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Contaminated food contact surfaces play a vital role in spreading Staphylococcus aureus to consumers, resulting in several staphylococcal foodborne outbreaks. This highlights the significance of proper and effective sanitization of food contact surfaces. Although chemical sanitizers are widely used for this purpose, the growing tendency of consumers toward avoiding their uses due to their health hazards in addition to their economic drawbacks shifted our attention to investigating alternative natural compounds. This study aimed to evaluate the efficacy of natural antimicrobial agents, including caprylic acid (CA), lauric arginate ester (LAE), benzyl alcohol (BA), benzyl benzoate (BB), and methyl benzoate (MB), at practical concentrations against S. aureus biofilms on stainless steel surfaces. In general, the antimicrobial efficacies of the investigated sanitizers were enhanced either by increasing their concentrations or by extending the exposure time from 1 to 5 min. The 5-min treatment of 400 ppm CA, 1.0% BA, 1.0% BB, and 1.0% MB reduced the S. aureus biofilm with ∼3.9, 3.4, 2.3, and 2.3 log CFU/coupon, respectively. However, organic matter conditioning of the stainless steel surfaces with diluted whole milk counteracted the antimicrobial efficacies of all the investigated sanitizers. The 5-min treatment of 200 ppm LAE caused ∼2.6 log CFU/coupon reduction of S. aureus biofilm on soiled surfaces, compared to ∼4.4 log CFU/coupon reduction on clean surfaces. The obtained data provide practical information and guidance for effective sanitization of food contact surfaces in the food sector. • Organic matter soiling didn't affect S. aureus biofilm formation on surfaces. • The efficacy of all investigated sanitizers was concentration-dependent. • Increasing exposure time to investigated sanitizers enhanced their efficacy. • The efficacy of investigated sanitizers was reduced by organic matter presence. • LAE (200 ppm, 5-min) reduced 4.4 log S. aureus biofilm on clean surfaces. [ABSTRACT FROM AUTHOR]

Biofilm-forming ability of six two-strain mixtures of fecal coliforms, isolated from six different fresh market blueberry packing lines in Georgia, was assessed at 10 °C for 7 days on coupons made of materials commonly used for fresh market blueberry packing lines, lugs and clamshells. These materials included stainless steel, rubber, polyvinyl chloride, polypropylene, polyurethane, high-density polyethylene and polyethylene terephthalate. Coupons with developed biofilms were treated for 1 min at room temperature with four different sanitizers commonly used by blueberry packers in Georgia, including 5 ppm chlorine dioxide, 3 ppm ozonated water, 200 ppm quaternary ammonium compound or 200 ppm sodium hypochlorite. Residual biofilms on treated coupons were subsequently quantified using the crystal violet binding assay. On average, the amount of biofilm mass was significantly greater (P ≤ 0.05) on polypropylene, compared to the other coupons used in the study. Biofilms formed on polyvinyl chloride and rubber coupons were statisically similar (P > 0.05), but were significantly lower than those on polypropylene and polyurethane coupons and significantly higher than those on high-density polyethylene, stainless steel and polyethylene terephthalate coupons. Ozonated water had significantly higher efficiency in biofilm removal than the quaternary ammonium compound which had significantly higher efficiency than chlorine dioxide, followed by sodium hypochlorite. On average, significantly more residual biofilm mass was found on rubber coupons after the sanitizing treatments. The amounts of residual biofilms on polypropylene, polyvinyl chloride and high-density polyethylene coupons were statistically similar, but were significantly higher than those on polyurethane and stainless steel coupons. The evaluated sanitizers had different efficacies in biofilm removal. The type of coupon materials used in the study played a significant role in biofilm accumulation and removal. These results emphazise the importance of selecting proper chemical sanitizers (with high efficacies in microbial inactivation and biofilm removal) and surface materials (with low tendency in attracting microbial attachments) for fresh market blueberry packing lines because these decisions may affect the hygiene conditions of fresh market blueberry packing lines as well as the microbial quality of the fruits. • Biofilm forming ability of fecal coliforms on several surface coupons was observed. • Efficacy of selected sanitizers in the control of biofilms was evaluated. • Significantly more/less biofilms were formed on polypropylene/stainless steel surface. • Ozonated water was most effective and chlorine was least effective in biofilm removal. • Rubber surface was more difficult and stainless steel surface was relatively easier to clean. [ABSTRACT FROM AUTHOR]

