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Fungi are widely disseminated in the environment and are major food contaminants, colonizing plant tissues throughout the production chain, from preharvest to postharvest, causing diseases. As a result, grain development and seed germination are affected, reducing grain quality and nutritional value. Some fungal species can also produce mycotoxins, toxic secondary metabolites for vertebrate animals. Natural compounds, such as essential oils, have been used to control fungal diseases in cereal grains due to their antimicrobial activity that may inhibit fungal growth. These compounds have been associated with reduced mycotoxin contamination, primarily related to reducing toxin production by toxigenic fungi. However, little is known about the mechanisms of action of these compounds against mycotoxigenic fungi. In this review, we address important information on the mechanisms of action of essential oils and their antifungal and antimycotoxigenic properties, recent technological strategies for food industry applications, and the potential toxicity of essential oils.
Assuntos
Micotoxinas , Óleos Voláteis , Animais , Grão Comestível/química , Óleos Voláteis/farmacologia , Contaminação de Alimentos/análise , Micotoxinas/análise , FungosRESUMO
In this study, the probability of occurrence of fumonisins in corn in the states of greatest production in Brazil was determined. The data were analyzed through quantitative risk analysis using the Monte Carlo simulation. The results indicated that there is a strong correlation between fumonisins contamination levels and the geographical region due to the influence of climatic characteristics, with temperature having the main influence. The Southern states presented higher risks of occurrence and concentration levels of fumonisins in corn due to the temperate climate with lower average temperature and higher relative humidity and precipitation indices. Cultivation in the best season indicates a significant reduction in the production of fumonisins when this period was evaluated, with average concentration levels up to 42% lower. The generated data are important for regulatory agencies and the agricultural sector, which needs to be aware that the chance of success in grain production depends on efficient planning of the growing season, mainly concerning the climatic conditions to which it is subject to minimize the risks.
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Alkalization is a step of cocoa processing and consists of the use of alkali and high temperature to improve the sensorial and technological qualities of cocoa. Intense food processing can select spores, which can compromise safety and quality of the final product. Thus, the aim of this study was to evaluate the fate of B. cereus and G. stearothermophilus spores during the alkalization of pre-roasted (Pr) nibs (held at 120⯰C) and unroasted (Ur) nibs (held at 90⯰C) using potassium carbonate (0, 2, 4 and 6% w/w). In all conditions, log-linear inactivation kinetics with a tail was observed. The inactivation rate (kmax) for B. cereus varied from 0.065 to 1.67 min-1, whereas the kmax for G. stearothermophilus varied from 0.012 to 0.063 min-1. For both microorganisms, the lowest kmax values were observed during Ur nibs alkalization. The carbonate concentration increase promoted kmax values reduction. The highest tail values were observed for G. stearothermophilus in Ur nibs alkalization, reaching 3.04 log spores/g. Tail formation and low kmax values indicated that cocoa alkalization does not cause significant reductions on bacterial spore population. Therefore, the microbiological control should be primarily ensured by the raw material quality and by avoiding recontamination in the cocoa chain.
Assuntos
Álcalis/química , Bacillus cereus/crescimento & desenvolvimento , Cacau/química , Cacau/microbiologia , Geobacillus stearothermophilus/crescimento & desenvolvimento , Viabilidade Microbiana/efeitos dos fármacos , Carbonatos/farmacologia , Manipulação de Alimentos , Microbiologia de Alimentos , Temperatura Alta , Potássio/farmacologia , Esporos BacterianosRESUMO
Artisanal raw milk cheeses are highly appreciated dairy products in Brazil and ensuring their microbiological safety has been a great need. This study reports the isolation and characterization of lactic acid bacteria (LAB) strains with anti-listerial activity, and their effects on Listeria monocytogenes during refrigerated shelf-life of soft Minas cheese and ripening of semi-hard Minas cheese. LAB strains (nâ¯=â¯891) isolated from Minas artisanal cheeses (nâ¯=â¯244) were assessed for anti-listerial activity by deferred antagonism assay at 37⯰C and 7⯰C. The treatments comprised the production of soft or semi-hard Minas cheeses using raw or pasteurized milk, and including the addition of selected LAB only [Lactobacillus brevis 2-392, Lactobacillus plantarum 1-399 and 4 Enterococcus faecalis (1-37, 2-49, 2-388 and 1-400)], L. monocytogenes only, selected LAB co-inoculated with L. monocytogenes, or without any added cultures. At 37⯰C, 48.1% of LAB isolates showed anti-listerial capacity and 77.5% maintained activity at 7⯰C. Selected LAB strains presented a bacteriostatic effect on L. monocytogenes in soft cheese. L. monocytogenes was inactivated during the ripening of semi-hard cheeses by the mix of LAB added. Times to attain a 4 log-reduction of L. monocytogenes were 15 and 21 days for semi-hard cheeses produced with raw and pasteurized milk, respectively. LAB with anti-listerial activity isolated from artisanal Minas cheeses can comprise an additional barrier to L. monocytogenes growth during the refrigerated storage of soft cheese and help shorten the ripening period of semi-hard cheeses aged at ambient temperature.
