EFSA, 2018). ...
... SMBS and PMBS are used as preservatives. AlS and AlPS are permitted for multiple purposes; both are used as firming and pH-adjusting agents and AlS is also used as a starch modifier (Health Canada, 2017;Kolaei et al., 2012Kolaei et al., , 2013US FDA, 2019). Herein, we evaluated the activity of these salts to inhibit the mycelial growth of P. digitatum, P. italicum and G. citri-aurantii and afterwards their ability to control citrus GM, BM and SR. ...
... Sulfur-containing salts have previously shown good activity in in vitro tests against different postharvest pathogens affecting important crops. Indeed, it has been reported that SMBS affected the in vitro spore germination of B. cinerea (Alaoui et al., 2017;Mills et al., 2004) and inhibited the mycelial growth of pathogenic fungi such as Alternaria solani (Kolaei et al., 2012), Fusarium sambucinum (Kolaei et al., 2012;Mecteau et al., 2002), Fusarium solani var. coeruleum (Mecteau et al., 2008), Helminthosporium solani (Hervieux et al., 2002), Pythium sulcatum and Rhizopus stolonifer (Kolaei et al., 2012). ...
Sodium metabisulfite (SMBS), potassium metabisulfite (PMBS), aluminum sulfate (AlS) and aluminum potassium sulfate (AlPS), common sulfur-containing salts used as food additives, were evaluated for their antifungal activity against Penicillium digitatum, Penicillium italicum and Geotrichum citri-aurantii, the most economically important pathogens causing postharvest diseases of citrus fruits. In vitro radial mycelial growth was measured on potato dextrose agar (PDA) Petri dishes amended with five different concentrations of the salts (10, 20, 30, 50, 100 mM) after 7 d of incubation at 25 °C. SMBS and PMBS at all concentrations, and AIS and AIPS above 20 mM, completely inhibited the growth of these fungi. The curative antifungal activity of the four salts to control citrus green (GM) and blue (BM) molds and sour rot (SR) was evaluated on ‘Valencia’ oranges artificially inoculated in rind wounds with P. digitatum, P. italicum and G. citri-aurantii, respectively. In vivo primary screenings showed no significant antifungal activity of AlS and AlPS to control the three diseases at any dose tested, but SMBS and PMBS reduced the incidence and severity of GM, BM and SR at various concentrations. Effective salts and concentrations were selected for in vivo dip treatments in small-scale trials. Dips at room temperature (20 °C) in SMBS and PMBS at 20 and 50 mM for 60 or 120 s significantly reduced the incidence and severity of GM and BM, with PMBS at 50 mM for 120 s the most effective treatment. Conversely, dips in SMBS and PMBS at 50 mM for 60 or 120 s did not reduce SR incidence and severity. SMBS and PMBS treatments are potentially new tools to be included in reduced-risk non-polluting strategies to control Penicillium diseases, but not SR, on citrus fruits.
... Several organic and non-organic salts were shown to inhibit mycelial growth and spore germination of F. sam- bucinum and F. solani var. coeruleum in vitro ( Mecteau et al., 2002Mecteau et al., , 2008Kolaei et al., 2012). Among these salts, potassium metabisul- fite and sodium metabisulfite provided 100% inhibition of dry rot under laboratory conditions ( Kolaei et al., 2012). ...
... coeruleum in vitro ( Mecteau et al., 2002Mecteau et al., , 2008Kolaei et al., 2012). Among these salts, potassium metabisul- fite and sodium metabisulfite provided 100% inhibition of dry rot under laboratory conditions ( Kolaei et al., 2012). Ammonium sul- fate, magnesium sulfate, potassium sulfate, sodium sulfate, sodium carbonate, sodium bicarbonate, aluminum chloride, and calcium and potassium phosphites also reduced significantly the disease under laboratory conditions ( Mecteau et al., 2002Mecteau et al., , 2008Lobato et al., 2008;Kolaei et al., 2012). ...
... Among these salts, potassium metabisul- fite and sodium metabisulfite provided 100% inhibition of dry rot under laboratory conditions ( Kolaei et al., 2012). Ammonium sul- fate, magnesium sulfate, potassium sulfate, sodium sulfate, sodium carbonate, sodium bicarbonate, aluminum chloride, and calcium and potassium phosphites also reduced significantly the disease under laboratory conditions ( Mecteau et al., 2002Mecteau et al., , 2008Lobato et al., 2008;Kolaei et al., 2012). The use of salts in postharvest treatments could eventually constitute an interesting alterna- tive to synthetic chemical fungicides as many salts are generally recognized as safe (GRAS) and used in food processing indus- try. ...
Dry rot is a postharvest fungal disease affecting potato (Solanum tuberosum L.) tubers. The disease, caused by several species of Fusarium such as F. solani var. coeruleum, F. sambucinum, F. oxysporum, F. avenaceum, F. culmorum, results in significant yield losses. Some Fusarium species associated with the disease produce toxins, which are implicated in mycotoxicoses of humans and animals. The pathogens cannot penetrate the tuber through the lenticels or in the absence of wounds and cause infection only if the potato skin is ruptured. The seed tuber is considered as the main source of inoculum although soil infested by Fusarium spp. also constitutes a source of inoculum. Control of the disease, once provided by the fungicide thiabendazole, is now difficult due to the appearance of thiabendazole-resistant strains and the lack of potato cultivars with high levels of resistance to dry rot. An integrated disease management program including detection strategies, appropriate cultural practices and storage conditions (including a wound healing period) along with the use of synthetic chemical fungicides as seed tuber and/or postharvest treatment is recommended to reduce incidence and severity of dry rot. Recent studies also indicate the possibility that generally recognized as safe (GRAS) compounds and microbial antagonists could eventually be integrated into dry rot management strategies.
... Recently, salt/acid solutions have been suggested as alternative methods for preventing the proliferation of microorganisms in food products [48]. Additionally, ammonium sulfate alone demonstrated the ability to impede the growth of mycotoxigenic fungi [48][49][50][51][52]. The hand sanitizer formulation was enhanced using the addition of a small quantity of povidone-iodine, as povidone-iodine (PVPI) has long been recognized for its efficacy as a broad-spectrum microbicide against bacteria, fungi, protozoans, and viruses [53]. ...
... Azelaic acid has been found to possess significant anti-inflammatory and antioxidative effects, and it exhibits bactericidal activity against a wide range of Gram-negative and Gram-positive microorganisms, including antibiotic-resistant strains [72]. Furthermore, it is worth noting that ammonium sulfate salt has been found to exhibit mild antifungal properties [51]. ...
In light of the global health crisis triggered by the COVID-19 pandemic, numerous experts have deemed the utilization of hand sanitizers imperative as a precautionary measure against the virus. Consequently, the demand for hand sanitizers has experienced a substantial surge. Since the beginning of 2020, the utilization of alcohol-free hand sanitizers has been increasingly favored due to the potential risks associated with alcohol poisoning, flammability, as well as the adverse effects on skin lipid dissolution, dehydration, and sebum reduction, which can lead to severe cases of eczema and norovirus infections. In this study, we developed an aqueous hand sanitizer that does not contain alcohol. The sanitizer consists of naturally occurring, food-grade organic acids, including lactic, citric, and azelaic acids. Additionally, food-grade ammonium sulfate and a small amount of povidone-iodine (PVPI) were included in the formulation to create a synergistic and potent antibacterial effect. The effectiveness of the hand sanitizer was evaluated against four common foodborne pathogens, namely Clostridium botulinum, Escherichia coli, Listeria monocytogenes, and Staphylococcus aureus, via in vitro testing. The organic acids exhibited a synergistic inhibitory function, resulting in a 3-log reduction in CFU/mL. Furthermore, the presence of povidone-iodine and ammonium sulfate enhanced their antibacterial effect, leading to a 4-log reduction in CFU/mL. The hand sanitizer solution remained stable even after 60 days of storage. During this period, the detection of additional triiodide (I3−) ions occurred, which have the ability to release broad-spectrum molecular iodine upon penetrating the cell walls. This alcohol-free hand sanitizer may offer extended protection and is anticipated to be gentle on the skin. This is attributed to the presence of citric and lactic acids, which possess cosmetic properties that soften and smoothen the skin, along with antioxidant properties.
... These salts showed a broad-spectrum of antimicrobial activity with biocompatibility and little human toxicity. Sodium metabisulfite has been reported to be among the most efficient salt to control microbial growth [5]. However, sulfite (SO 3 ) are known to cause sulfite allergies [6]. ...
... However, the other sulfur-containing salt, sodium metabisulfite showed comparably high antimicrobial activity. Kolani et al. [5] also found that sodium metabisulfite has strong antifungal activity, but sodium thiosulfate does not. Elemental sulfur also showed high antimicrobial activity, which is comparable to or higher than sodium metabisulfite. ...
The antimicrobial activity of sulfur nanoparticles (SNPs) was compared with elemental sulfur and sulfur-containing salts (sodium thiosulfate and sodium metabisulfite) against bacteria (Escherichia coli, Staphylococcus aureus) and fungi (Aspergillus flavus, Candida albicans) using the paper disc, broth microdilution, and time-kill assay methods. The results of the paper disc and MIC tests showed stronger antimicrobial activity of SNPs compared to the elemental sulfur and sulfur-containing salts. SNPs showed more potent activity against bacteria than fungi. Among the test microorganisms, E. coli (Gram-negative) was the most susceptible to SNPs, followed by S. aureus (Gram-positive), C. albicans (yeast), and A. flavus (mold). Scanning electron micrographs of microorganisms treated with SNPs showed different cell disruption patterns depending on the type of microorganisms.
... Many studies suggest that these salts may represent a possible alternative to synthetic fungicides [10][11][12][13][14][15]. Recent literature also claims that sodium metabisulfite is among the most efficient salts for controlling plant pathogens [16][17][18][19][20][21][22][23][24]. ...
... Sodium metabisulfite and potassium metabisulfite are used as preservatives. Other sulfur-containing salts (ammonium sulfate, magnesium sulfate, potassium sulfate and sodium sulfate) are used as pH-adjusting agents in foods, which may affect food microbiological quality [12]. There are numerous proposed mechanisms of action for sulfur-containing compounds in inhibiting microorganisms. ...
