Susceptibility of Listeria monocytogenes strains to disinfectants and chlorinated alkaline cleaners at cold temperatures

Minimal inhibitory concentration (MIC), suspension and biofilm tests were used in evaluating the disinfecting efficacy of eight commercially available disinfectants and four chlorinated alkaline cleaners against 10 strains of Listeria monocytogenes at refrigerated temperatures. The adaptive response and cross-adaptation of L. monocytogenes to the disinfectants and chlorinated alkaline cleaners were investigated. The bactericidal components in the agents used were chlorine, quaternary ammonium compound (QAC), peracetic acid, ethanol and isopropanol. With some exceptions the disinfectants were efficient against the L. monocytogenes strains. One alkaline hypochlorite containing disinfectant was not efficient in the suspension and MIC tests at the lowest concentration recommended by the manufacturer. The chlorinated alkaline cleaners were effective against L. monocytogenes. A QAC-based disinfectant was found to be the least-effective agent on both glass bead-blasted polyethylene and stainless-steel surfaces. Adaptive and cross-adaptive responses of L. monocytogenes strains were observed towards the QAC-based agent, but over 2-fold increases to other agents were not observed. These results suggest that the adaptive responses of L. monocytogenes to disinfectants or chlorinated alkaline cleaners are of a minor concern.     

Heat shock and cold shock treatments affect the survival of Listeria monocytogenes and Salmonella Typhimurium exposed to disinfectants

The foodborne pathogens Listeria monocytogenes and Salmonella Typhimurium were subjected to heat shock at 48°C for 10 and 30 min, respectively, and then cold shocked at 15°C for 3 h. The effect of these shocks on the viability of test organisms exposed to chlorine dioxide and quaternary ammonium compounds was then determined. After exposure to the disinfectants, the viable population of each test organism, regardless of heat shock or cold shock treatment, decreased as the exposure period was extended. Both heat shock and cold shock treatments reduced the susceptibility of L. monocytogenes to both disinfectants at 25°C. However, for Salmonella Typhimurium, exposure to the chlorine dioxide disinfectant or quaternary ammonium compounds at 25°C significantly reduced (P < 0.05) survival of heat-shocked cells but significantly increased (P < 0.05) survival of cold-shocked cells compared with control cells. Survival of both L. monocytogenes and Salmonella Typhimurium generally was reduced after exposure to disinfectants at 40°C compared with 25°C.     

Efficacy of commonly used disinfectants for the inactivation of calicivirus on strawberry, lettuce, and a food-contact surface

Norwalk and Norwalk-like viruses (NLVs) are important causes of foodborne gastroenteritis in restaurant-related outbreaks. Efficacy of common disinfection methods against these viruses on food-contact surfaces and fresh produce is not known partially because of their nonculturability. Seven commercial disinfectants for food-contact surfaces and three sanitizers for fruits and vegetables were tested against cultivable feline calicivirus (FCV). Disks of stainless steel, strawberry, and lettuce were contaminated with known amounts of FCV. The disinfectants were applied at one, two, and four times the manufacturer's recommended concentrations for contact times of 1 and 10 min. The action of disinfectant was stopped by dilution, and the number of surviving FCVs was determined by titration in cell cultures. An agent was considered effective if it reduced the virus titer by at least 3 log10 from an initial level of 10(7) 50% tissue culture infective dose. None of the disinfectants was effective when used at the manufacturer's recommended concentration for 10 min. Phenolic compounds, when used at two to four times the recommended concentration, completely inactivated FCV on contact surfaces. A combination of quaternary ammonium compound and sodium carbonate was effective on contact surfaces at twice the recommended concentration. Rinsing of produce with water alone reduced virus titer by 2 log10. On artificially contaminated strawberry and lettuce, peroxyacetic acid and hydrogen peroxide was the only effective formulation when used at four times the manufacturers' recommended concentration for 10 min. These findings suggest that FCV and perhaps NLVs are very resistant to commercial disinfectants. However, phenolic compounds at two to four times their recommended concentrations appear to be effective at decontaminating environmental surfaces and may help control foodborne outbreaks of calicivirus in restaurants.     