Assuntos
Antibiose , Queijo/microbiologia , Lactobacillales/fisiologia , Listeria monocytogenes/crescimento & desenvolvimento , Brasil , Queijo/análise , Contaminação de Alimentos/análise , Contaminação de Alimentos/prevenção & controle , Microbiologia de Alimentos , Lactobacillales/genética , Lactobacillales/isolamento & purificação , Listeria monocytogenes/fisiologia , Temperatura , Fatores de TempoRESUMO
Sodium chloride is traditionally used as a food additive in food processing. However, because of its high sodium content, NaCl has been associated with chronic diseases. Margarine is a popular product that is used in several preparations, but it includes high sodium content; therefore, it is among the products whose sodium content should be reduced. Thus, the objective of this study was to produce margarines with reduced sodium content prepared using a salt mixture. The following 4 margarine formulations were prepared: Formulation A (control - 0% sodium reduction), Formulation B (20.8% less sodium), Formulation C (33.0% less sodium) and Formulation D (47.4% less sodium). The low sodium formulations were produced using a salt mixture consisting of NaCl, KCl, and monosodium glutamate at different concentrations. The margarines were evaluated using an acceptance test and descriptive tests: time-intensity and temporal dominance of sensations. The mixture used is a good alternative for preparing low sodium margarine because the low sodium formulations feature equal salinity and do not produce a strange or bad taste. Furthermore, it may be possible to prepare margarines with up to 47.4% less sodium and that are acceptable to consumers.
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Manipulação de Alimentos/métodos , Margarina/análise , Sensação , Cloreto de Sódio na Dieta/administração & dosagem , Paladar , Fatores de TempoRESUMO
The production of whole-liquid eggs is of significant economic and nutritional importance. This study aimed to assess the phenotypic and genotypic diversity of mesophilic aerobic spore-forming bacteria (nâ¯=â¯200) isolated from pasteurized whole liquid egg and liquid egg yolk. The majority of the isolates were identified as belonging to the genera Bacillus (86â¯%), followed by Brevibacillus (10â¯%) and Lysinibacillus (4â¯%). For the phenotypic characterization, isolates were subjected to various heat shocks, with the most significant reductions observed at 80⯰C/30â¯min and 90⯰C/10â¯min for isolates recovered from raw materials. On the other hand, the decrease was similar for isolates recovered from raw material and final product at 100⯰C/5 min and 110⯰C/5 min. Genotypic genes related to heat resistance (cdnL, spoVAD, dacB, clpC, dnaK, and yitF/Tn1546) were examined for genotypic characterization. The dnaK gene showed a positive correlation with the highest thermal condition tested (110⯰C/5 min), while 100⯰C/5 min had the highest number of positively correlated genes (clpC, cdnL, yitF/Tn1546, and spoVAD). Whole Genome Sequencing of four strains revealed genes related to sporulation, structure formation, initiation and regulation, stress response, and DNA repair in vegetative cells. The findings of this study indicate that these mesophilic aerobic spore-forming bacteria may adopt several strategies to persist through the process and reach the final product. As the inactivation of these microorganisms during egg processing is challenging, preventing raw materials contamination and their establishment in processing premises must be reinforced.