The efficacies of sulfur-containing salts (ammonium sulfate, magnesium sulfate, potassium metabisulfite, potassium sulfate, sodium metabisulfite and sodium sulfate) were evaluated as possible alternatives to synthetic fungicides for the control of economically important phytopathogenic fungi, including Fusarium culmorum, F. nivale, F. solani, Macrophomina phaseolina, Rhizoctonia solani, Sclerotinia sclerotiorum, Puccinia triticina and Uromyces appendiculatus. The results, including the concentration of salts that caused a 50% reduction (ED50), the minimum inhibition concentration (MIC), and the minimum fungicidal concentration (MEC) values for mycelial growth, spore germination and germ-tube elongation, indicated that sodium metabisulfite, potassium metabisuffite and ammonium sulfate were more toxic to the tested fungi than the other salts. Therefore, sodium metabisulfite and potassium metabisulfite were selected for further testing in soil. Both sodium metabisulfite and potassium metabisulfite completely inhibited the mycelial growth of S. sclerotiorum at 0.2% in soil tests. However, they were able to stop mycelial growth of F. culmorum, F. nivale, F. solani, M. phaseolina and R. solani at only 0.4%. In pot experiments conducted under controlled conditions, foliar sprays of salts at all the concentrations tested except 0.05% were effective on the control of rust fungi (P. triticina and U. appendiculatus). In these experiments, control efficacy of all tested salts ranged from 0 to 90.3% and 0 to 94.9% against P. triticina and U appendiculatus, respectively. Sodium sulfate at 1.5% and Mancozeb treatments equally and effectively reduced the pustules caused by P. triticina and U appendiculatus. The results of this study showed that the sulfur-containing salts tested could be used for control of phytopathogenic fungi.
... Caropak) were surface-sterilized by dipping in a 0.5% solution of sodium hypochlorite for 5 min, rinsed with distilled water, and allowed to air dry. Three wounds were performed on each carrot by scraping the epidermis with a sterile razor blade according to Kolaei et al. (2012). An agar plug (0.5 cm diameter) covered with actively growing mycelium of P. sulcatum was placed directly on each wound. ...
... Cavity spot and dry rot are considered amongst the most prevalent postharvest diseases in carrot roots and potato tubers. Dry rot is mainly controlled by postharvest applications of the fungicide thiabendazole ( Kolaei et al., 2012). There have been numerous reports that show an increase in resistance of F. sambucinum to thiabendazole (Holley and Kawchuk, 1996;Platt, 1997;Peters et al., 2001) that have reduced the efficacy of this fungicide in controlling this disease. ...
As an alternative to the use of synthetic chemical fungicides to control plant disease, aluminium‐containing salts were evaluated for their effects on the mycelial growth of various fungal or fungus‐like pathogens and their ability to control carrot cavity spot (Pythium sulcatum) and potato dry rot (Fusarium sambucinum). Results showed that various aluminium‐containing salts provided strong inhibition of all the tested pathogens (Alternaria solani, Botrytis cinerea, F. sambucinum, P. sulcatum and Rhizopus stolonifer) with minimal inhibitory concentration of 1–10 mM. Aluminium chloride and aluminium sulphate were generally the most effective, inhibiting mycelial growth of pathogens by as much as 47% and 100%, respectively, at a salt concentration of 1 mM. Applied at 5 mM, aluminium sulphate also provided 28% and 100% inhibition of dry rot and cavity spot, respectively. Aluminium chloride (5 mM) reduced dry rot by 25% whereas aluminium lactate (5 mM) decreased cavity spot lesions by 86%. These results indicate that various aluminium‐containing salts may provide an alternative to the use of synthetic fungicides to control these pathogens.
... In vivo antifungal activity of clove or cinnamon oil in combination with acid salts against Alternaria in carrots stored at abusive temperature Fresh mature carrots were washed and sanitized by soaking in 0.5% v/v sodium hypochlorite and rinsing with sterile water. After surface drying, a sterile 4-mm diameter corkborer was used to puncture into the surface of each carrot to make three wounds (3 mm deep each) according to Kolaei et al. (2012) with slightly modification. All punctured carrots were divided into six groups (9 carrots each) for dipping treatments in solutions: T1, control (sterile water); T2, 7,500 ppm chlorothalonil; T3, 0.25% AC mixed with 0.125% cinnamon oil; T4, 0.5% AC mixed with 0.25% cinnamon oil; T5, 0.25% PM mixed with 0.04% clove oil; and T6, 1% AC. ...
Fungal decay in carrots is a serious problem during postharvest storage. The present work aimed to study the antifungal effect of ammonium carbonate (AC) or potassium metabisulfite (PM) in combination with cinnamon or clove oils on delaying carrot decay caused by black rot mold during chill storage. In vitro trials were conducted to determine the antifungal activity of those acid salts, essential oils and their combinations against selected fungi isolated from carrots. Alternaria sp. C7D7 isolated from carrots was inhibited by AC and PM at 0.5-1.0% w/v minimum inhibitory concentration (MIC), while cinnamon and clove oils possessed strong anti-Alternaria effect with 0.025% w/v MIC. The combination of AC or PM at 0.25-0.5% w/v with cinnamon or clove oils at 0.04-0.25% w/v in potato dextrose agar produced a 100% antifungal index. Synergy testing by the checkerboard method showed that the combination of AC and cinnamon oil had partial synergistic effects against the mold. The optimum concentrations of combined AC or PM and cinnamon or clove oil were selected to formulate dipping solutions for carrot treatments. Their effect on controlling black rot decay in carrots during chill storage was investigated. The treatment with the dipping solutions consisting of combined 0.5% AC with 0.25% cinnamon oil or 1% AC alone caused a lower percentage of black rot decay (13.9-19.4% decay) in carrots compared to the others during storage at 5°C for 10 weeks. These findings show the usefulness of cinnamon oil and AC or their combination on delaying black rot decay in carrots.
... Recognised As Safe (GRAS) and reported as antifungal, antioxidant, and reducing agent in the food industry [10,16]. ...
Pomegranate is of considerable economic significance, with Maharashtra, Karnataka, and Gujarat serving as the primary cultivation regions. In spite of the high production levels, postharvest losses are serious, with certain fruits experiencing fruit cracking, fungal infections, and poor handling during transportation, resulting in postharvest losses of up to 35%. Therefore, the present investigation examined the effectiveness of VeSolution in reducing these losses. The investigation entailed the isolation and identification of fungal pathogens from pomegranates that were infected. Aspergillus sp., Alternaria sp., and Coinella sp. were identified as the fungi that were associated with pomegranate fruit rotting. Following this, VeSolution's antifungal properties were assessed in vitro and in vivo. The results indicated that the growth of fungal colony was substantially inhibited by the 2% and 5% concentrations of VeSolution. The fruits rot development and progression were effectively restricted by the 2% VeSolution, as confirmed by in vivo assessments. Subsequent pilot and large-scale trials demonstrated that 1% VeSolution substantially reduced rot during longer transportation periods, thereby retaining the quality and reducing fruit rotting for up to 84 hours. These results emphasis VeSolution as a viable and non-toxic alternative to conventional synthetic fungicides for maintaining the postharvest quality of pomegranates.
... Since that time, other research works have been carried out on SMBS against a wide spectrum of microorganisms including viruses, bacteria, fungi, algae and cancer cells 13,14 . It was also reported to stop the growth of silver scurf, dry rot and soft rot in potato [15][16][17][18][19] carried out research on the effect of foliar application of SMBS on pink rot and leaf blight of potatoes in which they suggested that SMBS has potential as an alternative to currently labelled chemical fungicides for controlling crop fungal disease. ...
Background and Objective: Maize, a vital cereal crop globally, faces challenges from foliar diseases like
common rust, impacting yield and quality. This study assesses the efficacy of sodium metabisulphite salt
(SMBS) in controlling common maize rust caused by Puccinia sorghi and its impact on Wistar rat health.
It aims to offer insights into SMBS as a sustainable alternative to chemical fungicides by evaluating disease
incidence and monitoring rat health post-consumption. Materials and Methods: A study at the Institute
of Agricultural Research and Training, Obafemi Awolowo University, Ibadan, assessed SMBS for maize
disease management and safety. Two maize varieties, ART/98/SW5-OB and T2BR-ELDB, received SMBS
treatments (10 and 15 g/L) at different growth stages in a Randomized Complete Block Design with three
replications. Disease incidence, severity and agronomic traits were analysed using ANOVA and Duncan’s
Multiple Range Test at p<0.05. Results: The results indicated that SMBS application significantly promoted
plant growth, as evidenced by increased plant height, leaf number and leaf area with a significant
reduction in incidence and severity of common rust disease in maize plants studied, highlighting its
potential as a protective agent against fungal infections in crops. However, variations in the responses of
different maize varieties to SMBS were observed. The acute toxicity of SMBS was also assessed on Wistar
rats as they were exposed to varying doses of SMBS through the consumption of maize leaves and the
powdered form. The results demonstrated that SMBS did not cause any significant adverse reactions and
death in the rats at the tested doses, indicating a relatively low acute toxicity in this animal model.
Conclusion: The study confirms SMBS as a promising dual-purpose agent for maize disease control and
growth promotion, demonstrating its safety and efficacy, thus advancing sustainable agricultural practice
... [9] There are also developments in terms of its use as bactericidal and fungicidal agents necessary for combating agricultural pests. [10] More than 2500 Antimicrobial peptides have been identified and isolated from natural sources. Compared to conventional antibiotics, Antimicrobial peptides exhibit antimicrobial activities against a broad spectrum of microorganisms including bacteria, fungi, and even viruses. ...
Sulfur is an abundantly available biologically active element and has been used for a long time as a bactericidal and fungicidal
drug in both medical, veterinary and in agricultural practices. Synthesized hydrophilic sulfur nanoparticles can potentially
allow the delivery of high concentrations of sulfur to infections. In the present study, a quick and environmentally friendly
approach has been developed for the synthesis of hydrophilic sulfur nanoparticles with antibacterial activity. Hydrophilic
sulfur nanoparticles (SNPs) were prepared by modifying the surface of elemental sulfur by various water-soluble surfactants
including hexadecyltrimethylammonium bromide (CTAB), sodium dodecyl benzene sulfonate (SDBS) and Triton X-100 (TX-
100). The hydrophilic SNPs were characterized by UV–visible spectrophotometer, X-ray diffraction (XRD), and
thermogravimetric analysis (TG/DSC), scanning electron microscope (SEM), the hydrophilic SNPs showed an almost spherical
shape with an average size in the range of 150-200 nm. The antibacterial activity of the hydrophilic sulfur nanoparticles was
tested using against Gram-positive (S. aureus and E. faecium) and Gram-negative (E. coli and P. aeruginosa) bacteria. As a
result, that hydrophilic SNPs exhibited significant antimicrobial activity against Gram-positive bacteria, i.e., S. aureus and E.
faecium. The acute toxicity of the hydrophilic SNPs was studied at a single oral administration of solutions of hydrophilic SNPs,
as a result of the study of hydrophilic SNPs, it was determined as a non-toxic substance. The received products can be
considered as perspective forms of application in agriculture and medicine.
... Inhibitory activity on spore germination of A. aculeatus and P. citrinum was high at 6.30 and 6.44 log CFU/mL, respectively. Ref. [25] reported that sodium metabisulfite has strong antifungal activity. B. cereus treated with 10% (w/v) KMS solution for 10 min showed significant reduction compared with treatments of 1, 2.5, 3 and 5% (w/v). ...