Washing with or without sanitizers is one of the important steps designated to reduce or eliminate microbial hazards in fresh vegetables but the settings, conditions and effectiveness of this step remain contentious. In this study, we investigated kitchen scale salad preparation practices in a field study in Rwandan food service establishments (FSEs) and conducted laboratory trials to identify treatments that can improve reduction of microbial counts during washing and sanitization. In the field study, vegetable samples ( n = 112) were taken from 56 FSEs before and after washing with or without sanitizer(s) to determine reduction of counts of Enterobacteriaceae , Listeria spp., and coagulase positive (CP)-staphylococci coupled with observation of the salad preparation practices from start to end. Based on the results obtained during the field study, 8 sanitizers were evaluated in the laboratory to optimize the efficacy of washing of leafy vegetables (corn salad, Valerianella locusta ). Findings in the field study revealed that about 61% of the visited FSEs used sanitizers during washing of fresh vegetables, in particular, potassium permanganate (KMnO 4 ) in 39% of FSEs, sanitizing powder (a mixture of polyphosphate, sodium hydrogen carbonate and active chlorine), 13%; sodium hypochlorite (NaClO), 7%; and sodium dichloroisocyanurate (NaDCC) in 2%. Average inactivation ranged from 1.0 log (KMnO 4 ) to 3.1 log (NaDCC). In the laboratory study, average inactivation observed with Listeria spp., Escherichia coli and Aerobic plate count (APC) ranged from 0.7 log (water alone) to 3.0 log (NaDCC). Out of the 8 sanitizers that were evaluated, 5 sanitizers (NaDCC [90 ppm], NaClO [200 ppm], lemon juice [98%], acetic acid [2%] and sanitizing powder [4 g/L]) resulted in significantly higher inactivation compared to water alone. A contact time of 5 min and salad-sanitizer ratio of 1: 20 were considered optimal for kitchen based washing of the studied leafy vegetables with NaDCC and NaClO sanitizers. [ABSTRACT FROM AUTHOR]

