Métodos para la desinfección de frutas y hortalizas
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... Peroxyacetic acid (PAA), a combination of H 2 O 2 and AA (Abdelrhim et al., 2022;Tantawy et al., 2020), has long been used as an antimicrobial food additive due to its safety and inexpensive and increasingly in the food industry with several commercial formulations (Beuchat et al., 2004). PAA treatment has been reported to control postharvest decay caused by Listeria monocytogenes on iceberg lettuce (Mari et al., 2004), Monilinia laxa and Rhizopus stolonifer on stone fruits (Garmendia and Vero, 2006), Penicillium expansum on orange (Abd-El- Kader et al., 2011) and Botrytis cinerea on strawberry (Michiu et al., 2022). Abd-Alla et al. (2006) also claimed that PAA is efficient in reducing black mold disease severity on onion bulbs during storage and it can be commercially used as a new approach to control disease infection in onion bulbs during transportation and storage. ...
During field conditions and storage, onion bulbs are often severely affected by Aspergillus niger L., which leads to substantial yield and quality loss due to black mold. In the El-Minia region of Egypt, we isolated several strains of A. niger from different onion bulbs. To combat the black mold rot disease caused by A. niger, we tested the individual and combined effects of acetic acid and hydrogen peroxide against the most virulent strain under both in vitro and storage (180 days) conditions. Additionally, we measured the levels of antioxidant compounds such as phenolic acids, polyphenols, and ascorbic acid. Our pathogenicity tests helped us identify the most virulent isolate. We found that the environmentally friendly compound peroxyacetic acid, derived from the combination of hydrogen peroxide and acetic acid, reduced black mold infection in both, in vitro and storage conditions. Treating postharvest onion bulbs with 0.2 g L −1 acetic acid and 0.4 g L −1 hydrogen peroxide promised to mitigate the development of black mold rot for 180 days of storage. Furthermore, our results indicated that these treatments increased bioactive antioxidant compounds such as ascorbic acid, phenolic compounds, and polyphenols. These compounds, as secondary metabolites, served as the first line of defense against onion rot disease during storage. In conclusion, applying peroxyacetic acid proved a practical approach to controlling black mold rot disease development in onion bulbs during storage.
... Peroxyacetic acid (PAA), a combination of H 2 O 2 and AA (Abdelrhim et al., 2022;Tantawy et al., 2020), has long been used as an antimicrobial food additive due to its safety and inexpensive and increasingly in the food industry with several commercial formulations (Beuchat et al., 2004). PAA treatment has been reported to control postharvest decay caused by Listeria monocytogenes on iceberg lettuce (Mari et al., 2004), Monilinia laxa and Rhizopus stolonifer on stone fruits (Garmendia and Vero, 2006), Penicillium expansum on orange (Abd-El- Kader et al., 2011) and Botrytis cinerea on strawberry (Michiu et al., 2022). Abd-Alla et al. (2006) also claimed that PAA is efficient in reducing black mold disease severity on onion bulbs during storage and it can be commercially used as a new approach to control disease infection in onion bulbs during transportation and storage. ...
... Cherry tomato fruits (Solanum lycopersicum var. cerasiforme) were washed for 15 min in water with Tween 80 and bleach at 0.05% and 0.15%, respectively [18]. Finally, the tomatoes were rinsed thrice (10 min each) in distilled water. ...
Plant pathogenic fungi are the most important cause of losses in agriculture. In the context of the overuse of synthetic fungicides, natural products are an encouraging alternative to control these plant pathogenic fungi. In this study, we tested the antifungal capacity of four strains of the genus Streptomyces against the plant pathogenic fungi Alternaria alternata, Botrytis cinerea and Fusarium oxysporum. We also investigated the effect of applying the extracts with the highest antifungal activities in a post-harvest setting for the control of B. cinerea on cherry tomato fruits. The results revealed the ability of these strains, especially Streptomyces netropsis A52M, to inhibit in vitro the growth and, in some cases, the sporulation of plant pathogenic fungi. The protective effect of the S. netropsis A52M extracts on post-harvest cherry tomato fruits infected with B. cinerea was demonstrated. In addition, when grown in co-culture, we observed an interesting phenomenon in which the Streptomyces mycelium physically encapsulated the fungal mycelium, contributing to its inhibition. This outcome offers the potential for research into the role of physical microbial interactions in fungal biocontrol. To sum up, the findings outlined here for the interactions between Streptomyces strains and plant pathogenic fungi are a promising, safer, and more sustainable biocontrol alternative to chemicals for agriculture. This is of particular interest in the protection of perishable agricultural products during the post-harvest phase.