This study investigated the inhibitory activity of organic solutions containing 5, 10, 15, 20 and 30% (w/v) sodium chloride and citric acid solution and 15:10, 15:15, 15:20 and 15:30% (w/v) sodium chloride (NaCl) combined with citric acid (CA) solution (salt/acid solution) for 10 min against microorganisms isolated from trimmed young coconut: Bacillus cereus, B. subtilis, Staphylococcus aureus, S. epidermidis, Enterobacter aerogenes, Serratia marcescens, Candida tropicalis, Lodderromyces elongisporus, Aspergillus aculeatus and Penicillium citrinum. Commercial antimicrobial agents such as potassium metabisulfite and sodium hypochlorite (NaOCl) were used as the controls. Results showed that 30% (w/v) NaCl solution displayed antimicrobial properties against all microorganisms, with s reduction range of 0.00–1.49 log CFU/mL. Treatment of 30% (w/v) CA solution inhibited all microorganisms in the reduction range of 1.50–8.43 log CFU/mL, while 15:20% (w/v) salt/acid solution was the minimum concentration that showed a similar antimicrobial effect with NaOCl and strong antimicrobial effect against Gram-negative bacteria. The mode of action of this solution against selected strains including B. cereus, E. aerogenes and C. tropicalis was also determined by scanning electron microscopy and transmission electron microscopy. B. cereus and E. aerogenes revealed degradation and detachment of the outer layer of the cell wall and cytoplasm membrane, while cytoplasmic inclusion in treated C. tropicalis cells changed to larger vacuoles and rough cell walls. The results suggested that a 15:20% (w/v) salt/acid solution could be used as an alternative antimicrobial agent to eliminate microorganisms on fresh produce.
... Sulfite is a substance that naturally occurs in human body and in many foods such as wine (Ulca, Oeztuerk, & Senyuva, 2011) and dried potato products (Kolaei, Tweddell, & Avis, 2012). As regulated food additives, sulfites have been extensively used in food processing and production since sulfites prevent food spoilage, inhibit food oxidation, and retard microbial growth (Mcweeny, Biltcliffe, Powell, & Spark, 1969;Sayavedra-Soto & Montgomery, 2010). ...
Sulfite is a restricted food additive in various food preservatives. In our previous study, the sulfite was effectively removed by casein in shrimp samples. In this paper, the possible desulfite mechanism were explored by examining the interaction of casein with sulfite by fluorescence quenching spectroscopy, Ultraviolet (UV) adsorption, Fourier transform infrared (FTIR) and circular dichroism (CD) spectroscopy. The binding constant (KS), binding thermodynamics, and the interaction effect on the casein’s conformation were investigated. The results showed that casein bound with sulfite via hydrophilic and hydrophobic interactions, with Ks values of 1.07 × 10⁵ at 293 K and 2.78 × 10⁴ at 307 K respectively. The secondary structures and the conformation of casein were changed due to the interaction between casein and sulfite, with a decrease in positive Cotton effect, indicating the casein-sulfite interaction reduced the structural stability of β-sheet folding of casein. As a result, this work provides the theoretical basis for the desulfite mechanism for the sulfite removal by casein in food processing.
... Ginseng anthracnose caused by Colletotrichum gloeosporioides is also suppressed by treatment with lime sulfur diluted 400 times (Lim et al., 2015). Sulfur containing salts can also inhibit postharvest diseases such as carrot cavity spot caused by Pythium sulcatum and potato dry rot caused by Fusarium sambucinum (Kolaei et al., 2012). Likewise, disease sever- ity caused by D. citri on citrus leaves was decreased by pretreatment with bio-sulfur in the present study (Fig. 3), suggesting that bio-sulfur could be a candidate substance as a new fungicide. ...
Melanose, caused by Diaporthe citri, is one of severe diseases in citrus, a major economic resource in Jeju island. To reduce the usage amount of organic synthetic fungicide, bio-sulfur was tested as an alternative chemical to control citrus melanose in the present study. Direct antifungal activity of bio-sulfur against D. citri was determined through in vitro experiment using artificial nutrient media. Disease severity of melanose on bio-sulfur pretreated citrus leaves was lower than that on untreated ones. To illustrate the mechanism of disease suppression by bio-sulfur, infection structures were observed with a fluorescent microscope and a scanning electron microscope. In fluorescent microscopic observation, most conidia rarely germinated. In addition, hyphal growth on leaves pretreated with bio-sulfur was inhibited compared to that on untreated ones. In scanning electron microscope images of bio-sulfur pretreated leaves, surfaces of most conidia were shrunk while hyphae were morphologically changed and frequently branched. Such microscopic observations were also found for leaves pretreated with a commercial fungicide Dithianon. These results suggest that bio-sulfur may be used to control citrus melanose as an environment friendly alternative to organic synthetic fungicides.
... Sulfurous acid salts do possess some antifungal properties. Kolaei, Tweddell, and Avis (2012) found sulfur containing salts to effectively control postharvest fungal rots on carrot. Acetic acid has some antimicrobial properties (Sholberg, Haag, Hocking, & Bedford, 2000). ...
Effect of drying (solar and oven), blanching (steam and water), and chemical pretreatments (lemon juice, vinegar, and potassium bisulfite) on oyster mushroom (Pleurotus ostreatus) quality was studied. Total phenolic content, total flavonoid content, ergothioneine, oxygen radical absorbance capacity, moisture, mineral content, protein, and mold infestation were evaluated. Ergothioneine and total phenolics were lower in blanched mushrooms compared to un‐blanched ones. Total flavonoids were highest in water blanched (2.87 ± 0.32–5.98 ± 0.41 mg/g, dry wt.) and least in un‐blanched mushrooms (1.16 ± 0.16–0.3.46 ± 0.3 mg/g, dry wt.). Among the chemical pretreatments, higher total phenolics were observed with vinegar and potassium bisulfite treatments. Blanching resulted in lower K, Mg, Na, S, and P content. Mineral nutrients varied with chemical pretreatments. Blanching followed by either lemon juice or no chemical treatment resulted in high mold infestation. Among the un‐blanched samples, those treated with vinegar had the least mold. Drying method, blanching, and chemical pretreatments affect oyster mushroom quality as demonstrated in this study.
Practical applications
This study focuses on drying and pretreatment methods that can be adopted in resource limited environments. The study shows no difference in the observed nutritional attributes of solar and oven dried mushroom, hence where solar energy is the only option for drying, there is no consequence incurred. While commercial processors have access to several preservation treatments, this may not be so for the subsistence producer. The use of lemon juice, vinegar, or blanching would be inexpensive thus practical even where resources are limited. Since mushroom consumers place much value nutritional and antioxidant properties, knowledge of how these simple inexpensive preservation methods may affect these quality characteristics may help inform preservation decisions.
... coereuleum, and had a strong inhibitory activity on spore germination of F. sambucinum. Furthermore, there has been considerable interest in the use of sulfur-containing salts were evaluated for their effects on the mycelial growth of various fungal or fungus-like pathogens and their ability to control carrot cavity spot caused by Pythium sulcatum and potato dry rot caused by Fusarium sambucinum (Kolaei et al., 2012). They added that calcium sulfate and ammonium sulfate as well as sodium sulfate were directly inhibited P. sulcatum and F. sambucinum, in respective order. ...
Biocontrol agent Trichoderma harzianum and fungicide alternatives as chemical inducers; Calcium sulfate, Cystiene, Disodium phosphate, Potassium metabisulphite, Potassium aluminium sulfate (potash alum) and Sodium sulfate were evaluated individually in combination for their suppressing effect against rust disease incidence and severity under natural field conditions. All applied treatments revealed high response against disease incidence and severity comparing with untreated control. Rust disease incidence at individual application with chemical inducers ranged between 9.6% up to 12.6% comparing with 33.6% at control treatment. More efficient influence was observed when these chemicals combined with the bioagent T. harzianum and revealed disease incidence between 7.6% up to 10.3%. Rust disease incidence at the fungicide Mancozeb treatment was recorded as 19.3% comparing with untreated control 33.6% with reduction efficacy calculated as 58.6%. Similar trend was observed concerning disease severity of faba bean plants, whereas single spray treatment with T. harzianum showed the lowest record followed by applied treatments of chemical inducers combined with T. harzianum. A significant reduction in rust incidence and severity of faba bean under field trials was achieved using integrated treatment application of chemical inducers with the bioagent T. harzianum. It may be concluded that such treatments are considered applicable, safe and cost-effective method for controlling such foliar diseases. © 2018 ISISnet: Innovative Scientific Information Services Network. All rights reserved.
... Other authors [13,20] observed an inhibitory effect of Basfoliar 12-4-6 on the development of the causal agent of early blight. Kolaei et al. [21] noted an inhibitory effect of calcium sulfate and ammonium sulfate on the development of Fusarium sambucinum in potatoes. The species C. coccodes dominated in the control treatment and in the Basfoliar 12-4-6 treatment (ca. ...
Fungal communities colonizing the stems of three potato cultivars fertilized with Basfoliar 12-4-6, ADOB Mn, and Solubor DF were analyzed in the present study. The response of eight fungal potato pathogens (Alternaria alternata, Colletotrichum coccodes, Fusarium concolor, F. culmorum, F. oxysporum, F. solani, Helminthosporium solani, and Rhizoctonia solani) to the above foliar fertilizers added to the PDA medium at the following concentrations: 10, 100, 500, 1,000, and 10,000 mg·dm-3 was determined during in vitro tests. The predominant fungal species isolated from potato stems were Colletotrichum coccodes (Basfoliar 12- 4-6 treatment and control treatment) and Alternaria alternata (ADOB Mn and Solubor applied in combination). Fungi showing antagonistic activity against pathogens had a low share of the fungal community. Foliar fertilizers added to the PDA medium at the studied concentrations significantly inhibited the mycelial growth of A. alternata, C. coccodes, F. solani, and R. solani. F. concolor, F. culmorum, H. solani, and F. oxysporum grown on the PDA medium containing ADOB Mn were least sensitive to the applied fertilizers. Solubor DF had the most toxic effect on fungal pathogens - when applied at the highest concentration, it almost completely suppressed the mycelial growth of pathogenic fungi, except for A. alternata and F. concolor.
... Sulfurous acid salts do possess some antifungal properties. Kolaei, Tweddell, and Avis (2012) found sulfur containing salts to effectively control postharvest fungal rots on carrot. Acetic acid has some antimicrobial properties (Sholberg, Haag, Hocking, & Bedford, 2000). ...