Microbubbles (MB) technology was applied in a washing process a few studies have been done with food materials, particularly to reduce the microbial contamination on leafy vegetables. This study determined the effectiveness of MB (Ø ∼ 50–70 μm) combined with three sanitizers acidic electrolyte water (AEO, 20 and 40 mg/L, ORP 910–1010 mV, pH 2.7–3.1), chlorine dioxide (ClO 2, 3 and 5 mg/L, ORP 550–680 mV, pH 7.1–7.5), and sodium hypochlorite (NaOCl, 40 and 80 mg/L, ORP 900–990 mV, pH 6.5–6.7) in order to inactivate Escherichia coli and Salmonella Typhimurium on artificially contaminated sweet basil ( Ocimum basilicum Linh) and Thai mint ( Mentha cordifolia Opiz.). Although air MB alone did not possess antimicrobial activity, washing with MB combined with the two oxidizing sanitizers (NaOCl and AEO) for 5 min resulted in an effective reduction in S. Typhimurium and E. coli on sweet basil and Thai mint with 2–3 log reductions (99.2–99.8%). Washing vegetables with MB and NaOCl at a concentration of free chlorine of 40 mg/L NaOCl or 20 mg/L AEO yielded the best results in killing S. Typhimurium with 1.21–1.90 and 0.67–2.25 log reductions, respectively. In addition, the reduction of E. coli and S. Typhimurium on sweet basil appeared to be higher than on Thai mint. Differences in surface roughness may assist the bubbles and sanitizers to detach bacterial cells and therefore increase the washing efficacy. Furthermore, applying sanitizers in washing solution was a powerful means of killing planktonic E. coli and S . Typhimurium in the wash water and preventing cross-contamination in the washing process. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate the efficacy of tap water (TW), commercial electrolyzed water (EW), and a commercial acid-based sanitizer (AS) in preventing cross-contamination of cantaloupe during processing in retail settings. A whole cantaloupe was dip-inoculated with a cocktail of Salmonella or L. monocytogenes to achieve approximately 5 log CFU/cm 2 . One inoculated and two non-inoculated whole cantaloupes were treated in 76 L of TW, EW (free chlorine: 50–60 ppm), or AS (pH 2.8, combination of lactic acid and phosphoric acid) for 5 min. Subsequently, fresh-cut cantaloupe flesh from the inoculated and non-inoculated cantaloupes were soaked together in 76 L of TW, EW, or AS for 90 s. EW treatment resulted in an approximately 1.5 log reduction in both Salmonella and L. monocytogenes on the rind of whole cantaloupe, which was significantly greater than with the TW treatment (0.5 log reduction) ( P < 0.05). Cross-contamination of non-inoculated whole cantaloupes occurred when washed with inoculated whole cantaloupe in TW (four of four cantaloupes positive for Salmonella and L. monocytogenes ) or AS (four of four cantaloupes positive for Salmonella and two of four positive for L. monocytogenes ). Cross-contamination did not occur when whole cantaloupes were washed in EW. Additional washing of mixed fresh-cut cantaloupe flesh from the inoculated and non-inoculated cantaloupes prepared after washing of whole cantaloupes demonstrated that the EW treatment reduced the likelihood of cross-contamination compared with TW and AS. No viable Salmonella or L. monocytogenes were detected from 100 mL sample of EW processing water, but were detected in TW and AS ( L. monocytogenes only). The addition of a sanitizing agent to water used for the processing of whole and fresh-cut cantaloupe in a retail setting is recommended to prevent cross-contamination and reduce microbial load. [ABSTRACT FROM AUTHOR]

This study evaluated the Pulsed Light technology (PL) for its efficiency to reduce the microbial loads on mung bean sprouts and endive salad during a simulated wash process for up to 60 s. The microbicidal action of PL proved to be more efficient than the sanitizers electrolyzed water (40 ppm free chlorine) and chlorine dioxide (15 ppm) within the same treatment time. Reductions of the microbial count up to 2.5 log were found in case of PL treated endive salad while both sanitizers only caused maximum reductions by about 1.5 log. A combination of PL and sanitizers did not have pronounced additional effect for both endive salad and mung bean sprouts. Overall, the decontamination treatments were more effective in case of endive salad compared to mung bean sprouts. It was also shown that the microbial loads in the washing water may be kept on a low level during PL treatments as count reductions of approx. 3 log were found in relation to simply washing in tap water. This study reveals that PL may be a suitable approach to reduce microbial hazards of industrially manufactured fresh produce. The application during the washing process not only reduces microbial loads on the product surface but also efficiently inactivates suspended microorganisms in the wash water and may therefore be an alternative to sanitizers for the prevention of cross contaminations. [ABSTRACT FROM AUTHOR]

Food processing lines, especially in dairies, offer various microenvironments in which multiple microorganisms can multiply and form biofilms. Thus, efficient industrial procedures, such as the clean-in-place (CIP) process, are essential, as well as optimizing the use of economic and environmental resources associated with the hygiene process. In this context, the objective of this study was to evaluate the adhesion and biofilm formation of Bacillus cereus , investigate the efficiency of the conventional CIP process applied to dairy products, and propose an alternative form of the process with the pulsed flow in the sanitization. For this purpose, a stainless steel AISI 304 milk circulation line with different geometries (straight section, tee, elbow, expansion, and reduction) was used. Hygiene monitoring was done based on viable cell counts and logarithmic decimal reduction of the count. The experimental scenario was designed with rotational central composite planning as a function of sanitizing solution concentration and circulation time. Finally, the response surface evaluated the influence of the variables under study, and the desirability analysis determined the best CIP operating conditions for all geometries. The tee geometry was the most challenging due to stagnation zones and fluid recirculation, which reduce flow velocity. The variables studied were statistically significant in the decimal reduction of B. cereus adhered to the surfaces. The optimization reduced downtime by around 20% compared to the conventional process and minimized energy consumption by 14% and sanitizing agent by 25%. Furthermore, it was able to produce statistically equal decimal reductions in the elbow (∼4.1 log CFU∙cm−2), expansion (∼4.4 log CFU∙cm−2) and reduction (∼4.6 log CFU∙cm−2), and when compared to conventional CIP, it increased the decimal reduction by 0.45 log CFU∙cm−2 in the straight cylindrical section and by 2.3 log CFU∙cm−2 in the tee branch. The configuration proposed in the present study optimized the CIP process, resulting in an increased decimal reduction of Bacillus cereus even in the most challenging geometry under study. • CIP and pulsed flow was effective to optimize the conventional process. • CIP produced decimal reductions in the elbow, expansion and reduction geometries. • CIP increased the decimal reduction in the straight section geometry. • The line design can result in microbial adhesion and growth. [ABSTRACT FROM AUTHOR]