Comparison of chlorine and peroxyacetic-based disinfectant to inactivate Feline calicivirus, Murine norovirus and Hepatitis A virus on lettuce

In recent years, raw fruits and vegetables have frequently been involved in foodborne transmission to humans of enteric viruses, particularly noroviruses and hepatitis A virus (HAV). Although viral contamination can occur during all steps of food processing, primary production is a critical stage on which prevention measures must be focused to minimize the risk of infection to consumers. Postharvest sanitation may be a valid technological solution for decreasing the bacterial load on fresh raw material, but there is a lack of data concerning the effectiveness of this process on enteric viruses. In this study, we compared the survival of two human norovirus surrogates, the feline calicivirus (FCV), and the murine norovirus (MNV-1), and of HAV on lettuce after water washing with bubbles and with or without ultrasound, and washing with bubbles in the presence of active chlorine (15 ppm) or peroxyacetic acid-based disinfectant (100 ppm). Cell culture and quantitative RT-PCR assays were used to detect and quantify the viruses on the surface of the lettuce after the sanitizing treatments. Levels of viral inactivation on the lettuce leaves were not significantly different between washing with bubbles and washing with bubbles plus ultrasound and were not dependant on the quantification method. A simple washing without disinfectant resulted in a decrease of approximately 0.7 log units in the quantity of virus detected for HAV and FCV and of 1.0 log unit for MNV-1.In the experimental set-up including a washing step (with or without ultrasound) followed by washing for 2 min in the presence of disinfectants, 15 ppm of active chlorine was found more effective for inactivating FCV (2.9 log units) than HAV and MNV-1 (1.9 log units and 1.4 log units, respectively) whereas 100 ppm of peroxyacetic-based biocide was found effective for inactivating FCV (3.2 log units) and MNV-1 (2.3 log units), but not HAV (0.7 log units). Quantitative RT-PCR results indicated that the presence of viral RNA did not correlate with the presence of infectious viruses on disinfected lettuce, except for MNV-1 processed with chlorine (15 ppm). In comparison with water washing, a substantial additional decrease of genomic FCV titer (1.1 log units) but no significant reduction of the genomic titers of HAV and MNV-1 were found on lettuce treated with chlorine (15 ppm). No significant effect of the disinfection step of lettuce with peroxyacetic-based biocide (100 ppm peracetic acid) was found by qRT-PCR on all genomic viral titers tested. This study illustrates the necessity of determining the effectiveness of technological processes against enteric viruses, using a relevant reference such as HAV, in order to reduce the risk of hepatitis and gastroenteritis by exposure to vegetables.     

Adaptive and cross-adaptive responses of persistent and non-persistent Listeria monocytogenes strains to disinfectants