Assuntos
Bacillus , Esporos Bacterianos , Esporos Bacterianos/genética , Bactérias , Cognição , Gema de OvoRESUMO
The increase in the fruit juice consumption and the interest in clean label products boosted the development and evaluation of new processing technologies. The impact of some emerging non-thermal technologies in food safety and sensory properties has been evaluated. The main technologies applied in the studies are ultrasound, high pressure, supercritical carbon dioxide, ultraviolet, pulsed electric field, cold plasma, ozone and pulsed light. Since there is no single technique that presents high potential for all the evaluated requirements (food safety, sensory, nutritional and the feasibility of implementation in the industry), the search for new technologies to overcome the limitations is fundamental. The high pressure seems to be the most promising technology regarding all the aspects mentioned. Some of the outstanding results are 5 log reduction of E. coli, Listeria and Salmonella, 98.2% of polyphenol oxidase inactivation and 96% PME reduction. However its cost can be a limitation for industrial implementation. The combination of pulsed light and ultrasound could overcome this limitation and provide higher quality fruit juices. The combination was able to achieve 5.8-6.4 log cycles reduction of S. Cerevisiae, and pulsed light is able to obtain PME inactivation around 90%, 61.0 % more antioxidants, 38.8% more phenolics and 68.2% more vitamin C comparing to conventional processing, and similar sensory scores after 45 days at 4 °C comparing to fresh fruit juice. This review aims to update the information related to the application of non-thermal technologies in the fruit juice processing through systematic and updated data to assist in industrial implementation strategies.
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Sucos de Frutas e Vegetais , Micotoxinas , Manipulação de Alimentos/métodos , Escherichia coli , Saccharomyces cerevisiaeRESUMO
This study compared the resistance to different desiccation conditions of 190 Salmonella enterica strains previously isolated from the soybean meal production chain and belonging to 23 serovars. Additionally, the post-rehydration growth and heat tolerance of the strains previously exposed to desiccation were determined. Variability in desiccation resistance was observed both within and between serovars. Strains belonging to S. Havana and S. Schwarzengrund serovars were the most resistant, regardless of storage condition. The drying temperature (20 °C and 30 °C) did not influence the desiccation resistance of the Salmonella strains. On the other hand, increasing drying time from 1 to 7 days reduced Salmonella counts. The origin (isolation sources) also influenced the desiccation resistance of the Salmonella strains. The growth of the Salmonella strains after rehydration varied considerably depending on the drying conditions and incubation temperature during cultivation. An increase in the time and temperature of drying led to a reduction in population of most Salmonella strains after rehydration. Salmonella strains previously desiccated also showed differences in the heat tolerance in all temperature-time binomials tested. Some strains were highly resistant to heat tolerance conditions, presenting <1 log CFU/mL reduction from the initial population. The results obtained in this study suggest that the strategies to mitigate Salmonella in low-aw foods must consider the existence of high-stress resistant strains and their multiple-stress adaptability profiles, including effects of processing, food composition, and storage conditions.
Assuntos
Salmonella enterica , Termotolerância , Glycine max , Dessecação , HidrataçãoRESUMO
This study aimed to determine Salmonella enterica occurrence along the soybean meal production chain (raw material, in-processing samples, final products, and in the environment of five processing plants), characterize the isolates, and assess the survival of Salmonella Senftenberg 775W in soybeans stored under different temperature conditions. Among 713 samples analyzed, 12.9% (n = 92) were positive for Salmonella enterica. Dust collected inside and outside processing plants (n = 148) comprised the samples with the highest positivity for Salmonella enterica, 47.3%. The occurrence of Salmonella enterica varied among the different processing plants. Twenty-nine (n = 29) Salmonella serotypes were isolated, with S. Mbandaka as the most frequent serotype, whereas S. Typhimurium was mainly linked to final product samples (soybean meal). S. Senftenberg 775W did not survive for a long time in soybean stored at 20-37 °C, but at 20 °C, cells were viable for more than 60 days. This study suggests that soybean meal may harbor Salmonella serotypes related to foodborne disease outbreaks in humans and can be responsible for Salmonella introduction into livestock and, consequently, in foods of animal origin. This study provides crucial data on contamination pathways of Salmonella in the soybean production chain, contributing to the understanding of Salmonella epidemiology which is strategic for the development of preventive and control measures to reduce the burden of salmonellosis linked to products of animal origin.