Chlorine remains the most popular method used by the fresh produce industry for decontamination. However, the occurrence of disinfection by-products (DBP) derived from chlorine-based disinfectants has been highlighted as a problem. After recent reports, chlorate residues in fresh produce are of concern in Europe. This study evaluated the chlorate accumulation in process wash water and the residues in fresh-cut lettuce when sodium hypochlorite was used as a wash aid. At a commercial processing facility, total chlorine was continually added to achieve a free chlorine level of 1–80 mg L −1 for water disinfection as the organic load measured as chemical oxygen demand (COD) increased over time (1000–1500 mg O 2 L −1 ). This resulted in chlorate accumulation (19–45 mg L −1 ) in the process water. When fresh-cut lettuce was washed in that water, chlorate residues were detected in the lettuce and the concentrations increased linearly with the repeated use of the same process water, reaching concentrations of 4.5–5.0 mg kg −1 . To understand the chlorate accumulation in the process wash water, several experiments were performed at a pilot plant scale with different levels of COD and free chlorine. There was a significant (p < 0.001) correlation (R = 0.91) between the total added chlorine and the chlorate accumulation in the process water. We demonstrated that the added chlorine needed to maintain a free chlorine level in the process water was the contributing factor to chlorate accumulation. Chlorate residues in the washed fresh-cut lettuce after rinsing for 1 min in tap water and in commercial bags were below the limit of quantification. This study contributes to the knowledge of chlorate accumulation in the process water when sodium hypochlorite was used as a sanitizer. [ABSTRACT FROM AUTHOR]

Consumption of vegetables is increasing due to demand for healthy products in peoples' diets. To reduce microbial contamination and maintain freshness, industrial processes in Portugal rely on minimally processing of vegetables with hypochlorite as sanitizer. Formation of toxic chlorine derivatives has raised concern restrictions to its use and alternatives with whey permeate as a disinfection agent has been attempted. The aim of this work was to evaluate the bio potential of fermented cheese whey, for use on disinfection of minimally processed lettuce organically grown. Assays were made with whey obtained from inoculated milk during cheese processing, fermented for 120 h at 37 °C, after which, among other carbohydrates, lactic acid was measured by HPLC, giving average yields of 18 g L −1 . The sanitizing effect of whey, undiluted, 75 and 50% solutions, was compared with 110 ppm sodium hypochlorite, after rinsing. Aerobic Microorganisms (AM), Psychrotrophic Microorganisms (PM) and Enterobacteriaceae (ENT), were used as indicators for hygiene quality. For a level of significance of P < 0.05, the hygiene quality standards of lettuce samples, were better using 75% whey solution (AM 6.62, PM 7.48 cfu g −1 ), than using sodium hypochlorite (AM 7.48, PM 8.15 cfu g −1 ), for the 7 days of shelf life studied. Evaluation of Enterobacteriaceae showed significant differences after 3 days, between water (ENT 4.98 cfu g −1 ) sodium hypochlorite (ENT 4.81 cfu g −1 ) and 75% solution of whey (ENT 4.63 cfu g −1 ). Considering the actual limitations imposed to chlorine sanitation, these results point a good alternative to the food industry, especially for organic fresh vegetables, which are chemical free brands. [ABSTRACT FROM AUTHOR]