Oyster mushrooms (Pleurotus ostreatus) are the second most widely grown mushrooms in the world, valued for their monetary worth, medicinal properties, nutritional quality and unique flavor. Oyster mushroom production does not require high technology or large capital investment thus it has potential to help improve livelihoods in resource limited communities. However, a major drawback is that oyster mushrooms are highly perishable. Most research has been focused on preservation methods that are more adoptable to large scale operation than household production. While reports on sensory quality evaluations are available, studies on nutritional changes associated with postharvest treatments are largely lacking. There is need for simple and efficient preservation methods that can maximize quality and be easily adopted at household level, especially in communities where food availability and nutrition are a constant challenge. An experiment was conducted to evaluate the effectiveness of postharvest treatments and drying methods on the nutritional quality of oyster mushrooms. Two drying treatments (oven and solar), three blanching treatments (water, steam, and no blanching) and four chemical pretreatments (lemon juice, vinegar, potassium bisulfite, and no chemical) were evaluated. The experiment was laid out in a randomized complete block design with factorial arrangement. Dried mushrooms were evaluated for minerals, ergothioneine, protein, and antioxidant capacity. Analysis of variance was made (SAS program) with least significant differences used to separate means. Blanching and chemical treatment were shown to reduce the protein content. Higher K, Mg, Mn, P, Na, and Fe were found in the steam blanched and non-blanched mushrooms when compared to the water blanched mushrooms. Higher Ca, Mg, Na, and P were found in mushrooms treated with lemon and vinegar when compared with potassium bisulfite, while higher Zn was found with the potassium bisulfite treatment. No differences in mineral content were observed between the solar and oven dried mushrooms.
Introduction
Synthesis of NiO nanoparticles using environmentally friendly Pongamia pinnata seeds as a source of fuel was demonstrated using a solution combustion approach.
Method
The protocol for the synthesis of NiO NPs is simple and efficient. NiO NPs were utilized as the catalyst for the synthesis of N-protected aminoalkyl sulfides from N-protected alkyl thiols and bromo esters of amino acids.
Results
The NiO NPs were characterized using XRD, SEM, and EDX techniques. N-protected aminoalkyl sulfides were characterized by HRMS, 1H, and 13C NMR techniques and were evaluated for their in vitro antifungal activities, against A. Niger using Fluconazole as a standard.
Conclusion
The current study presents an effective approach for synthesizing a new class of sulfides from N-protected aminoalkyl thiols and bromomethyl esters in the presence of nano NiO as a catalyst.
This research investigates antifungal potential of ethanolic extracts from Allium sativum (AS), Alpinia galangal (AG), and the hexane extract of Costus speciosus (CS), with a primary emphasis on preserving their stability through encapsulation. A comprehensive evaluation of three extraction methods was conducted, namely, column extraction, Soxhlet extraction, and maceration for 24 hours. Qualitative tests, such as sodium nitroprusside and lead sulfide tests, were employed to identify sulfur compounds associated with antifungal activity. Quantitative assessments included total polyphenolic content and analyses utilizing X-ray photoelectron spectroscopy (XPS). Encapsulation was applied to extracts demonstrating antifungal activity against Aspergillus niger. The subsequent characterization of encapsulated beads involved assessing particle size, zeta potential, and encapsulation efficiency. The choice of extraction methods was guided by their efficiency, with column extraction selected for AS (4%) due to its capacity to preserve heat-sensitive compounds. Soxhlet extraction (100 ℃, 4 h) was deemed effective for AG (26%) and CS (11%) owing to higher yields. Accurate sulfur detection methods, including the lead sulfide test and XPS analysis, revealed exclusive sulfur compounds in AS. The phenolic content of AS, AG, and CS was quantified at 59.0 ± 0.3, 60.7 ± 0.0, and 65.1 ± 1.0 mg GAE/g, respectively. Notably, only AS (500000 mg/L) exhibited significant antifungal activity against Aspergillus niger, with a mean inhibition zone of 23.7 ± 7.3 mm after 48 hours of incubation at 35℃. To enhance the antifungal efficacy of AS, microencapsulation was employed, and the encapsulated AS beads displayed an average size of 2.38 ± 2.00 μm, a zeta potential of 2.09 ± 0.81 mV, and an encapsulation efficiency of 23%. The presence of phenolics and sulfur compounds in AS suggests promising applications in pharmaceutical and nutraceutical antifungal products.
Non-metal nanoparticles are now a days widely applied in different fields. Among various non-metal nanoparticles (NPs), sulfur nanoparticles (SNPs) are one of the most significant and emerging nanoparticles. In this study, sulfur nanoparticles (SNPs) were prepared by eco-friendly method and well characterized by UV-visible spectroscopy, dynamic light scattering, zeta potential, and transmission electron microscopy. The prepared nanoparticles were spherical in shape with mean size of 35 nm and positive surface charge. Here, an attempt has been made to check the in vitro efficacy of sulfur nanoparticles against the dermatomycosis causing fungus Pichia kudriavzevii . Different antimicrobial experiments were performed to check the potential of SNPs against Pichia kudriavzevii . SEM micrographs and growth inhibition assay confirmed the efficacy of SNPs against the studied fungus. The antifungal activity of SNPs evaluated through the minimum inhibitory concentration (MIC) and the minimum fungicidal concentration (MFC). The values of MIC were 50µM SNPs for the studied species, and MFC was 250µM for Pichia kudriavzevii . Treatment with SNPs was found to be effective in altering the cell morphology, inhibiting normal growth, and reducing the cell membrane content, mainly ergosterol of Pichia kudriavzevii . The status of present study can further be use to unravel the detailed mechanism of antifungal activity of sulfur nanoparticles against Pichia kudriavzevii for future workers.
Cinnamomum camphora leaf essential oil (CEO) was extracted using enzymatic-ultrasound pretreatment followed by microwave assisted extraction (EUP-MAE) method and simultaneously studied as a mycelial growth inhibitor against five important pathogens which cause potato dry rot. The optimum EUP-MAE conditions with a real CEO yield of 19.23 ± 0.12 mg/g were obtained through Plackett–Burman design and Box–Behnken design as follows: 3% of enzyme dosage, 2 h of pretreatment time, 5 of pH, 210 W of ultrasound power, 50 °C pretreatment temperature, 16 mL/g of water to solid ratio, 30 min of microwave time and 500 W of microwave power. Compared to the reference methods, EUP-MAE possessed a highest CEO yield than these of ultrasound-microwave assisted extraction (U-MAE) and traditional hydrodistillation (HD). Gas chromatography-mass spectrometry (GC-MS) analysis demonstrated that eucalyptol, camphor, and α-terpineol were the three main constituents of CEO. Results from in vitro antifungal activity assay revealed that the mycelial growths of all the five tested Fusarium solani, Fusarium culmorum, Fusarium trichothecioides, Fusarium sporotrioides, and Fusarium avenaceum were apparently affected by CEO. These findings not only provide a potential paradigm for the separation of plant essential oil, but also guarantee a promising utilization of the CEO for potato protection to control the Fusarium spp.
Dry rot of potato (Solanum tuberosum L.) is an important postharvest disease during storage. The decay can be caused by several different species of Fusarium spp., such as, F. sambucinum, F. coeruleum, F. oxysporum, F. avenaceum, F. culmorum. The pathogen of Fusarum spp. causing dry rot of potato is considerable different in different countries and regions. The typical symptom of potato dry rot is sunken and wrinkled brown to black tissue patch on tuber with less dry matter and shriveled flesh. Fusarium spp. only invades host through wound or natural orifice during pre-harvest, storage and transportation period. Some Fusarium species infection associated with mycotoxins accumulation, which has phytotoxicity and mycotoxicoses in humans and animals. Synthetic fungicide is the main strategy to control the dry rot of potato, however, there are series of problem, such as environmental pollution, pathogen resistance. An integrated approach to manage the disease includes the introduction of resistant cultivar, appropriate cultural practices, and storage conditions combined with the application of synthetic fungicides pre-harvest or post-harvest. Moreover, some chemical fungicides and microbial antagonists have been integrated into potato dry rot management.
Bipolarithizole A (1), an unprecedented phenylthiazole-sativene sesquiterpenoid hybrid, has been isolated from cultures of the potato endophytic fungus Bipolaris eleusines. The structure with absolute configuration has been established by spectroscopic analysis and quantum chemical computational approaches, as well as by X-ray diffraction analysis. The plausible biosynthetic pathway for 1 has been proposed. Compound 1 shows anti-pathogenic fungi activity against Rhizoctonia solani with an MIC value of 16 μg mL
Biofouling of polyamide membranes is one of the main barriers faced by reverse osmosis (RO) technologies to supply fresh water. Currently, biofouling is addressed by feed water pretreatment using chlorine, followed by membrane cleaning. Chlorine damages polyamide membranes and also generates harmful disinfection byproducts. Thus, safer strategies are needed to prevent biofouling in polyamide membrane systems. This review investigates the applicability of the following non-oxidizing biocides in preventing and controlling biofouling in RO systems, including their antimicrobial efficiency, hazard levels, membrane compatibility, and applicability to drinking water treatment: (1) 2,2-dibromo-3-nitrilopropionamide (DBNPA); (2) 2-methyl-4-isothiazolin-3-one (MIT); (3) sodium bisulfite (SBS), (4) phenoxyethanol (PE), (5) sodium benzoate (SB). According to this review, MIT and DBNPA present most of the features attributed to an ideal anti-biofouling chemical but also are the most hazardous biocides. Due to safety and efficacy, none of the five chemicals were determined to be the final solution to address membrane biofouling. However, alternative RO biocide research is in early development and requires further investigation via biofouling prevention studies. Therefore, future research efforts on the investigation of economic, eco-friendly, and safe antifouling agents to prevent and treat biofouling in RO systems are paramount to promote sustainable water supply in water-stressed countries. HIGHLIGHTS
An evaluation framework for anti-biofouling safety and efficacy is developed.;
DBNPA is a proficient model of biofouling prevention efficacy.;
MIT is a good model for antimicrobial efficacy, although not for safety.;
SBS is a reference for a membrane-compatible antimicrobial.;
PE and SB are good models for safety in biofouling prevention studies.;
Potato dry rot (PDR), caused by Fusarium sulphureum (F. sulphureum) is a serious storage disease and can cause post-harvest rotting and seed piece decay after planting. Physiological and dynamic transcriptome analyses were detected in two PDR-resistant varieties (LS and Atl) to explore the resistant mechanism of potato. The phenylalanine ammonia lyase (PAL) and lignin content rapidly increased after infection at 0.5, 1, 2, 4, 8, 16 days post inoculation (dpi). Meanwhile, the common up-regulated differentially expressed genes (DEGs) were 1025, 1334 and 1394 in LS and Atl at 1, 3, 7 dpi (vs 0 dpi), respectively. STEM (Short Time-series Expression Miner software) and KEGG enrichment analysis revealed that “lignin synthesis-related pathways” and “MAPK signaling pathway-plant” were significantly enriched in the two varieties. The high expressions of PAL, 4CL, CAD and POD genes promoted the synthesis of lignin in the downstream of the pathway, which was filled to the secondary cell wall to increase the resistance to PDR. In addition, FLS2 gene perceived F. sulphureum infection to initiate MAPK cascades signal transduction, and subsequently up-regulated PR1 defensive genes to respond to pathogen attack. These novel findings elucidate the mechanism of dry rot at the transcriptomic level for the first time, and also provide candidate genes for molecular assisted screening and breeding of resistance to PDR.