Assuntos
Intoxicação Alimentar por Salmonella , Infecções por Salmonella , Salmonella enterica , Animais , Gado , Glycine maxRESUMO
Clostridium difficile is a strict anaerobic spore-forming bacterium, and an increasingly common nosocomial pathogen. The U.S. Environmental Protection Agency (EPA) is responsible for the registration of disinfectants, including products designed to treat environmental surfaces contaminated with spores of C. difficile. Product efficacy data are required for registration; however, there is a lack of methodology for generating high-quality spore suspensions for evaluating product performance. As such, a study was carried out to select a suitable C. difficile strain and to develop a stand-alone method to prepare a spore suspension that meets specific criteria necessary for quantitative testing of disinfectants. The criteria are: (1) a spore titer of > 8 log10/mL, (2) > or = 90% spores to vegetative cells, and (3) resistance of spores (determined by viability) to 2.5 M hydrochloric acid (HCl). Several strains of C. difficile (toxigenic and nontoxigenic) were grown on various media (solid and liquid) for varying lengths of time to determine the best combination of incubation conditions and media to optimize spore production and quality. Once the spore production procedure was optimized, a toxigenic strain of C. difficile [American Type Culture Collection (ATCC) 43598] was selected for use in trials to verify repeatability from one production run to the next. The spore suspension was initiated by spreading vegetative cells of C. difficile (ATCC 43598) on CDC anaerobic 5% sheep blood agar plates and incubating for 7-10 days at 36 +/- 1 degrees C under anaerobic conditions. Spores were harvested when > or = 90% of the cells converted to spores as determined by observation using phase-contrast microscopy. The spores were washed three times with saline-Tween-80, resuspended in cold deionized water, heated to 70 degrees C for 10 min, evaluated microscopically for quality, and enumerated on cycloserine-cefoxitin-fructose agar containing horse blood and taurocholate. The spore suspension was used to inoculate brushed stainless steel carriers (1 cm in diameter) with and without a soil load in accordance with the Standard Quantitative Carrier Disk Test Method (ASTM E-2197-02) to determine carrier load. Once it was determined that > 6 log10 spores/carrier could be recovered, spores were evaluated for resistance to HCI. The sporulation method presented in this report is simple and repeatable and results in spore suspension of high titer (> 8 log10/mL) and quality (> or = 90% spores to vegetative cells) that met acid resistance criteria (spores were resistant to 2.5 M HCI for 10 min). In addition, recovery from brushed stainless steel carriers with and without soil load was > 6 log10 spores/carrier. A 6 log10 performance standard was set forth in the EPA's interim guidance for generating data to support a label claim for effectiveness against C. difficile spores on hard, nonporous surfaces. This precollaborative investigation successfully demonstrated the use of a methodology for in vitro production of C. difficile spores (ATCC 43598) necessary for conducting efficacy tests. A proposal will be submitted to the AOAC INTERNATIONAL Methods Committee on Antimicrobial Efficacy Testing for a collaborative study; see Appendix.
Assuntos
Clostridioides difficile/efeitos dos fármacos , Desinfetantes/farmacologia , Esporos Bacterianos/efeitos dos fármacos , Clostridioides difficile/isolamento & purificação , Clostridioides difficile/fisiologia , Microbiologia Ambiental , Testes de Sensibilidade Microbiana , Técnicas Microbiológicas , Esporos Bacterianos/isolamento & purificação , Estados Unidos , United States Environmental Protection AgencyRESUMO
The consumption of artisanal beer has increased worldwide. Artisanal beers can include malted or unmalted wheat, maize, rice and sorghum, in addition to the basic ingredients. These grains can be infected by toxigenic fungi in the field or during storage and mycotoxins can be produced if they find favorable conditions. Mycotoxins may not be eliminated throughout the beer brewing and be detected in the final product. In addition, modified mycotoxins may also be formed during beer brewing. This review compiles relevant information about mycotoxins produced by Aspergillus, Fusarium and Penicillium in raw material of artisanal beer, as well as updates information about the production and fate of mycotoxins during the beer brewing process. Findings highlight that malting conditions favor the production of mycotoxins by the fungi contaminating cereals. Therefore, good agricultural and postharvest mitigation strategies are the most effective options for preventing the growth of toxigenic fungi and the production of mycotoxins in cereals. However, the final concentration of mycotoxin in artisanal beer is difficult to predict as it depends on the initial concentration contained in the raw material and the processing conditions. The current lack of limits of mycotoxins in artisanal beer underestimates possible risks to human health. In addition, modified mycotoxins, not detected by conventional methods, may be formed in artisanal beers. Maximum tolerated limits for these contaminants must be urgently established based on scientific data about transfer of mycotoxins throughout the artisanal beer brewery process.