... Cherry tomato fruits (Solanum lycopersicum var. cerasiforme) were washed for 15 minutes in water with Tween 80 and bleach at 0.05% and 0.15%, respectively [18]. Finally, tomatoes were rinsed thrice (10 minutes each) in distilled water. ...
Plant pathogenic fungi are the most important cause of losses in agriculture. In the face of the overuse of synthetic fungicides, natural products are an encouraging alternative to control these plant pathogenic fungi. In this study, we tested the antifungal capacity of metabolites produced by strains of the genus Streptomyces against the plant pathogenic fungi Alternaria alternata, Botrytis cinerea and Fusarium oxysporum. In addition, we investigated the feasibility of applying these metabolites in a postharvest setting for the control of B. cinerea on cherry tomato fruits. The results revealed the ability of the strains, especially Streptomyces netropsis, to inhibit the growth of plant pathogenic fungi and, in some cases, the sporulation of these fungi. In addition, we observed an interesting phenomenon in which Streptomyces strains physically encapsulated the mycelium of the fungi, which contributed to their inhibition. Finally, the protective activity of S. netropsis extract on Cherry tomato fruits infected with B. cinerea was demonstrated. In conclusion, this research opens the door to studies on the understanding of physical microbial interactions in natural environments and holds promise in agriculture, especially in the protection of agricultural products during the post-harvest stage as a safer and more sustainable alternative.
... Sin embargo, algunos estudios indican que no siempre destruyen la microflora y, además, organizaciones de la salud y del medio ambiente han expresado su preocupación por su empleo debido a la formación de residuos químicos en el agua de proceso que recaen en el medio ambiente, o por generar compuestos perjudiciales para la salud como trihalometanos (THM) y cloraminas, considerados tóxicos para el hígado y el riñón (Graham, 1997). Estos THM se forman por la reacción del cloro libre (HOCl, OCl -) con compuestos orgánicos y el nivel máximo tolerado de THM en el agua es de 100 mg L -1 (Garmendia y Vero, 2006). Surge así el interés por otras técnicas sostenibles y emergentes de desinfección que puedan reemplazar al cloro, proporcionando otros beneficios, como sucede con el ozono (O 3 ), el agua electrolizada, las radiaciones ionizantes o no, los antimicrobianos naturales, las bacteriocinas, los tratamientos térmicos, ciertos agentes químicos como el ácido peroxiacético y otros muchos (Artés et al., 2009). ...
La elaboración de hortalizas de IV Gama requiere de una etapa de desinfección que reduzca el crecimiento de microorganismos alterantes y patogénicos. En general, esta desinfección requiere de la adición de productos sanitizantes como el cloro o sus hipocloritos. Debido a que el cloro reacciona con otros compuestos orgánicos, dando lugar a la formación de subproductos halogenados perjudiciales para la salud como trihalometanos y cloraminas, las preocupaciones sobre la toxicidad de estos derivados han dado lugar al interés actual por utilizar productos alternativos y amigables con el medio ambiente. El interés por estos nuevos desinfectantes no solo se debe a su capacidad de inactivación frente a una amplia gama de microorganismos patógenos y deteriorantes, sino también a su capacidad para mantener la calidad sensorial del producto. Actualmente, existen diversas técnicas sostenibles y emergentes de desinfección que pueden reemplazar al cloro, proporcionando otros beneficios, como sucede con el ozono (O3), el agua electrolizada (AE), las radiaciones ionizantes o no, los antimicrobianos naturales, las bacteriocinas, los tratamientos térmicos, determinados agentes químicos como el ácido peroxiacético (AP) y otros muchos. En el presente trabajo revisaremos la eficacia del O3, AE y AP. Todos ellos han demostrado su eficacia microbicida con efecto frente a bacterias patógenas presentes en hortalizas de IV Gama.