Fusarium dry rot affects up to 60% of potato tubers during storage. Pathogen resistance development to synthetic chemical fungicides is a main contributing factor. Previous work has demonstrated the use of bacterial antagonists against plant pathogens. In this study, bacteria isolated from disease suppressive composts were tested to evaluate their antagonistic activity against F. sambucinum in vitro, as well as to assess their ability to reduce Fusarium dry rot of potato tubers. To identify the potential implication of antifungal compounds in their inhibitory activity, bacterial extracts were produced and assayed against F. sambucinum mycelial growth and conidial germination. In vitro results showed that all tested bacteria suppressed F. sambucinum mycelial growth over six days of incubation. When testing the bacteria against potato dry rot, 30 of 32 bacteria reduced the symptoms of the disease at the higher bacterial concentration tested. The combined in vitro and in vivo studies indicated Bacillus subtilis B9–8, Pseudomonas moraviensis F9–6, Pseudomonas koreensis F9–9, and Pseudomonas gessardii M9–16 were the most effective strains. Extracts from these four bacteria were able to inhibit mycelial growth and/or conidial germination of the fungal mold. Results from this study suggests that multiple antagonistic bacteria may be useful in controlling Fusarium dry rot on potato tubers. Extracts from the four most effective bacteria indicated that antibiosis was a main mode of action against F. sambucinum.
Small molecules of natural origin have been reported to act as alternatives to synthetic fungicides. These are reviewed in this chapter, and some ideas of new development are given. The list, which is not exhaustive, is the following: acetaldehyde, acetic acid, aldehydes (other than acetaldehyde), aminobutyric acids, ascorbic acid, ethanol, ethylene, jasmonic acid and methyl jasmonate, salicylic acid and methyl salicylate, salts (e.g. sodium bicarbonate, calcium chloride, copper sulphate), sorbic acid and sulphur. There is also discussion about the potential of combinations (e.g. additive or synergistic effects).
Potato (Solanum tuberosum L.), a worldwide, staple food crop, is susceptible to postharvest rots caused by a variety of fungal pathogens, including Fusarium spp., Alternaria spp., Phytophthora infestans, Helminthosporium solani, Rhizoctonia solani, and Colletotrichum coccodes. Rots resulting from infections by these pathogens cause a significant reduction in potato quality and marketable yield. Importantly, some of these decay fungi also produce mycotoxins that represent a potential risk to human health. In the present review, an overview and discussion are provided on the epidemiology and pathogenesis of decay fungi, especially Fusarium spp., that include recent data derived from genomic and phylogenetic analyses. The biosynthesis and functional role of fungitoxic metabolites such as trichothecene mycotoxins and fusaric acid, produced in rotted potatoes are also reviewed. Advances in pre- and postharvest measures for rot management, especially eco-friendly methods including physical control, biological control, the use of natural compounds, and other agricultural management practices are also reviewed. Lastly, novel approaches to control potato dry rot such as the use of mycoviruses and CRISPR technology are highlighted.
Consumer demand warrants improved efficacy and environmental impact of food packaging modalities. Here, multifunctional biodegradable films were prepared using 10, 20, and 40 wt% sodium metabisulfite (SM) as an active compound along with polycaprolactone (PCL). Increased SM content significantly affected film oxygen scavenging, antioxidant, anti-browning, and antimicrobial properties (p < 0.05). The %inhibition of ABTS and DPPH radicals increased from 75.8 % and 7.4% to 99.9% and 25.3 %, respectively, with the SM concentration increasing from 10 to 40 wt%. Additionally, SM/PCL films decreased the browning index from 35.52 to 19.70. SM/PCL films were effective against both Staphylococcus aureus and Escherichia coli and inhibited fungal growth. Our findings further suggest that SM/PCL films significantly reduce the amount of packaged oxygen under the conditions expected in foods (e.g., high humidity and temperature). Thus, SM/PCL films exhibit good potential for the development of active food packaging to prolong food product shelf life.
In recent years, the outbreak of box blight disease caused by Calonectria pseudonaviculata in Caspian Hyrcanian forests of Iran makes it necessary to find both efficient and environmentally friendly compounds as possible alternatives to currently available fungicides. Seven biorational compounds were tested for inhibitory activities against mycelial growth and conidial germination of C. pseudonaviculata Cy‐08 under in‐vitro conditions. Potassium sorbate and salicylic acid as organic compounds and copper (II) sulphate and zinc sulphate as inorganic compounds completely inhibited both mycelial growth and conidial germination of Cy‐08 at 25 mM, comparable with the commercial fungicide, tebuconazole. Ammonium phosphate and boric acid were moderately inhibitory at 25 and 50 mM, also showing fungistatic effects at 100 mM. Ammonium sulphate had the weakest antifungal activity at all tested concentrations. The tested compounds altered the pH of the growing medium (with readings ranging from pH 4.2 to 7.85) but there was no correlation between pH of the amended media and inhibition of fungal growth. C. pseudonaviculata grew in both acidic and alkaline conditions, with mycelial growth decreasing at both lower (4‐5) and higher (11‐12) pH values. The antifungal activity of all tested chemicals was pH‐independent. Therefore, it can be concluded that the more active of these compounds may be used as part of an integrated management program for the control of boxwood blight in forest settings.
Limbah hortikultura berpotensi untuk dijadikan bahan antifungal. Penelitian sebelumnya menunjukkan bahwa ekstrak kulit mangga dengan pelarut etil asetat yang dievaporasi hingga menjadi ekstrak kental secara single mampu menghambat khamir Rhodotorula sp., mencapai 31 mm zona dimana nilai ini lebih besar dari benomyl 500 ppm yang hanya 10 mm. Untuk memperluas spektrum daya hambat, perlu dilakukan formulasi dengan bahan lain. Penelitian ini bertujuan untuk melakukan formulasi ekstrak biji atau kulit mangga dengan pengawet makanan komersial (natrium metabisulfit, kalium sorbat dan natrium benzoat) untuk menghasilkan pengawet yang berspektrum tinggi untuk preservasi buah mangga. Formulasi dilakukan melalui beberapa tahapan untuk menghasilkan konsentrasi dan perbandingan yang tepat. Formula antifungal terbaik berdasarkan uji plate adalah campuran dari ekstrak biji mangga : kalium sorbat 5% (75%:25%) dengan pengenceran 25%. Antifungal ini mampu menghambat kapang dan khamir perusak mangga sebagai berikut: Rhodotorulla sp. sebesar 47,2 mm, Penicillium sp. 41,3 mm, Fusarium sp. 43,6 mm dan Aspergillus niger sebesar 18,2 mm. Aplikasi pada buah mangga melalui penyemprotan menunjukkan hasil 0,2 skor kerusakan dan 2,7% susut bobot lebih baik dibanding kontrol pada penyimpanan hari ke-14 pada suhu 20oC±2oC
Five generally recognised as safe (GRAS) salts with antimicrobial activity were investigated for their potential use as bactericides for the control of lettuce varnish spot [Pseudomonas cichorii (Swingle) Stapp]. The phytotoxicity of salts was first assessed using greenhouse and in vitro assays. Greenhouse assays revealed that salts showed different levels of phytotoxicity. Potassium sorbate, sodium benzoate, and sodium carbonate at higher concentrations caused a noticeable decrease of growth along with foliar phytotoxicity symptoms while sodium metabisulfite and sodium bicarbonate caused exclusively foliar symptoms. Based on the phytotoxic doses 5% determined in vitro, salts can be ranked in ascending order of phytotoxicity as follows: sodium bicarbonate, potassium sorbate, sodium carbonate, sodium benzoate, and sodium metabisulfite. When applied at concentrations causing mild to moderate foliar symptoms of phytotoxicity and no noticeable effect on growth, salts did not significantly affect (p ≤ 0.01) survival of P. cichorii on lettuce leaf tissue and did not significantly reduce (p ≤ 0.01) varnish spot severity. Although sodium metabisulfite was applied at concentrations higher than the minimum inhibitory concentration and minimum bactericidal concentration, it did not affect P. cichorii survival on leaf tissue.
In vitro experiments indicated that boric acid, monopotassium phosphate, sodium metabisulfite and synthetic fungicide fluopyram + tebuconazole were effective in inhibiting conidia germination and germ-tube elongation of Venturia inaequalis. Monopotassium phosphate even at the highest concentration used in the study reduced conidia germination and germ-tube elongation of V. inaequalis by 22.1% and 28.8%, respectively; however, the difference between two compounds at lower concentrations except 0.05% (for conidia germination) and 0.1% (for germ-tube elongation) of boric acid was statistically significant (P ≤ 0.05). Complete inhibition was achieved by 0.01% sodium metabisulfite, 0.035% fluopyram + tebuconazole and 0.2% boric acid. Two orchard trials were conducted on the highly susceptible cv. Mutsu to apple scab to ascertain the efficacy of 0.2% boric acid, 0.5% monopotassium phosphate, 0.5% sodium metabisulfite and 0.035% fluopyram + tebuconazole for the control of apple scab. In both 2013 and 2014, except for the applications of monopotassium phosphate and sodium metabisulfite, the applications of boric acid and fluopyram + tebuconazole to trees at 10-day intervals significantly reduced disease incidence and severity on leaves and fruit compared to the water-treated control. In both years, the efficacy of boric acid and fluopyram + tebuconazole treatments was similar in reducing both disease incidence and severity on leaves and fruit in all monthly assessments from July to September. All treatments were neither phytotoxic to leaves and fruit nor did they adversely affect quality parameters of harvested fruit. These results show that boric acid treatment may be applied as an alternative chemical for the control of apple scab.
Thiabendazole resistant strains of Helminthosporium solani, the silver scurf pathogen, were recovered from 15 of 32 farms surveyed in 1994. Resistance was primarily limited to southern Alberta where 76% of the farms were affected. Only 21% of the farms in the north had a problem. Resistant isolates of Fusarium sambucinum, one of the dry rot pathogens, were found on 12 of 31 farms. In this case, thiabendazole resistance was found on 67% of the farms surveyed in southern Alberta. There was no evidence of resistance in any storage facility in the north. Thiabendazole resistant isolates of both pathogens were invariably cross-resistant to thiophanate-methyl.