Assuntos
Fusarium , Micotoxinas , Cerveja/análise , Grão Comestível/química , Contaminação de Alimentos/análise , Humanos , Micotoxinas/análiseRESUMO
The increased consumption of plant-based foods has intensified the concern related to mycotoxin intoxication. This study aimed to investigate the effect of selected lactic acid bacteria (LAB) strains on the growth of Aspergillus parasiticus NRRL 2999 and its production of aflatoxin (AF). The ability of the heat-killed (100°C for 1 h) LAB strains to bind aflatoxin M1 (AFM1) in milk and aflatoxin B1 (AFB1), ochratoxin A (OTA), and zearalenone (ZEN) in potassium phosphate buffer (PPB) was also evaluated in vitro. Ten LAB strains were tested individually, by inoculating them simultaneously with the fungus or after incubation of the fungus for 24 or 48 h at 25°C. Double layer yeast extract sucrose (YES) agar, de Man Rogosa and Sharpe (MRS) agar, and YES broth were incubated for 7 days at 25°C to follow the development of the fungus. Levilactobacillus spp. 3QB398 and Levilactobacillus brevis 2QB422 strains were able to delay the growth of A. parasiticus in YES broth, even when these strains were inoculated 24 h after the fungus. The inhibitory effect of these LAB strains was confirmed by the reduction of fungus colony size, suggesting dominance of LAB by competition (a Lotka-Voltera effect). The production of AFB1 by A. parasiticus was inhibited when the fungus was inoculated simultaneously with Lactiplantibacillus plantarum 3QB361 or L. plantarum 3QB350. No AFB1 was found when Levilactobacillus spp. 2QB383 was present, even when the LAB was inoculated 48 h after the fungus. In binding studies, seven inactivated LAB strains were able to promote a reduction of at least 50% the level of AFB1, OTA, and ZEN. This reduction varied depending on the pH of the PPB. In milk, however, only two inactivated LAB strains were able to reduce AFM1, with a reduction of 33 and 45% for Levilactobacillus spp. 3QB398 (Levilactobacillus spp.) and L. brevis 2QB422, respectively. Nevertheless, these results clearly indicate the potential of using LAB for mycotoxin reduction.
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Yeasts are able to reduce the levels of ochratoxin A in fermentative processes; and, through their enzymatic complex, these micro-organisms are also capable of forming modified mycotoxins. These mycotoxins are often underreported, and may increase health risks after ingestion of contaminated food. In this sense, this study aims to evaluate whether the presence of ochratoxin A influences yeast growth kinetic parameters and to elucidate the formation of modified ochratoxin by Saccharomyces cerevisiae strains during fermentation. Three S. cerevisiae strains (12â¯M, 01â¯PP, 41â¯PP) were exposed to OTA at the concentrations of 10, 20 and 30⯵g/L. The Baranyi model was fitted to the growth data (Log CFU/mL), and the identification of modified ochratoxins was performed through High Resolution Mass Spectrometry. The presence of ochratoxin A did not influence the growth of S. cerevisiae strains. Four pathways were proposed for the metabolization of OTA: dechlorination, hydrolysis, hydroxylation, and conjugation. Among the elected targets, the following were identified: ochratoxin α, ochratoxin ß, ochratoxin α methyl ester, ochratoxin B methyl ester, ethylamide ochratoxin A, ochratoxin C, hydroxy-ochratoxin A, hydroxy-ochratoxin A methyl ester, and ochratoxin A cellobiose ester. These derivatives formed from yeast metabolism may contribute to the occurrence of underreporting levels of total mycotoxin in fermented products.