... Escherichia coli (Garmendia y Vero, 2006 (García et al., 2008), con el objetivo de aumentar el tiempo de vida útil de la hortaliza de IV gama y de realizar una propuesta final efectiva y de fácil implementación. ...
RESUMEN Las hortalizas de IV gama constituyen un alimento de calidad, fresco y listo para el consumo. En Cuba esta técnica, aunque puede tener una alta demanda en la producción local de alimentos, no se encuentra muy explotada. Uno de los aspectos más importantes para su correcta implementación es mantener la calidad microbiológica. En el presente estudio se procesaron plantas de lechuga procedentes de un mercado agropecuario y se mantuvieron durante siete días entre 4-6 °C de temperatura. Se evaluó, con el Método de Diluciones Seriadas, la concentración de bacterias mesófilas aerobias, coliformes fecales y Salmonella después del procesamiento y a los tres, cinco y siete días de conservación y se clasificaron los aislados con mayor abundancia por su respuesta a la tinción de Gram. Además, se caracterizó la apariencia de la hortaliza procesada. A los tres días de conservación todos los tratamientos garantizaron una concentración microbiana inferior a 10 6 UFC g.tejido-1 , sin presencia de coliformes fecales y Salmonella. A los cinco días solamente aquellos donde se combinó en el lavado y desinfección agua y Alcamax e hipoclorito de sodio y ácido acético mantuvieron esta característica, aunque en el último caso se afectó la apariencia de la hortaliza. En los microorganismos purificados (17 aislados) predominaron los bacilos Gram positivos. Los resultados demostraron la posibilidad de disminuir la carga microbiana en la obtención de lechuga de IV gama con el empleo de sustancias químicas y con ello, la posibilidad de implementar esta técnica de procesamiento en Cuba. Palabras clave: calidad microbiológica, hortalizas, procesamiento mínimo Evaluation of microbiological quality of lettuce (Lactuca sativa L.) processed by IV Gama technique. ABSTRACT IV gama vegetables are a food of quality, fresh and ready to eat. In Cuba, this technique, that can have a big acceptation in the local production of food, it is not much exploited. One of the most important aspects for their correct implementation is to maintain the microbiological quality. In the present study were processed lettuce plants of the markets and they were maintained during seven days between 4-6 °C of temperature. It was evaluated by Serial Dilution Methods the concentration of aerobic mesophyll bacteria, _________________________________
El desarrollo de una región depende principalmente del aprovechamiento sostenible de sus recursos naturales y de su gente, es decir, del potencial regional condicionado por su medio ambiente, con miras al fortalecimiento del bienestar social y la conservación de sus recursos que requiere de enfoques particulares para lograr un verdadero desarrollo sostenible regional, destacando sus potencialidades. Uno de los factores de la producción sostenible de los bosques tropicales es la conservación de sus especies vegetales silvestres útiles, cuyo estado puede ser evaluado a través del conocimiento tradicional. Esta investigación tuvo como objetivo elaborar una bebida alcohólica tipo vino, a partir de frutos de hobo, Spondias mombin L., como una alternativa productiva en comunidades negras del Chocó, Colombia. Se preparó un jugo de pulpa de hobo, previa desinfección de las frutas a ser utilizadas. Se realizó una fermentación alcohólica con levadura comercial (Saccharomyces cerevisiae) y azúcar; se evaluaron las características físicas arrojadas durante el proceso de fermentación. El análisis del mosto permitió evidenciar un adecuado desarrollo del proceso de fermentación alcohólica, presentando un pH de 3,5, °Brix 18,3, GAP (grado alcohólico probable) 10% v/v y una densidad de 1.075 g/l. El proceso de transformación y elaboración del vino de hobo, a partir de la fermentación alcohólica, permitió obtener un vino dulce con características similares a las establecidas para otros vinos que se encuentran en el mercado.