Abstract: Electrochemically activated water (ECAW), also known as electrolyzed water, and ozonized water are typically effective in inactivating bacteria, but their generation typically uses high current and voltage. A few simpler antimicrobial technologies that are also based on the application of a mild electrical current have been recently marketed to food retail and service customers claiming to have sanitizing properties for controlling bacteria. The objective of this study was to determine the sanitizing effect of some of these commercial technologies on Escherichia coli O157:H7, Listeria monocytogenes, and Salmonella enterica and compare them with sterile water, generated ECAW generated with a pilot size electrolyzing unit, and salt solutions sprayed using commercial device sprays. A concentration of 100 mg/L ECAW had sanitizing effects of at least 5 log CFU/mL reductions on liquid culture and more than 4 log CFU/coupon reductions for E. coli O157:H7, L. monocytogenes and Salmonella dried on stainless steel surface, respectively. No bacterial cells were detected by direct plate counting post-ECAW treatment. In contrast, the treatment of liquid cultures with any of the commercial technologies tested resulted in non-significant bacterial cell reductions greater than 0.5 log CFU/mL. Similarly, when cells had been dried on metal surfaces and treated with any of the water generated with those technologies, no reductions were observed. When the manufacturer's instructions were followed, the reduction of cells on surface was largely due to the physical removal by cloth-wiping after water fraction application. These results indicate that treatment with any of these portable technologies had no noticeable antimicrobial activity. These results would be helpful for guiding consumers when choosing a right sanitization to ensure food safety. [Copyright &y& Elsevier]

Abstract: The effects of hardness and pH of water used to prepare electrolyzed oxidizing (EO) water and bleach solutions on the bactericidal activity of sanitizer prepared from the water were examined. EO water and bleach solutions were prepared with hard water of 0, 50, 100, and 200 mg/l as CaCO3 at pH 5, 6, 7, and 8. Increased water hardness tended to increase free chlorine and oxidation–reduction potential (ORP) and decrease pH of EO water. Chlorine levels also increased with water pH. Water hardness and pH only had minor effect on the pH of bleach solutions. Increasing hardness to 50 mg/l increased antimicrobial effect of EO water against Escherichia coli O157:H7, but reduced when water hardness further increased to 100 mg/l or higher. Water pH had no effect on EO water produced against E. coli O157:H7. Water hardness had no significant effect on bactericidal activity of EO water against Listeria monocytogenes but elevated water pH decreased bactericidal activity of EO water produced against L. monocytogenes. Bleach solution prepared using hard water at 200 mg/l or at pH 7 or higher had significant lower efficacy in inactivating E. coli O157:H7, but had no effect on the inactivation of L. monocytogenes. Results indicate that increasing the hardness or pH of water used to prepare EO water or bleach solutions will decrease the bactericidal activity of sanitizers prepared from the water. [Copyright &y& Elsevier]

Abstract: The objective of this study was to determine the efficacy of novel home-use sanitizers (ozonated water, FIT solution, and EO water) in killing Escherichia coli O157:H7 on blueberries compared to common bleach solution and tap water. Blueberries samples (6 berries; ca. 10 ± 1 g) were spot-inoculated with 60 μl (10 μl/berry) of a mixture of 5 strains E. coli O157:H7 (ca. 8–9 log CFU/ml) and treated in sanitizers for 1–5 min. The greatest reductions of the pathogen (4.4–4.8 log CFU/g) were achieved by treating blueberries in bleach solutions (100 mg/l free chlorine), followed by EO water (30 mg/l free chlorine; 3.9–4.4 log CFU/g), FIT solution (3.3–4.6 log CFU/g), ozonated water (1.5 mg/l ozone; 2.3–3.5 log CFU/g), and tap water (1.9–2.7 log CFU/g). In general, increasing treatment time from 1 to 5 min significantly increased the reduction of the pathogen, except for the bleach solution. In most cases, FIT solution, EO water, and bleach solution inactivated E. coli O157:H7 in treatment solutions after use. Application of novel sanitizers to wash blueberries at home and food services could reduce the risk of E. coli O157:H7 that may attach to the berries and minimize cross-contamination during preparation of foods. [Copyright &y& Elsevier]