Assuntos
Ocratoxinas/metabolismo , Saccharomyces cerevisiae/efeitos dos fármacos , Saccharomyces cerevisiae/crescimento & desenvolvimento , Biotransformação , Sobrevivência Celular/efeitos dos fármacos , Cinética , Modelos Biológicos , Ocratoxinas/análiseRESUMO
A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has not been fixed in the paper.
RESUMO
Modified mycotoxins are metabolites that normally remain undetected during the testing for parent mycotoxin. These modified forms of mycotoxins can be produced by fungi or generated as part of the defense mechanism of the infected plant. In some cases, they are formed during food processing. The various processing steps greatly affect mycotoxin levels present in the final product (free and modified), although the results are still controversial regarding the increase or reduction of these levels, being strongly related to the type of process and the composition of the food in question. Evidence exists that some modified mycotoxins can be converted into the parent mycotoxin during digestion in humans and animals, potentially leading to adverse health effects. Some of these formed compounds can be even more toxic, in case they have higher bioaccessibility and bioavailability than the parent mycotoxin. The modified mycotoxins can occur simultaneously with the free mycotoxin, and, in some cases, the concentration of modified mycotoxins may exceed the level of free mycotoxin in processed foods. Even though toxicological data are scarce, the possibility of modified mycotoxin conversion to its free form may result in a potential risk to human and animal health. This review aims to update information on the formation, detection, occurrence, and toxic effects caused by modified mycotoxin.
Assuntos
Micotoxinas/química , Micotoxinas/toxicidade , Animais , Contaminação de Alimentos , Manipulação de Alimentos , Microbiologia de Alimentos , HumanosRESUMO
Aspergillus carbonarius and Aspergillus niger are the main responsible fungi for the accumulation of ochratoxin A (OTA) in wine grapes. Some strains are able to convert the parent mycotoxin into other compounds by means of hydrolysis and/or conjugation reactions through their defense mechanisms and enzymatic activity, leading to the formation of a modified mycotoxin. Thus, the variability of growth and metabolite production are inherent to the strain, occurring distinctively even when submitted to similar conditions. In this sense, this contribution aimed at determining the variability in multiplication and production of OTA by strains of A. carbonarius and A. niger isolated from grapes, as well as investigating the formation of modified mycotoxins. Strains were incubated in grape-based medium, and the diameter of the colonies measured daily. The determination of OTA was performed by high-performance liquid chromatography and the identification of modified mycotoxins was carried out using high-resolution mass spectrometry. Variabilities in terms of growth and OTA production were assessed across five different strains. Peak production of OTA was detected on day 15, and a decline on day 21 was observed, indicating that the observed reduction may be associated with the degradation or modification of the OTA over time by the fungus. Ethylamide ochratoxin A, a modified mycotoxin identified in this study, provides evidence that there may be underreporting of total mycotoxin levels in food, increasing uncertainty concerning health risks to the population.
Assuntos
Aspergillus/crescimento & desenvolvimento , Aspergillus/metabolismo , Meios de Cultura/química , Ocratoxinas/metabolismo , Aspergillus/isolamento & purificação , Cromatografia Líquida de Alta Pressão , Espectrometria de Massas , Técnicas Microbiológicas , Fatores de Tempo , Vitis/microbiologiaRESUMO
Ochratoxin A is the main contaminant mycotoxin of grapes produced mainly by Aspergillus niger and Aspergillus carbonarius. Besides, it is possible that the formation of modified mycotoxin occurs through the plant defense mechanism or also by fungus actions itself. The objective of this study was to evaluate the influence of grape variety and maturation stage on the formation of OTA and modified mycotoxin. The determination of OTA was performed by high-performance liquid chromatography, and a high-resolution mass spectrometry was used for the detection of modified ochratoxin. A positive correlation was observed between the following grapes physicochemical parameters: pH, total soluble solids, total glycosides in glucose, total anthocyanin, and OTA levels produced by A. niger and A. carbonarius. Therefore, the higher the concentrations of these parameters, the greater the production of mycotoxin in grapes. Among the elected targets, we identified the 14-decarboxy-ochratoxin A in Muscat Italia variety at veraison and 15 days after the beginning of veraison stages; and ethylamide-ochratoxin A as a biomarker in the Syrah variety at the ripeness stage.