Las nanopartículas son materiales que pueden llegar a medir entre 1 a 100 nm de longitud, y en la actualidad la propiedad antimicrobiana de las nanopartículas de plata es aprovechada por las industrias para la fabricación de productos de belleza y medicamentos. Las nanopartículas pueden ser sintetizadas a partir de plantas, algas o microorganismos, y también pueden ser obtenidas como productos de combustión. En este estudio se utilizaron extractos de las hojas de romero (Rosmarinus officinalis L.) para la síntesis de nanopartículas de plata (NPs-Ag) con la finalidad de producir un compuesto antimicrobiano para usarse como conservante de frutas. Las NPs-Ag se caracterizaron cualitativa y cuantitativamente mediante análisis fitoquímicos y espectroscopia UV-VIS, presentando una absorción en el rango de 389-418 nm, que corresponde a la resonancia de su plasmón superficial. Además, se empleó la microscopía electrónica de barrido para determinar el tamaño y morfología de las NPs-Ag, observándose una forma esférica de 10 nm de diámetro. Se emplearon dos cepas bacterianas en los ensayos antimicrobianos realizados, la gramnegativa (Escherichia coli) y la grampositiva (Staphylococcus aureus) para comprobar la actividad antimicrobiana de las NPs-Ag. Para E. coli se obtuvo una mejor actividad antibacteriana con un halo de inhibición de 3,21 mm. Posteriormente se usaron las NPs-Ag en manzanas para determinar su uso como conservante, usando la cera de abeja como control untada en la superficie de las frutas, observándose que las nanopartículas sintetizadas alargaron el tiempo de maduración de la frutas.
The effects of various treatments (i.e., the addition of a strain of Lactobacillus that produces antimicrobial agents, Lactobacillus casei IMPC LC34, its sterile permeate, and 0.5 or 1% lactic acid) on the growth of microorganisms associated with ready-to-use mixed salad vegetables were compared during refrigerated (8°C) storage. The addition of 3% culture permeate to mixed salads reduced the total mesophilic bacteria counts from 6 to 1 log CFU/g, and suppressed coliforms, enterococci, and Aeromonas hydrophila after 6 days of storage at 8°C. A similar effect was shown when the L. casei culture was inoculated in the vegetables. One percent lactic acid had a bacteriostatic effect on the bacterial groups examined, except for total and fecal coliforms, which were reduced by about 2 and 1 log unit, respectively, while 0.5% lactic acid did not affect the indigenous microflora of the vegetables. The potential of these new hurdles to prevent the growth of spoilage and pathogenic bacteria in ready-to-use salad vegetables is suggested.
Curing lemons at 32 C in a water-saturated atmosphere was evaluated for control of green mold to determine the effects of curing time, delay of treatment, and surfactants on efficacy. Fruit were inoculated with Penicillium digitatum by wounding with a tool dipped in a suspension of 10(6) spores per milliliter. For fruit inoculated 18 h prior to treatment, curing 36-48 h was required for optimal disease control, In two of three experiments, curing for 48 h resulted in disease control comparable to dipping in 1 g of imazalil per liter. The curing treatment could be delayed 24 h after inoculation without reducing the effectiveness of the treatment. When fruit inoculated 24 h earlier were immersed in water containing sodium dodecylbenzenesulfonate (SDBS) at 1 g/L and then cured 18 h, decay control was improved by 41-73% compared to the water-dipped cured control. The viability of P. digilatum conidia and germlings on potato-dextrose agar (PDA) was not affected by incubation at 30 C for 24 h or by plating onto PDA containing 40 mu g of SDBS/ml. However, the combination of these two treatments resulted in mortalities of 66 and 92% for conidia and germlings, respectively, suggesting that the combination of these treatments was lethal.
In recent years, as a consequence of the increasing number of produce-related outbreaks of food-borne illness, greater attention has been given to interventions that kill or remove human pathogens on fresh produce. A key goal of washing and sanitizing treatments, therefore, is removal or inactivation of such pathogens. However, published information suggests that conventional washing and sanitizing methods, even using newer sanitizing agents, are not capable of reducing microbial populations by more than 90 or 99 %, although greater efficacy is required to assure product safety. The response of microorganisms to washing and sanitizing treatments will depend in part on the conditions of contamination that affect attachment and survival on produce surfaces. Major factors limiting decontamination efficacy include strength and rapidity of microbial attachment, inaccessibility of attachment sites, attachment and growth in cuts and punctures, internalization of microbial contaminants within plant tissues, and biofilm formation. The performance of conventional produce washing equipment and washing and sanitizing agents in reducing microbial loads is examined. Recent improvements in washing and sanitizing technology are described. New approaches to washing and sanitizing produce that overcome the barriers limiting human pathogen detachment and inactivation are examined.