The objectives of this study were (1) to evaluate the effect of different salts on the in vitro development of Fusarium solani var. coeruleum, and (2) to evaluate the efficacy of the salts for reducing dry rot severity caused by the pathogen in potato tubers. The study showed that several salts significantly inhibited the mycelial growth of F. solani var. coeruleum. Aluminium acetate, aluminium chloride, sodium benzoate, sodium metabisulfite, potassium sorbate and trisodium phosphate completely inhibited mycelial growth. Exposure of F. solani var. coeruleum conidia to aluminium acetate, potassium sorbate, sodium benzoate, sodium metabisulfite or trisodium phosphate at 0.2 M resulted in 100% mortality of the conidia after 1 h while aluminium chloride and aluminium lactate caused 100% mortality after an exposure of 24 h. In order to evaluate the effect of salts on potato dry rot development, F. solani var. coeruleum-inoculated tubers were treated with the different salts and disease severity was evaluated following an incubation period of 7 d. Among the test salts, only aluminium chloride caused a significant reduction in potato dry rot compared with the control. The study points out the possibility of using aluminium chloride to control potato dry rot.
Potato dry rot, caused by Fusarium sambucinum, is a major postharvest disease of economic significance worldwide. Postharvest application of thiabendazole to control dry rot is becoming less effective since many strains of F. sambucinum have become resistant to this fungicide. Thus, alternative control strategies are needed. In vitro studies showed that several salts (0.2 M) inhibited completely mycelial growth and spore germination of F. sambucinum. Among these salts, sodium benzoate, sodium metabisulfite, potassium sorbate, trisodium phosphate and aluminium salts were fungitoxic. In vivo studies showed that aluminium chloride in curative application and sodium metabisulfite, sodium carbonate and sodium bicarbonate in preventive application significantly reduced the development of dry rot in potato tuber. Results from this study demonstrate that selected salts can be used to control potato dry rot.
Losses from postharvest fruit diseases range from 1 to 20 percent in the United States, depending on the commodity. The application of fungicides to fruits after harvest to reduce decay has been increasingly curtailed by the development of pathogen resistance to many key fungicides, the lack of replacement fungicides, negative public perception regarding the safety of pesticides and consequent restrictions on fungicide use. Biological control of postharvest diseases (BCPD) has emerged as an effective alternative. Because wound-invading necrotrophic pathogens are vulnerable to biocontrol, antagonists can be applied directly to the targeted area (fruit wounds), and a single application using existing delivery systems (drenches, line sprayers, on-line dips) can significantly reduce fruit decays. The pioneering biocontrol products BioSave and Aspire were registered by EPA in 1995 for control of postharvest rots of pome and citrus fruit, respectively, and are commercially available. The limitations of these biocontrol products can be addressed by enhancing biocontrol through manipulation of the environment, using mixtures of beneficial organisms, physiological and genetic enhancement of the biocontrol mechanisms, manipulation of formulations, and integration of biocontrol with other alternative methods that alone do not provide adequate protection but in combination with biocontrol provide additive or synergistic effects.
Aluminum and bisulfite salts inhibit the growth of several fungi and bacteria, and their application effectively controls potato soft rot caused by Erwinia carotovora. In an effort to understand their inhibitory action, ultrastructural changes in Erwinia carotovora subsp. atroseptica after exposure (0 to 20 min) to different concentrations (0.05, 0.1, and 0.2 M) of these salts were examined by using transmission electron microscopy. Plasma membrane integrity was evaluated by using the SYTOX Green fluorochrome that penetrates only cells with altered membranes. Bacteria exposed to all aluminum chloride concentrations, especially 0.2 M, exhibited loosening of the cell walls, cell wall rupture, cytoplasmic aggregation, and an absence of extracellular vesicles. Sodium metabisulfite caused mainly a retraction of plasma membrane and cellular voids which were more pronounced with increasing concentration. Bacterial mortality was closely associated with SYTOX stain absorption when bacteria were exposed to either a high concentration (0.2 M) of aluminum chloride or prolonged exposure (20 min) to 0.05 M aluminum chloride or to a pH of 2.5. Bacteria exposed to lower concentrations of aluminum chloride (0.05 and 0.1 M) for 10 min or less, or to metabisulfite at all concentrations, did not exhibit significant stain absorption, suggesting that no membrane damage occurred or it was too weak to allow the penetration of the stain into the cell. While mortality caused by aluminum chloride involves membrane damage and subsequent cytoplasmic aggregation, sulfite exerts its effect intracellularly; it is transported across the membrane by free diffusion of molecular SO2 with little damage to the cellular membrane.
Aluminum chloride and sodium metabisulfite have shown high efficacy at low doses in controlling postharvest pathogens on potato
tubers. Direct effects of these two salts included the loss of cell membrane integrity in exposed pathogens. In this work,
four fungal potato pathogens were studied in order to elucidate the role of membrane lipids and lipid peroxidation in the
relative sensitivity of microorganisms exposed to these salts. Inhibition of mycelial growth in these fungi varied considerably
and revealed sensitivity groups within the tested fungi. Analysis of fatty acids in these fungi demonstrated that sensitivity
was related to high intrinsic fatty acid unsaturation. When exposed to the antifungal salts, sensitive fungi demonstrated
a loss of fatty acid unsaturation, which was accompanied by an elevation in malondialdehyde content (a biochemical marker
of lipid peroxidation). Our data suggest that aluminum chloride and sodium metabisulfite could induce lipid peroxidation in
sensitive fungi, which may promote the ensuing loss of integrity in the plasma membrane. This direct effect on fungal membranes
may contribute, at least in part, to the observed antimicrobial effects of these two salts.
The yeast, Pichia guilliermondii, was evaluated for its activity in reducing post-harvest decay of tomato fruit caused by Alternaria solani, Rhizopus stolonifer, and Botrytis cinerea. The potential of using P. guilliermondii to control natural infections, and its effects on the post-harvest quality of tomato fruit were investigated. The results showed that a washed-cell suspension of the antagonistic yeast was effective at inhibiting all three pathogens, and tomato fruit treated with the antagonist at 10 7 CFU ml-1 or 108 CFU ml-1 had significantly lower incidences of disease and smaller lesion diameters. The concentration of antagonistic yeast had a significant effect. Higher concentrations of the antagonist gave a lower incidence of disease. Results for reducing the development of natural decay on intact fruit were similar to those for artificially-inoculated fruit, and the effectiveness of the antagonistic yeast as a biocontrol agent was significant for tomato fruit at three different stages of maturity. Compared to controls, the incidence of natural decay on antagonist-treated fruit decreased significantly, and none of the treatments impaired the quality parameters (e.g., weight loss, total soluble solids content, titratable acidity, ascorbic acid content and fruit colour). Thus, we conclude that the yeast, P. guilliermondii, can control several post-harvest diseases of tomato fruit and not affect tomato fruit quality.
During the 1992-1993 and 1994-1995 winter storage period for potatoes (Solanum tuberosum) in Quebec, New Brunswick, and Prince Edward Island, tubers were collected which had symptoms of fusarium tuber rot and silver scurf and which had been treated commercially after harvest with thiabendazole. Resistance to thiabendazole was detected in isolates of Fusarium sambucinum and Helminthosporium solani but not in isolates of F. avenaceum and F. oxysporum. However, the majority of those farms surveyed (64%) had adequate disease control with no pathogen isolated from the diseased tubers. Incidence and EC50 values of resistant isolates were lower than found elsewhere and the occurrence of farms with resistant isolates of F. sambucinum (18%) was greater than for H. solani (7%). For H. solani, EC50 values of resistant isolates were substantially less than those found in Alberta. While the study investigated commercial operations employing a wide range of thiabendazole rates (6-42 g a.i. t1), no specific trends were detected between the occurrence of resistant isolates and cultivar or thiabendazole application rate.
Rhizopusstolonifer causes severe losses to Israeli grape exports. The fungus develops on mature berries in the field, during storage at temperatures above 08C and during shelf-life. It was isolated from naturally contaminated soils throughout the year, and from fruits after mid-June. The airborne spore population increased in vineyards at the time of fruit maturation and was related to the proximity of stone-fruit orchards. The size of this population was highly correlated with disease incidence and thus may be a satisfactory tool for disease prediction. Intact young berries were more resistant than mature ones to Rhizopus inoculation, in both the vineyard and in the laboratory. Mechanical wounding, or chloroform dips, dramatically increased the susceptibility of young berries. The decline in acidity and the increase in the soluble solids content during growth and maturation of the berry were accompanied by an increase in susceptibility to inoculation. Scanning electron microscopy showed the fruit surface to be covered with white amorphous structures. At higher magnifications small cracks (approximately 1 μm in length) were observed on the surface but in no case was fungal penetration noticed through these cracks. In artificially inoculated fruits the fungus germinated near the wound and developed vigorously inside and around the fissure, producing sporangia. The young sporangium is covered by a smooth external layer which is compressed against the sporangiospores. After lysis of the cover, the young hexagonal sporangiospores can be observed. With maturation, the columella collapses and the mature sporangiospores are dispersed. In naturally infected berries, an important path for fungal penetration is the incomplete connection between the berry and the pedicle. Heavily infested berries become disconnected from their pedicles. Two chemicals applied to the surrounding atmosphere, orthophenyl phenate (as a fog) and calcium hypochlorite (as chlorine vapour), significantly decreased postharvest decay in artificially inoculated berries.
Potato silver scurf, caused by Helminthosporium solani, is an important postharvest disease of economic significance. Control of H. solani has been accomplished primarily by postharvest applications of thiabendazole. However, many strains of H. solani have become resistant to thiabendazole, resulting in failure of disease control. Consequently, alternative control strategies are needed, This study showed that several salts significantly reduced silver scurf development on potato tuber at a concentration of 0.2 M and that the timing of application also influenced salt efficacy. Among the 23 tested salts, aluminum chloride was the only one reducing silver scurf severity when applied either 2, 4, or 7 days after H. solani inoculation. Aluminum lactate, potassium sorbate, sodium carbonate, sodium metabisulfite, and trisodium phosphate also markedly reduced silver scurf severity but only when applied 2 or 4 days after inoculation. Ammonium acetate, calcium chloride, sodium benzoate, sodium citrate, and sodium formate reduced disease severity by at least 50% when applied 2 days after H. solani inoculation. With the exception of calcium chloride and sodium formate, these salts also were shown to strongly inhibit H. solani mycelial growth or spore germination in vitro. Results of this study further demonstrate the possibility of using selected salts for the control of potato silver scurf.
Fungicide resistance in Botrytis cinerea has caused increased concerns about losses due to gray mold on many important agricultural and horticultural crops. Since bicarbonates have been reported to be an effective control of powdery mildew on greenhouse roses, the purpose of this research was to determine the effectiveness of bicarbonates against B. cinerea. Assessments were made of in vitro fungal colony growth in response to ammonium, potassium, and sodium bicarbonates. Bicarbonates inhibited colony growth at concentrations as low as 20 mM. In addition, comparisons of several ammonium, potassium, and sodium salts were conducted to determine whether cation or anion is the active moiety. Although the bicarbonate anion primarily affected growth, the ammonium cation also contributed greatly to fungal growth inhibition. With the exception of dibasic phosphate, only salts with high pK(a), values or that are reducing agents, or both, decreased colony growth. The effect of pH on B. cinerea was then examined. Since bicarbonate anion concentration is related to pH, this parameter was examined in combination with several salts to separate pH effects from bicarbonate effects. As pH increased from 7.0 to 8.5, colony growth decreased with bicarbonates and phosphates, but not with ammonium sulfate. Since bicarbonates and phosphates decreased colony growth more than could be accounted for from pH alone, and since both have buffering characteristics, buffering capacity was examined and found to decrease colony growth but not as much as bicarbonate. Therefore, bicarbonates control B. cinerea colony growth in vitro, and both pH and buffering capacity contribute to, but are not solely responsible for, growth inhibition.