Persistent and non-persistent Listeria monocytogenes strains were tested for initial resistance and adaptive and cross-adaptive responses towards two quaternary ammonium compounds, alkyl-benzyl-dimethyl ammonium chloride and n-alkyldimethyl ethylbenzyl ammonium chloride, one tertiary alkylamine, 1,3-propanediamine-N-(3-aminopropyl)N-dodecyl, sodium hypochlorite and potassium persulphate. The initial resistance of two persistent and two non-persistent L. monocytogenes strains was observed to differ. Both types of strains adapted after a 2-h sublethal exposure to the quaternary ammonium compounds and the tertiary alkylamine, the highest increase in the minimum inhibitory concentration (MIC) being 3-fold. Progressively increasing disinfecting concentrations at 10 and 37 degrees C resulted in adaptation of L. monocytogenes to all disinfectants except potassium sulphate. The highest observed increase in MIC was over 15-fold, from 0.63 to 10 microg/ml of n-alkyldimethyl ethylbenzyl ammonium chloride. All strains reached approximately similar MICs. Stability of the increased resistance was tested by measuring MICs every seventh day for 28 days. The increased resistance to sodium hypochlorite disappeared in 1 week, but the quaternary ammonium compounds and the tertiary alkylamine showed increased resistance for 28 days. These results suggest that cellular changes due to adaptive responses continue to have an effect on the resistance some time after the exposure. All disinfectants were shown to cause cross-adaptation of L. monocytogenes, the highest increase in MIC being almost 8-fold. The only agent that L. monocytogenes could not be shown to cross-adapt to was potassium persulphate which did, however, cause cross-adaptation to the other disinfectants. The mechanism behind these adaptive responses seemed to be non-specific as cross-adaptation was observed not only between related but also unrelated disinfectants. These findings suggest that sustaining high disinfectant effectiveness may be unsuccessful by rotation, even when using agents with different mechanisms of action.     

烟草漂浮育苗中剪叶工具消毒剂评价

为了指导烟草漂浮育苗中剪叶工具消毒剂的使用,采用半叶法测定了9种药剂对烟草病叶汁液中TMV的钝化效果,采用叶面喷雾法测定了药剂对烟草的药害浓度与药害症状。室温下一定浓度的药剂与TMV病叶汁液(终浓度为2万倍稀释液)混合时,30%有效氯漂白粉10倍液、98%磷酸三钠·12H₂O 10倍液、7%有效氯次氯酸钠150倍液、美国消毒剂125倍液和75%酒精,在3min内抑制率可达100%。除0.6%菌毒净较安全外,供试消毒剂在标签(常用)浓度下接触烟草叶片,产生较严重药害,症状因消毒剂种类不同,主要为褪绿斑点、坏死斑点和畸形。      

单核细胞增生李斯特菌对季铵盐类消毒剂耐药机制研究进展

单核细胞增生李斯特菌（Listeria monocytogenes,Lm）是一种重要的食源性致病菌,能够在食品加工环境中存活数月乃至数年之久。季铵盐类消毒剂在食品工业中的广泛应用导致Lm对此类消毒剂产生耐药性,从而影响消毒效果,增加食品被环境中Lm污染的机率。本文综述了Lm对季铵盐类消毒剂的耐药现状、耐药机制以及Lm对季铵盐类的适应性耐受机制的研究进展,阐明Lm对季铵盐类消毒剂耐药和适应性耐受机制,为指导食品从业人员合理规范化使用此类消毒剂、预防和控制食源性致病菌季铵盐类耐药提供理论依据,对保障食品质量安全也具有重要的现实意义。     

Development of an image system for the study of viable but non-culturable forms ofCampylobacter jejuniand its use to determine their resistance to disinfectants

A vital staining method incorporating fluorescence microscopy and image analysis has been developed to study the viable but non-culturable (VNC) form ofCampylobacter jejuni. This method was used to determine the comparative resistance of the culturable and VNC forms to proprietary disinfectants chosen to represent the four main groups of disinfectants used in food processing operations, namely quaternary ammonium compounds (QACs) and QACs combined with glutaraldehyde, amphoterics and chlorine. With all disinfectants except chlorine the culturable form was significantly more resistant than the VNC form. The resistance of the VNC form to chlorine may have significance for cleaning and decontamination in the food industry.     