The potential of citrus fruit curing for the control of green mold caused by Penicillium digitatum, and the impact of this treatment on stem-end rot caused by Lasiodiplodia theobromae were investigated. The optimum temperatures for mycelial growth of P digitatum and L. theobromae were about 25 and 30 degrees C, respectively. P digitatum did not grow at 35 degrees C, while L. theobromae did. Injuries of 'Valencia' oranges developed less green mold disease at 30 and 35 degrees C than at 25 degrees C or lower. Green mold incidences on 'Valencia' oranges treated at 21 degrees C (uncured control), 30 and 35 degrees C for 48 h were 51, 17.4, and 0%, respectively, for inoculated fruit, and 18.8, 11.4, and 0%, respectively, for wounded fruit after 2 weeks of storage at 21 degrees C. However, a significant increase in stem-end rot occurred at 35 degrees C when compared with 21 degrees C (uncured control). In two of three different tests, curing fruit at 35 degrees C for 48 h achieved better green mold control than a shorter curing time of 24 h. Curing 'Pineapple' oranges showed a similar or better efficacy for green mold control than imazalil at 500 and 1,000 ppm applied by either dip or packingline drip. The combination of thiabendazole drench (500 ppm) and curing of wounded 'Valencia' oranges and inoculated 'Flame' grapefruit reduced both green mold and stem-end rot by more than 93%. This study suggests that curing (35 degrees C for 48 h) could be integrated into the current Florida citrus packing system to effectively control postharvest decays.
The effect of ozone on post-harvest decay of table grapes was studied both with regard to its effectiveness and its possible mode of action. Ozone concentrations fell rapidly upon contact with organic matter and the amount which reacted with grape berries and the microflora on their surface was about 0.1mgg-1, when supplied at a rate of 8mgmin-1for 20min. The dose applied could be increased by longer periods of exposure, but symptoms of toxicity were observed on certain cultivars. The number of colony forming units (cfu) of fungi, yeasts and bacteria naturally present on the berry surface was considerably reduced by a 20min exposure to ozone. Ozone treatments significantly reduced the extent of berry decay caused by fungi following cold storage and increased shelf-life. A significant decrease in decay was observed in berries that were treated with ozone either before or after being inoculated withRhizopus stolonifer.This finding indicates that, in addition to its sterilizing effect, ozone also induced resistance to post-harvest decay development. The phytoalexins resveratrol and pterostilbene were elicited by ozone treatments, at levels similar to those produced by uv-c irradiation. Resveratrol accumulated in greater quantities than pterostilbene. Inoculation withR. stoloniferin addition to ozone treatment, raised the levels of both stilbenes even more. Exposing berries to ozone was almost as effective as SO2fumigation for the control of storage decay caused byR. stoloniferand no deleterious effects were observed on the appearance of the grape cluster. Ozone treatments can therefore be considered as a possible substitute for SO2fumigation for the control of post-harvest fungal decay.
Penicillium expansum is one of the main postharvest pathogens of apples in Israel. Heating apple fruit inoculated with P. expansum for 96 h at 38°C completely inhibited decay development. Fruit held for 24 h at 42°C or 12 h at 46°C had significantly reduced decay after an additional 14 days incubation at 20°C, compared with unheated inoculated control fruit. Mycelial growth and percentage spore germination in vitro were inversely proportional to length of time of exposure to various temperatures. The ET50 for spore germination was 42, 34 and 20 h at 38, 42 and 46°C, respectively, while the ET50 for mycelial growth was 48, 44 and 36 h at those temperatures. When Penicillium spores were incubated on crude extract prepared from the peel of apple fruits held 4 days at 38°C, germ tube elongation was significantly reduced, while the walls of the tubes were thicker, compared with germ tubes from spores incubated on crude extract prepared from peel of non-heated fruit. The evidence presented here supports the hypothesis that the effect of heating on the decay of apples caused by P. expansum is not only the result of direct inhibition of fungal germination and growth by high temperature, but is also partly due to the formation of an inhibitory substance in the heated peel.