Seven organic and inorganic salts were tested for suppression of silver scurf, a postharvest disease of potato tubers caused by Helminthosporium solani. Potassium sorbate, calcium propionate, sodium carbonate, sodium bicarbonate, potassium carbonate, potassium bicarbonate, and ammonium bicarbonate were added to V8 agar at concentrations of 0.06-0.2 M. Radial growth of H. solani was significantly reduced (P < 0.05) by all salts at all concentrations. All salts except sodium bicarbonate and potassium bicarbonate were fungicidal at 0.2 M. Effects of postharvest salt treatments on disease severity and sporulation of H. solani on inoculated and naturally infected potato tubers were evaluated in separate experiments. Greenhouse-grown tubers were inoculated with H. solani spore suspensions (2 x 105 spores/ml), incubated for 5 days, dipped into 0.2 M solutions of each of the salts, and incubated in a moist chamber at 22-24°C for 6 weeks. All salt treatments prevented lesion development and sporulation of H. solani and differed significantly (P < 0.05) from the control. Postharvest applications of test compounds (0.2M) also significantly (P < 0.05) reduced disease severity and H. solani sporulation on naturally infected, field-grown tubers after 15 weeks of storage at 10°C. Salt treatments did not differ in disease or pathogen suppression. These relatively nontoxic organic and inorganic salts have potential as postharvest applications for control of silver scurf.
Reduction of germination of alternaria spores after exposure to sulfur dioxide (SO/sub 2/) was quantitatively proportional to the SO/sub 2/ concentration and to the exposure time. Wet spores were more sensitive than dry spores to SO/sub 2/. The sensitivity of dry spores to SO/sub 2/ increased rapidly when they were placed in a water-saturated atmosphere. Spores incubated at lower relative humidities were more resistant to SO/sub 2/ than wet spores or those hydrated in a saturated atmosphere for 4 hr.
In the search for alternatives to the use of synthetic fungicides, aqueous spice extracts were evaluated for their effects on the mycelial growth of various spoilage pathogens and their ability to control potato dry rot and carrot cavity spot in vivo. Results showed that cinnamon, ginger and nutmeg significantly inhibited the mycelial growth of Aspergillus niger (Ascomycota), Fusarium sambucinum (Ascomycota), Pythium sulcatum (Oomycota) or Rhizopus stolonifer (Zygomycota), whereas horseradish extract did not lead to the inhibition of any microorganism at the tested concentration. Among the most effective extracts, 0.05 g mL-1 of cinnamon extract completely inhibited A. niger and P. sulcatum, and 0.10 g mL-1 of cinnamon extract completely inhibited F. sambucinum. A concentration of 0.05 g mL -1 of ginger extract also caused 100% inhibition of P. sulcatum. In vivo, cinnamon extract significantly reduced lesions of potato dry rot and carrot cavity spot, and ginger extract reduced lesions of carrot cavity spot. These results indicate that aqueous cinnamon and ginger extracts could provide an alternative to the use of synthetic fungicides to control these pathogens.
The fungal membrane has the fundamental role of maintaining cell order and integrity. Therefore, a number of disease-control methods have involved compounds that directly or indirectly target fungal membranes or their components. Some of these antifungal compounds affect the synthesis of specific membrane components (e.g., sterol biosynthesis inhibitors) and are among the most effective antifungals in plant disease control. However, these compounds are prone to pathogen resistance development that greatly shortens their effective life span. Conversely, some antifungals possess generalized effects on fungal membrane integrity. These compounds are typically not as effective, but they are less likely to induce resistance in sensitive fungi. The use of both classes of antifungals is still of great relevance in plant pathology, in particular in the case of integrated pest management. The correct use of antifungals that target fungal membranes could be the basis of a promising strategy to lower applications of synthetic pesticides while lengthening the effective life span of the disease control measure.
One hundred and twenty isolates of Pythium species were recovered from cavity spot lesions on carrots grown in the Fraser Valley of British Columbia during 1989 to 1992. Pathogenicity tests performed in vitro on carrot seedlings, on mature carrol roots, or on carrots planted in soil, showed that 83 isolates belonging to eight species were pathogenic and were capable of causing cavity spot symptoms. These included Pythium violae, P. sulcatum, P. ultimum var. ultimuin, P. irregulare, P. sylvaticum, P. acanthicum, P. paroecandrum, and P. mamillatum. The first five species have been reported to cause cavity spot in other carrotgrowing regions of the world, while the latter three represent new records. In greenhouse tests to determine the effects of soil moisture, temperature, and carrot age on development of cavity spot, high soil moisture (near field capacity) or flooding, and a temperature of 15°C were found to be optimal. Carrot age (1 to 3 months) did not influence cavity spot development. Thirty-eight isolates, representing all Pythium species recovered, were compared for pectolytic enzyme activity in a cup-plate assay and for virulence on mature carrot roots in vitro. The highly virulent isolates were found to produce significantly higher (P 0.03) enzyme levels (up to 11.6 units per mg dry weight of mycelium) compared with the moderately or weakly virulent isolates. The most virulent isolates were P. violae, P. sulcatum, and one isolate of P. ultimuin var. ultiiimm, A histopathological study of P. violae on carrot revealed the disintegration of host cells and development of hyphae beneath the epidermis, ultimately resulting in the collapse of the lesioned area to form a cavity. Using an in vitro mature carrot root inoculation procedure, 37 carrot cultivars were evaluated over a 2-year period for resistance or susceptibility to cavity spot. The most resistant cultivars included Panther, Caropride, Fannia, and Navajo.
Gray mold and rhizopus rot, caused by Botrytis cinerea and Rhizopus stolonifer, respectively, are major diseases of strawberry (Fragaria ×ananassa) fruits, causing significant economic losses during storage. In this study, the effect of chlorine atmospheres on spore viability and mycelial growth of B. cinerea and R. stolonifer and on the development of gray mold and rhizopus rot on stored strawberries was evaluated. The results showed that spore mortality in R. stolonifer and B. cinerea was complete following a 6 h exposure to a chlorine atmosphere of 10 mg per litre of moist air, while mycelial growth of R. stolonifer and B. cinerea was completely inhibited at concentrations of 5 and 20 mg/L, respectively. At concentrations as low as 10 mg/L, chlorine provided a marked reduction in incidence of rhizopus rot and gray mold on strawberries after a 9 h exposure period. For both diseases, a chlorine atmosphere of 20 mg/L reduced the incidence by a minimum of 60% without affecting strawberry color or firmness. The results of this study suggest that exposure of strawberries to chlorine atmospheres represents a potential method for controlling postharvest gray mold and rhizopus rot.
Each year, potato late blight [Phytophthora infestans] and pink rot [Phytophthora erythroseptica] are responsible for significant postharvest economic losses. Because of restrictions on the use of synthetic fungicides on food, there is currently a need for less toxic, disease-controlling compounds for postharvest application. To address this need, the preventative and curative effects, as well as seed piece phytotoxicity, of various salt compounds were tested using live tubers of the potato 'Superior'. Compounds were tested as dips at the concentrations 0.002, 0.02, 0.2 mol/L and compared with a distilled water dip as a control. Tubers were inoculated with sporangia of P. infestans or active zoospores of P. erythroseptica either before or after treatment with the various compounds. When concentration data were pooled and grouped means were tested for significant differences (P < 0.05), potassium sorbate, sodium metabisulfite, alum, sodium hypochlorite, copper sulfate pentahydrate, acetic acid, and Penncozeb® 75DF applied curatively provided disease inhibition that was significantly greater than that of the control for both late blight and pink rot. When applied as a preventative treatment, all compounds were significantly different (P < 0.05) from the untreated control in the inhibition of pink rot; however, only sodium metabisulfite, sodium hypochlorite, copper sulfate pentahydrate, and Penncozeb 75DF significantly reduced the severity of late blight. Phytotoxicity was observed when sodium hypochlorite, sodium metabisulfite, acetic acid, and copper sulfate pentahydrate were applied as seed piece treatments, at a concentration of 0.2 mol/L. Our studies suggest there is a potential for the use of selected salt compounds for control of postharvest diseases of potato.
Among 15 antimycotic agents tested, maximum activity was displayed by 5,7-dichloro-8-oxyquinoline, both as regards the microorganism spectrum and the minimum inhibitory concentration. The antimycotic effect of 2-aminotridecane-undecylenate and 2-aminotridecane-2-chloro-4-nitrophenolate was greater than that of 2-aminotridecane, undecylenic acid and 2-chloro-4-nitrophenol alone. Biochemical resistance develops relatively rapidly in aTrichophyton mentagrophytes strain on contact with fungicidin, 2-chloro-4-nitrophenol and 5,7-dichloro-8-oxyquinoline. ATrichophyton mentagrophytes strain resistant to one of these three agents is also several times less sensitive to all the other test substances except septonex.
Losses of fruits and vegetables worth many millions of dollars occur each year from the time the produce is harvested until it reaches the home of consumers. In New York City, for example, approximately 700 carloads of fruits and 2300 carloads of vegetables are lost annually by decay (165). Some of these losses can be reduced by treatments now available, and studies are constantly in progress to develop new methods to reduce decay losses. Information presented here summarizes treatments formerly used to reduce decay, those used now, and those that show possibilities for future use. 175 references.
Postharvest deterioration of table grapes generally results from berry decay and/or desiccation of stems and pedicels. Conventional methods to avoid these problems include SO2 fumigation or release from generator pads containing a metabisulfite salt, and packaging of the fruit in polyethylene liners. SO2 is usually effective in preventing decay as long as its level is sufficiently high. However, high levels can result in fruit damage, unpleasant aftertaste, and allergies. Our objective was to examine the effect of applying a postharvest ethanol dip on the decay of table grapes. Immersion of detached berries in 70% ethanol eliminated most of the fungal and bacterial populations on the berry surface, but had little effect on survival of yeasts. In vitro development of spores of the major postharvest pathogen of table grapes, Botrytis cinerea was arrested by 40% ethanol. Dipping of grape bunches in 50, 40 or 33%, but not in 20% ethanol, prior to packaging, resulted in inhibition of berry decay that was equivalent to, or better than that achieved with SO2, released from generator pads. Decay control was generally feasible for a cold storage period of 4–5 weeks and sometimes more. Ethanol did not impair bunch appearance, berry bloom or berry firmness and ethanol-treated berries obtained higher organoleptic scores than SO2-treated berries.