Chlorine disinfection of produce to inactivate hepatitis A virus and coliphage MS2

Disinfection of produce is principally used to inactivate spoilage microbes and may also reduce the risk of consumer exposure to enteric pathogens. However, the rate and extent of enteric virus inactivation by free chlorine on produce has not been adequately characterized. Experiments were performed to determine the kinetics of free chlorine inactivation of hepatitis A virus (HAV) and the indicator virus coliphage MS2 on strawberries (SBs), cherry tomatoes (CTs), and head lettuce (HL). The oxidant demand of these produce items also was determined. When produce items were exposed to approximately 20 parts per million (ppm) solution of free chlorine for 5-10 min, HAV and MS2 were inactivated by 90-99% and in some cases virus inactivation was >/=99%. Exposure of strawberries to approximately 200 ppm free chlorine resulted in more rapid and extensive inactivation of both viruses. The produce items tested in this study exhibited a demand for chlorine which varied by produce type, and chlorine residuals declined over time. These results demonstrate the potential for chlorine to reduce the levels of infectious viruses on different produce types, but adequate contact time and chlorine residual are required to achieve maximum virus inactivation. The difference in chlorine demand between SBs, CTs, and HL suggests that varying disinfection practices are needed for the wide variety of processed fruits and vegetables. The inactivation kinetics of MS2 and HAV were similar, suggesting that MS2 and perhaps other similar bacterial viruses may be used as process indicators and surrogates for determining the disinfection efficacy of produce in the laboratory or in actual practice.     

Role of Disinfection in Food Industry

In industrialized countries, the epidemiology of infec- tious diseases with indirect transmission through water and foodstuffs has undergone considerable changes over the past decades with the almost total disappearance of some traditional pathogen microo…     

BACTERICIDAL EFFICIENCIES OF COMMERCIAL DISINFECTANTS AGAINST LISTERIA MONOCYTOGENES ON SURFACES

The efficiencies of potassium persulphate, isopropanol, hydrogen peroxide and peracetic acid, quaternary ammonium compound, hypochlorite, sodium dichloroisocyanurate, ethanol and phenol derivatives, tertiary alkylamines and dimethyl alamine betaine-based disinfectants and a hypochlorite-based disinfecting cleaning agent were evaluated against eight Listeria monocytogenes strains representing three different ribotypes. All the disinfectants were effective in a suspension test with an exposure time of 30 s at the lowest concentrations recommended by the manufacturer. The efficiencies on surfaces were reduced. However, on clean surfaces all the agents were considered effective when the exposure time was 5 min and the concentration was the average recommended by the manufacturer. Five of nine disinfectants and the disinfecting cleaning agent were considered effective in soiled conditions in the surface test. The most efficient agent was isopropanol-based and the least effective was the disinfectant containing tertiary alkylamine and dimethyl alamine betaine. Differences in bactericidal efficiencies of disinfectants against different L. monocytogenes strains on meat soiled surfaces were found.     

Impact of virus aggregation on inactivation by peracetic acid and implications for other disinfectants

Viruses in wastewater and natural environments are often present as aggregates. The disinfectant dose required for their inactivation, however, is typically determined with dispersed viruses. This study investigates how aggregation affects virus inactivation by chemical disinfectants. Bacteriophage MS2 was aggregated by lowering the solution pH, and aggregates were inactivated by peracetic acid (PAA). Aggregates were redispersed before enumeration to obtain the residual number of individual infectious viruses. In contrast to enumerating whole aggregates, this approach allowed an assessment of disinfection efficiency which remains applicable even if the aggregates disperse in post-treatment environments. Inactivation kinetics were determined as a function of aggregate size (dispersed, 0.55 and 0.90 μm radius) and PAA concentration (5-103 mg/L). Aggregation reduced the apparent inactivation rate constants 2-6 fold. The larger the aggregate and the higher the PAA concentration, the more pronounced the inhibitory effect of aggregation on disinfection. A reaction-diffusion based model was developed to interpret the experimental results, and to predict inactivation rates for additional aggregate sizes and disinfectants. The model showed that the inhibitory effect of aggregation arises from consumption of the disinfectant within the aggregate, but that diffusion of the disinfectant into the aggregates is not a rate-limiting factor. Aggregation therefore has a large inhibitory effect if highly reactive disinfectants are used, whereas inactivation by mild disinfectants is less affected. Our results suggest that mild disinfectants should be used for the treatment of water containing viral aggregates.     