Abstract: This study evaluated the microbiological quality of 180 lettuce samples (Lactuca sativa) of the iceberg variety from different cropping systems and examined the efficacy of two sanitizers in reducing the bacterial counts. The results showed high contamination by mesophilic aerobic bacteria in traditionally grown and organically grown samples, which also possessed thermotolerant coliforms above the recommended levels in 66% and 80% of samples, respectively. Salmonella sp. was not detected in any of the analyzed samples. Traditionally grown and organically grown samples also exhibited a high frequency of intestinal parasites, including the pathogenic Taenia sp. and the Entamoeba histolytica species. In contrast, only 20% of hydroponically grown lettuce samples were contaminated with parasites. Sodium hypochlorite and acetic acid at concentrations of 100 mg L−1 and 1%, respectively, were effective in reducing bacterial counts, even in samples with high levels of contamination. [Copyright &y& Elsevier]

Abstract: Listeria monocytogenes is the causative agent of listeriosis in humans. Its wide distribution in the environment is one of the main reasons it is a source of food poisoning. L. monocytogenes also forms biofilms, making cleaning and sanitation difficult. Microtiter plate assays have previously been used to assess biofilm formation of L. monocytogenes and to evaluate the antimicrobial activity of disinfectants in suspension. In this study, we have used a microplate assay to evaluate the minimum sanitizer concentrations required for a 5 log10 CFU/ml decrease of L. monocytogenes cells in suspension and in biofilm. Twenty-one sanitizers were tested against 20 strains of L. monocytogenes. The results showed that all tested sanitizers achieved a 5-log10 reduction of viable cells in suspension at concentrations below the manufacturers'' recommended concentrations, of a biguanide-based product. When tested against L. monocytogenes in biofilm, only the peroxyacetic acid, chlorine dioxide and acidified sodium chorite-based products gave a 5-log10 decrease, within or close to the manufacturers'' recommended concentrations. No relationship was observed between susceptibility to chemical sanitizers and other characteristics of the isolates: pulsotypes, sources, biofilm forming ability or persistence. This work suggests that caution must be taken in selecting an appropriate sanitizer for use in food processing plants and an effective cleansing programme is required to ensure thorough inactivation and removal of L. monocytogenes in biofilms. [Copyright &y& Elsevier]

Abstract: This study aimed to assess the adhesion, detachment kinetic and biofilm formation of Staphylococcus aureus isolates from food services surfaces on stainless steel and polypropylene surfaces when cultivated in a vegetable-based broth at 7 and 28 °C, and the efficacy of peracetic acid (30 mg/L) and sodium hypochlorite (250 mg/L) in removing the bacterial cells from the matrix of the preformed biofilm. The isolates adhered over 4 Log cfu/cm2 regardless the surface kind and incubation temperature. Cell detachment was around 3 Log cfu/cm2 over the first six contacts with agar characterizing a high persistence of cells on the tested surfaces. Number of cells (5–7 Log cfu/cm2) needed for biofilm formation was noted at all experimental systems already after 3 days of incubation. A range of 2.0–3.3 and 1.5 to 2.1 Log cfu/cm2 was observed in the reduction of cells in biofilm matrix caused by peracetic acid and sodium hypochlorite, respectively. The isolates of S. aureus revealed high capability to adhere and form biofilm on the tested surfaces in both assayed incubation temperature. [Copyright &y& Elsevier]