Assuntos
Aspergillus niger/metabolismo , Aspergillus/metabolismo , Frutas/química , Ocratoxinas/análise , Vitis/crescimento & desenvolvimento , Cromatografia Líquida de Alta Pressão , Contaminação de Alimentos/análise , Frutas/classificação , Frutas/crescimento & desenvolvimento , Frutas/microbiologia , Espectrometria de Massas , Ocratoxinas/metabolismo , Vitis/química , Vitis/classificação , Vitis/microbiologia , Vinho/análiseRESUMO
AOAC Method 966.04, the Sporicidal Activity of Disinfectants Test, is a carrier-based test that provides a qualitative measure of product efficacy against spores of Bacillus subtilis and Clostridium sporogenes. For regulatory purposes, Method 966.04 is accepted by the U.S. Environmental Protection Agency (EPA) and the U.S. Food and Drug Administration (FDA) for the generation of product performance data for sporicides and sterilants. In this study, we report on findings associated with proposed improvements (modifications) to the Clostridium component of the method. Egg meat medium (EMM), the culture medium for C. sporogenes currently specified in the method, is no longer commercially available and finding a suitable replacement is critical. In addition, the use of a nonstandardized extract of raw soil as an amendment to EMM, as stipulated in the current method, may result in a highly variable spore suspension. The primary focus of this study was to find replacements for EMM and soil extract. A carrier count procedure, the establishment of target carrier counts (spores/carrier), and a neutralization confirmation procedure were also evaluated. The study was limited to liquid products tested against Clostridium on a hard surface carrier (porcelain penicylinder). Spore suspensions of C. sporogenes were generated using: (1) EMM with soil extract (EMM/SE), (2) cooked meat medium with soil extract (CMM/SE), and (3) cooked meat medium with 5 microg/mL manganese sulfate (CMM/MnSO4). The titer of the spore suspension, carrier counts, resistance to hydrochloric acid (HCI), and efficacy against 3 liquid sporicidal agents were used to evaluate the potential of CMM and MnSO4 as replacements. The study was performed by the EPA Office of Pesticide Programs Microbiology Laboratory, Fort Meade, MD. Use of CMM/SE and CMM/MnSO4 resulted in comparable results for titer of spore suspensions (approximately 10(8) spores/mL) and carrier counts (approximately 3 x 10(6) spores/carrier). The carrier counts for the EMM/SE were approximately 1 log lower than CMM-based treatments; however, no attempt was made to dilute the CMM spore suspensions prior to carrier inoculation to reduce the carrier counts for CMM. Resistance of spores to 2.5 M HCI was acceptable across the 3 media types. Treatments for comparative efficacy testing were designed to provide a range of sporicidal activity, i.e., high and low efficacy treatments. Sodium hypochlorite (bleach), hydrogen peroxide/peracetic acid, and glutaraldehyde were used as test chemicals. The number of carriers resulting in growth (positive) for the low treatments for all 3 chemicals ranged from 9 to 59 out of 60 across the 3 media types--EMM exhibited fewer positives overall. The high efficacy treatments for sodium hypochlorite and hydrogen peroxide/peracetic acid yielded a range of 0 to 2 positives out of 60 across the 3 media. However, the high glutaraldehyde treatment generated 3, 20, and 20 positives out of 60 for the EMM/SE, CMM/SE, and CMM/MnSO4, respectively. The lower number of positive carriers for EMM/SE may be due to the reduced carrier counts. CMM, either with SE or MnSO4, appears to be a suitable replacement for EMM/SE. On the basis of the results of this study, the Study Director recommends that CMM/MnSO4 and the spore enumeration target carrier count and neutralization procedures be considered for collaborative study to officially modify the Clostridium x porcelain component of Method 966.04.