Analysis of P. aeruginosa disinfectant sensitivity and microbial adhesions to worn cosmetic contact lenses

PurposeTo compare the sensitivity of two genotypes of P. aeruginosa to various disinfectant solutions and analyze the attached bacteria on worn cosmetic contact lenses (cosCLs).MethodsIn this prospective study, healthy volunteers wore etafilcon (brown), nelfilcon (gray), or hilafilcon (black) cosCLs and microbial adhesion analysis was performed. A rub-off test determined pigment dislodgement. Disinfectant sensitivity to Optifree Replenish (Alcon), Optifree Pure Moist (Alcon), Renu Fresh (Bausch & Lomb), and AoSept Plus (Ciba Vision) was tested at various disinfection times and compared between various genotypes and Type III secretion (T3S) system mutants.ResultsOf the 1152 cosCLs collected, 364 were culture positive (32%). The highest rate of culture-positive lens was hilafilcon (chi square, P = 0.0001). Hilafilcon also had a significantly greater number of isolates than etafilcon (P < 0.0001). Hilafilcon was the only lens to fail the rub-off test. Cytotoxic strains were significant more resistant to Renu Fresh than were invasive strains, even at 100% of recommended disinfection time (P = 0.0005). Of the tested disinfectants, Renu Fresh was significantly less effective in killing both genotypes of P. aeruginosa compared to AoSept Plus at all time points (25%, 50%, 75%, and 100% recommended disinfection time, P = 0.0001, 0.0001, 0.0005, and 0.0005, respectively). When the T3S system was dysfunctional, mutant strains were all susceptible to disinfectants (P = 0.0001 for both invasive and cytotoxic strains).ConclusionPseudomonas species is commonly found on cosCLs of asymptomatic individuals. Wearers of cosCLs that dislodge pigments may be predisposed to microbial contamination. Cytotoxic strains are more resistant to disinfectant solutions, especially to Renu Fresh. P. aeruginosa disinfectant resistance requires a functional T3S system.     

The Elimination of Listeria Monocytogenes Attached to Stainless Steel or Aluminum Using Multiple Hurdles

Ready‐to‐eat luncheon meats sliced in retail delis have been found to pose the greatest risk of foodborne illness from Listeria monocytogenes among all ready‐to‐eat foods. Slicers used in delis have many removable parts that are connected with seals and gaskets, with spaces, cracks and crevices that are difficult to clean adequately and may provide a niche for L. monocytogenes survival. Standard cleaning and sanitizing practices used by deli employees may not eliminate Listeria in these niches. Moist heat is known to be more effective against L. monocytogenes than dry heat at the same temperature and time. The study reported here investigated the effects of moist heat combined with quaternary ammonium compounds (5 or 10 ppm), chlorine (10 or 25 ppm) or peracetic acid (10 or 25 ppm) on inactivating L. monocytogenes attached to stainless steel or aluminum coupons cut from commercial deli meat slicer components. All sanitizers when used alone resulted in a 2‐ to 3‐log reduction of L. monocytogenes on stainless steel or aluminum surfaces, while moist heat alone resulted in a 3‐ to 4‐log reduction. When combined with heat the quaternary ammonium was used at 5 ppm, peracetic acid at 10 ppm and chlorine at 10 ppm. When the 2 lethal treatments were combined there was a 5‐ to7‐log reduction as compared to initial inoculation.     

Fungicidal effect of 15 disinfectants against 25 fungal contaminants commonly found in bread and cheese manufacturing.