Abstract: Washing procedures applied to fresh produce have the potential to reduce contamination from the surface of the product. However, the wash water may also serve as a source of contamination or has great potential to result in cross-contamination. The objective of this study was to evaluate process handling cross-contamination potential and pathogen removal of initially low numbers of attached cells of Salmonella and Escherichia coli O157:H7 during the washing-disinfection, rinsing, and de-watering steps of fresh-cut Red Chard baby leaves as affected by NaClO and ClO2. The efficacy and stability of liquid ClO2 applied to the water as the disinfectant treatment was also evaluated. Non-inoculated leaves were mixed with inoculated leaves (about 3–5% of total weight) and processed as a unit. After processing, no confirmed colonies on selective media were recovered from the non-inoculated leaves and qPCR was used for detection below the limit of quantitative recovery. ClO2 substantially prevented E. coli O157:H7 cross-contamination but was not effective for the inoculated Salmonella. Large populations of Salmonella were recovered from centrifugation discharge effluent water whereas no colonies were detected from water in contact with inoculated leaves collected from preceding washing unit operations. At an industrial level, this represents a potential risk of cross-contamination to product and equipment at the step immediately prior to packaging. These results suggest that the centrifugation effluent water could be used as a potential sample point to evaluate lot contamination and cross-contamination in the processing chain, even at low levels of pathogens, as were used in this study, undetectable by conventional sampling methods. [Copyright &y& Elsevier]

Abstract: The minimal inhibitory concentrations (MICs) and the minimal bactericidal concentrations (MBCs) of five sanitizers (alkyl amine acetate, phosphoric acid, anionic tension active and two chlorine/alkaline) against 15 isolates of Listeria monocytogenes (including isolates found persistently in two dairies) were determined. Alkyl amine acetate was the only agent whose efficacy was poorly affected by the presence of organic matter. The values of MICs and MBCs of cells pre-exposed to sub-inhibitory and sub-lethal concentrations of the disinfectants, did not suggest adaptation. It is possible that factors other than resistance or adaptation to sanitizers could account for the persistence of particular clones of L. monocytogenes in these dairies. [Copyright &y& Elsevier]

The presence of enteric viruses on fresh berries poses a health risk to consumers. After berries are picked, a washing step can reduce microbial counts on fruit surfaces to increase their safety. This study compared the effectiveness of tap water, commercial solutions of fruit and vegetable sanitizer composed of peroxyacetic acid and hydrogen peroxide (PAA) and neutral electrolyzed oxidizing water (NEW) for washing fresh blueberries that had been inoculated with either murine norovirus (MNV-1), bacteriophage MS2, bovine rotavirus (boRV) or hepatitis A virus (HAV). Initially, inactivation levels were measured after blueberries were washed for 1, 3, 5, 10 and 20 min. Subsequently, the effect of combining up to three sequential 1-min washes was evaluated. Washes with water lasting up to 20 min reduced MNV-1, MS2 and HAV populations by 1–2 log 10 (PFU) and boRV by less than 4 log 10. Increasing washing time did not have a significant effect, except where NEW washes were increased by up to 3 min for MS2 and by 10 min for boRV, with viral titers decreasing by > 4 log 10 and >5 log 10 , respectively. Viral counts were further reduced through additional washes as follows: reduction of MS2 with water, of MNV-1 with NEW and HAV with PAA. PAA achieved significant and rapid inactivation of boRV (>6 log 10 PFU after 1 min), MNV-1 (>4 log 10 after 10 min) and MS2 (>3 log 10 after 3 min). HAV was moderately affected (<3 log 10 after 20 min or 3 log 10 after 3 washes). NEW was effective at inactivating MNV-1 (>4 log 10 after 1 min), MS2 (>4 log 10 after 3 min) and HAV (>4 log 10 after 1 min). For boRV, washing time needed to be increased to 10 min or three sequential washes were needed to reach >5 log 10 reduction. These results highlight the efficiency of PAA at reducing infectivity of MNV-1, MS2 bacteriophage and boRV, and NEW to inactivate the four viruses. • Water washes were the least effective at reducing viral infectivity of MNV-1, MS2, boRV and HAV. • Highest reduction of boRV infectivity was obtained using a solution of peracetic acid and hydrogen peroxide (PAA). • Highest reduction of HAV infectivity was obtained using neutral electrolyzed water (NEW). • NEW and PAA reduced MNV-1 and MS2 infectivity efficiently. • NEW was efficient in reducing infectivity of MNV-1, MS2, HAV and boRV. [ABSTRACT FROM AUTHOR]