Post-harvest potato diseases are responsible for significant economic loss. Tuber infection may occur naturally through lenticels and eyes or mechanically through wounds incurred during harvest. There are few fungicides approved for use on human foodstuffs and there is a necessity to evaluate and screen the efficacy of alternative compounds against pathogens responsible for post-harvest disease in potatoes. In vitro trials were conducted to evaluate the effect of several organic and inorganic salt compounds and two commercial fungicides on mycelial growth, sporulation and spore germination of Alternaria alternata, Botrytis cinerea, Fusarium solani var. coeruleum, Phytophthora erythroseptica, P. infestans, Verticillium albo-atrum, and V. dahliae. The effects of various salt compounds on these fungi were evaluated at three concentrations: 0.002, 0.02 and 0.2 M. Overall, mycelium growth and spore germination of all pathogens were strongly inhibited by sodium metabisulfite and propyl-paraben. Spore ge
Several salt compounds were tested in vitro as inhibitors of Erwinia carotovora subsp. atroseptica (van Hall) Dye (Eca) and Erwinia carotovora subsp. carotovora (Jones) Bergey, Harrison, Breed, Hammer & Huntoon (Ecc), causal agents of bacterial soft rot of potato. All compounds were mixed with potato dextrose agar (PDA) to the concentrations 0.002 M, 0.02 M and 0.2 M PDA amended with sodium metabisulfite, propyl-paraben, alum, potassium sorbate, calcium propionate and copper sulfate pentahydrate were completely inhibitory at the lowest concentration (0.002 M). Studies examining the preventative and curative effects of the most effective compounds were conducted using Ecc (strain 71). As preventative disease control measures, tubers treated only with aluminum acetate, alum, calcium propionate, sodium bicarbonate, sodium hypochlorite or copper sulfate pentahydrate resulted in significantly (P < 0.001) less soft rot than the untreated control. As curative disease contr
Aluminum chloride (AlCl(3)) and sodium metabisulfite (Na(2)S(2)O(5)) have received increasing attention as antifungal agents for the control of plant diseases. In an effort to understand their toxic action on fungi, ultrastructural changes and membrane damage in Fusarium sambucinum (Ascomycota) and Heterobasidion annosum (Basidiomycota) in response to salt exposure was investigated using transmission electron microscopy. Conidial membrane damage was quantified using SYTOX Green stain, which only enters altered membranes. The results showed that mortality of the conidia was generally closely associated with SYTOX stain absorption in F. sambucinum treated with Na(2)S(2)O(5) and in H. annosum treated with AlCl(3) or Na(2)S(2)O(5), suggesting that these salts cause membrane alterations. For both fungi, ultrastructural alterations in conidia treated with AlCl(3) and Na(2)S(2)O(5) included membrane retraction, undulation, and invagination. At higher concentrations or exposure periods to the salts, loss of membrane integrity, cytoplasmic leakage, and cell rupture were observed. Ultrastructural alterations and increased SYTOX stain absorption in salt-treated conidia appear consistent with a mode of action where AlCl(3) and Na(2)S(2)O(5) alter membrane integrity and permeability.
In this study we examined the mechanism by which ammonium bicarbonate inhibits mycotoxigenic fungi. Elevated extracellular pH, alone, was not responsible for the antifungal activity. Although conidia of Penicillium griseofulvum and Fusarium graminearum had internal pH (pHi) values as high as 8.0 in buffer at an external pH (pHo) of 9.5, their viability was not markedly affected. The pHi values from conidia equilibrated in glycine-NaOH-buffered treatments without ammonium bicarbonate or ammonium sulfate were similar to values obtained from buffered treatments containing the ammonium salts. Thus, inhibition did not appear to be directly related to increased pHi. Ammonium sulfate in buffered media at pH greater than or equal to 8.7 was as inhibitory as ammonium bicarbonate, but was completely ineffective at pH less than or equal to 7.8. The hypothesis that free ammonia caused the fungal inhibition was tested by using ammonium sulfate as a model for ammonium bicarbonate. Viability, expressed as log CFU/ml, and percent germination of P. griseofulvum and F. graminearum decreased dramatically as the free ammonia concentration increased. Germination rate ratios (the germination rate in buffered ammonium sulfate divided by the germination rate in buffer alone) decreased linearly as the free ammonia concentration increased, further establishing NH3 as the toxic agent. Ammonium bicarbonate inhibits fungi because the bicarbonate anion supplies the alkalinity necessary to establish an antifungal concentration of free ammonia.
This study was designed to determine whether lettuce treated with a commercially available sulfite-containing freshener prepared according to manufacturer's directions could provoke reactions in sulfite-sensitive subjects with asthma (SSAs). Five adult SSAs with stable asthma who had multiple prior reactions to double-blind, placebo-controlled, sulfite-capsule challenges were studied. Each patient ingested, in a double-blind, placebo-controlled fashion, four portions of lettuce (3 oz) pretreated with one of two commercially available, nearly identical vegetable fresheners. One freshener contained sodium bisulfite and was used on one portion of lettuce. The other freshener contained no sulfite and was used on three portions of lettuce. The fresheners were prepared and the lettuce was treated according to label instructions. After baseline spirometry, the SSAs consumed the lettuce samples with the same dressing of their choice, serial spirometry was performed, and a positive reaction was defined as a greater than 20% drop in FEV1 decreased 0% to 7%; mean, 3%. Two of the subjects experienced severe reactions to the sulfite-treated lettuce. One of these reactions was life threatening; the other reaction occurred despite placing only 30% of the usual sulfite dose on the lettuce. This study has demonstrated that sulfite-treated lettuce is capable of provoking bronchospasm in SSAs and suggests that such food is one cause of restaurant-provoked asthma in these individuals.
In the last 2 years, 2,894 consecutive eczematous patients were patch tested with sodium metabisulfite 1% pet. Positive reactions were elicited in 50 subjects (1.7%). All 50 patients were also positive to potassium metabisulfite 1% pet. and sodium bisulfite 1% and 5% pet., while only 2 of them were positive to sodium sulfite 1% pet. Prick tests and intradermal tests with a sodium metabisulfite solution (10 mg/ml) were negative. No flare-ups of dermatitis or patch test were provoked by oral challenge with 30 mg and 50 mg of sodium metabisulfite. The dermatitis was taken to be occupational in 7 cases. In only 5 out of 43 non-occupational cases was the positive reaction considered relevant.
The use of polymethylmetacrylate beads for local delivery of antibiotics requires a second surgical procedure for their removal and resorbable calcium sulphate exhibits cytotoxic effects. In this work, a bioresorbable composite of calcium sulphate and nanoparticulate hydroxyapatite (PerOssal was studied regarding its antibiotic release properties and biocompatibility. Material characteristics of plain PerOssal and pure calcium sulphate pellets were studied using scanning and electron microscopy and X-ray methods. Pellets were soaked with gentamicin and vancomycin, respectively. Release properties of both antibiotics from both materials were investigated over 10 days. Quantitative and qualitative cytotoxic assays were performed for biocompatibility testing. Specific surface was 106 m(2)/g for PerOssal and 2.2 m(2)/g for pure calcium sulphate. Almost complete elution of gentamicin was found for both carrier materials (94.7% for PerOssal vs. 95.8% for calcium sulphate) within 10 days, whereas vancomycin release was higher for PerOssal (96.3% vs. 74.8%). PerOssal showed higher initial and lower release after approximately 5 days compared to calcium sulphate. No significant in vitro cytotoxic differences were found between PerOssal and nontoxic cell culture medium. Calcium sulphate showed cytotoxic effects in two out of four tests. PerOssal exhibits excellent properties regarding resorption, biocompatibility, and antibiotic release.
Cavity spot is one of the most common and serious diseases of carrot (Daucus carota L). The disease, caused by different species of Pythium, including P. violae Chesters & Hickman, P. sulcatum Pratt & Mitchell and P. sylvaticum Campbell & Hendrix, leads to frequent high rejection rates during grading worldwide. In the area of the city of Québec, the disease is caused mainly by P. sulcatum, P. sylvaticum and P. macrosporum Vaartaja & van der Plaats-Niterink. Cavity spot can be controlled with metalaxyl, but reports are emerging that this treatment show little or no efficacy in many regions. This situation reinforces the need for alternative fungicides. The objectives of the present study were: (1) to determine the sensitivity of 14 pathogenic isolates of P. sulcatum, P. sylvaticum and P. macrosporum collected from carrots produced in the area of the city of Québec to different broad-spectrum and oomycete-specific fungicides (chlorothalonil, etridiazole, fludioxonil, fosetyl-Al, metalaxyl, zoxamide), (2) to evaluate the efficacy of the fungicides in controlling cavity spot, and (3) to evaluate the risk of resistance development of isolates with the best-performing fungicide(s). The determination of EC50 for the fungicides tested showed that most isolates were highly sensitive to both metalaxyl and zoxamide but insensitive to fludioxonil, fosetyl-Al and chlorothalonil. In greenhouse assays, only zoxamide provided significant and consistent disease control as measured by the number of cavity spot lesions caused by P. sulcatum. Investigations into the risk of resistance development to zoxamide showed that, for specific isolates, repeated exposure to the fungicide resulted in a loss of sensitivity.
Diseases and Pests of Vegetable Crops in Canada
- R J Howard
- J A Garland
- W L Seaman
Howard, R.J., Garland, J.A., Seaman, W.L., 1994. Diseases and Pests of Vegetable Crops in Canada. The Canadian Phytopathological Society and the Entomological Society of Canada, Ottawa, Canada.
The efficacy of preharvest salts treatment on incidence of snap bean pod rots during storage
- H H M Soltan
- T J Abd-Elrahman
- A M A Naffa
Soltan, H.H.M., Abd-Elrahman, T.J., Naffa, A.M.A., 2006. The efficacy of preharvest salts treatment on incidence of snap bean pod rots during storage. Egypt. J. Phytopathol. 34, 31–40.
Food Preservatives United Kingdom. SAS Institute Inc., 1999. SAS/STAT User's Guide. Version 8 Chemical treatment to reduce postharvest spoilage of fruits and vegetables
- N J Russell
- G W Gould
Russell, N.J., Gould, G.W., 1991. Food Preservatives. Blackie and Son, London, United Kingdom. SAS Institute Inc., 1999. SAS/STAT User's Guide. Version 8. SAS Institute Inc., Cary, NC. Smith, W.L., 1962. Chemical treatment to reduce postharvest spoilage of fruits and vegetables. Bot. Rev. 28, 411–445.
Handbook of Food Additives Food Additive Dictionary
- T E Furia
Furia, T.E., 1972. Handbook of Food Additives. CRC Press, Cleveland, OH. Health Canada, 2006. Food Additive Dictionary. Health Canada, Ottawa, Canada.