Resistance of 19 mold and 6 yeast species to 15 commercial disinfectants was investigated by using a suspension method in which the fungicidal effect and germination time were determined at 20 degrees C. Disinfectants containing 0.5% dodecyldiethylentriaminacetic acid, 10 g of chloramine-T per 1, 2.0% formaldehyde, 0.1% potassium hydroxide, 3.0% hydrogen peroxide, or 0.3% peracetic acid were ineffective as fungicides. The fungicidal effect of quaternary ammonium compounds and chlorine compounds showed great variability between species and among the six isolates of Penicillium roqueforti var. roqueforti tested. The isolates of P roqueforti var. carneum, P. discolor, Aspergillus versicolor, and Eurotium repens examined were resistant to different quaternary ammonium compounds. Conidia and vegetative cells were killed by alcohols, whereas ascospores were resistant. Resistance of ascospores to 70% ethanol increased with age. Both P. roqueforti var. roqueforti and E. repens showed great variability of resistance within isolates of each species.     

Effectiveness of sanitation with quaternary ammonium compound or chlorine on stainless steel and other domestic food-preparation surfaces.

The relative ability of various materials used for domestic and/or food-service sinks and countertops to be sanitized was determined. Both smooth (unused) and abraded surfaces were tested by exposure to 200 mg of quaternary ammonium compound per liter or 200 mg of sodium hypochlorite per liter. Surface materials tested included mechanically polished (type 304, #4 finish) and electropolished stainless steel, polycarbonate, and mineral resin. Surfaces were prepared for testing by allowing attachment of a Staphylococcus aureus culture for 4 h to achieve an initial attached population of 10(4) to 10(5) CFU/cm2. The test procedure involved immersion of the surface in sanitizer solution followed by wiping with a sanitizer-saturated cloth. Residual staphylococci were detected by overlaying agar directly on the treated surface. Results indicated that the stainless steels and the smooth polycarbonate, which had 0.5 log CFU/cm2 or fewer of residual staphylococci, were more readily sanitized by quaternary ammonium compound than were either the mineral resin surfaces, which had nearly 2.0 log CFU/cm2 of residual staphylococci, or the abraded polycarbonate which had nearly 1.0 log CFU/cm2 of residual staphylococci. Chlorine was most effective on the mechanically polished stainless steel, the unabraded electropolished stainless steel, and the polycarbonate surfaces, reducing cell populations to less than 1.0 log CFU/cm2. Chlorine was less effective on abraded electropolished stainless steel and mineral resin surfaces, where populations remained greater than 1.0 log CFU/cm2. Sanitation with quaternary ammonium compound or chlorine reduced S. aureus populations more than 1,000-fold on all surfaces except unabraded mineral resin.     

Efficacy of amphoteric surfactant- and peracetic acid-based disinfectants on spores of bacillus cereus in vitro and on food premises of the German armed forces

In mass catering facilities of the German Armed Forces, foodborne outbreaks are commonly attributed to Bacillus cereus, and spores of this organism are regularly found on equipment surfaces. B. cereus is the causative agent of foodborne emetic or diarrheic disease. Hence, the use of sporicidal disinfectants may provide a starting point for successful risk mitigation of diseases associated with B. cereus. In this study, the amphoteric surfactant-based disinfectant (product A) that has been routinely used in catering facilities of the German Armed Forces and a peracetic acid-based disinfectant (product B) were compared for their efficacy against B. cereus spores in laboratory tests and under field conditions. In a carrier test for B. cereus spores, product A displayed no efficacy against spores of the test strain. In contrast, a substantial reduction in spore concentration (>5-log reduction) was achieved with product B. In a controlled trial conducted in seven Army catering facilities, the reduction in the number of B. cereus-positive samples was significantly greater (P < 0.001) for product B (from 28% initial contamination to 3% after application) than for product A (from 33 to 21%). Product B was estimated to be 6.25 times more efficacious than product A. Field trials confirmed the higher efficacy of the peracetic acid-based disinfectant to reduce B. cereus contamination on surfaces as found for the in vitro experiments. The tests used to assess the sporicidal effects of disinfectants were adequate under practice conditions and could be used for sporicidal testing of disinfectants for catering and food production establishments.     

Ozone inactivation of norovirus surrogates on fresh produce

Preharvest contamination of produce by foodborne viruses can occur through a variety of agents, including animal feces/manures, soil, irrigation water, animals, and human handling. Problems of contamination are magnified by potential countrywide distribution. Postharvest processing of produce can involve spraying, washing, or immersion into water with disinfectants; however, disinfectants, including chlorine, have varying effects on viruses and harmful by-products pose a concern. The use of ozone as a disinfectant in produce washes has shown great promise for bacterial pathogens, but limited research exists on its efficacy on viruses. This study compares ozone inactivation of human norovirus surrogates (feline calicivirus [FCV] and murine norovirus [MNV]) on produce (green onions and lettuce) and in sterile water. Green onions and lettuce inoculated with FCV or MNV were treated with ozone (6.25 ppm) for 0.5- to 10-min time intervals. Infectivity was determined by 50% tissue culture infectious dose (TCID(50)) and plaque assay for FCV and MNV, respectively. After 5 min of ozone treatment, >6 log TCID(50)/ml of FCV was inactivated in water and ～2-log TCID(50)/ml on lettuce and green onions. MNV inoculated onto green onions and lettuce showed a >2-log reduction after 1 min of ozone treatment. The food matrix played the largest role in protection against ozone inactivation. These results indicate that ozone is an alternative method to reduce viral contamination on the surface of fresh produce.     

Contribution of wine components to inactivation of food-borne pathogens

ABSTRACT:  Wine is a complex solution containing several components with several likely antimicrobial properties. Low pH (3.0 to 4.0), high organic acid content (titratable acidity ≥6.0 g/L tartaric acid), relatively high ethanol (10% to 15%), and potentially high total sulfur dioxide (0 to 300 ppm) may contribute to inactivation of food-borne pathogens when exposed to wine. The objective was to determine the effect of these 4 parameters on reducing populations of Escherichia coli ( E. coli ) O157:H7 and Staphylococcus aureus . A factorial design was used to test variables (pH, titratable acidity, sulfur dioxide, ethanol) in combinations of low, medium, and high levels. Suspension tests were performed to compare the efficacy of 81 treatments with controlled exposure time of 20 min. Staphylococcus aureus was significantly more resistant to wine treatment than E. coli O157:H7. Stepwise regression analysis of S. aureus inactivation revealed the ordered impact of pH, molecular sulfur dioxide, titratable acidity, and ethanol concentration. Selected analysis of E. coli inactivation revealed the importance of pH and ethanol in predicting inactivation. Total and free sulfur dioxide were not predictive of inactivation of either pathogen. Wine-based solutions may have application as surface disinfectants for food surfaces and food contact equipment. Wine destined to be used as a disinfectant could be enhanced by increasing any of the parameters tested in this study; however, lowering the pH would be the most effective and would likely enhance the efficacy of the other parameters. Additional wine components such as volatile acidity and phenolics were not evaluated but may also contribute to the antimicrobial properties of wine.     

Susceptibility of Vibrio parahaemolyticus to disinfectants after prior exposure to sublethal stress

In the present study, Vibrio parahaemolyticus 690 in phosphate buffered-saline containing 3% NaCl was subjected to sublethal stresses: heat shock at 42 °C for 15 min, acid adaptation at pH 5.0 for 30 min, or cold shock at 20 °C for 4 h. The effect of sublethal stress on the susceptibility of V. parahaemolyticus to a chlorine-containing disinfectant (Clidox-S) and a quaternary ammonium compound (Quatricide) at 25 and 40 °C was investigated. It was found that the sublethal stresses examined enhanced the resistance of V. parahaemolyticus 690 to both disinfectants. Depending on the kinds of sublethal stress, V. parahaemolyticus 690 showed various degrees of enhanced resistance to disinfectants. Furthermore, the phenomenon of enhanced resistance to the disinfectants was more marked at 40 than at 25 °C.