Methodology for modeling the disinfection efficiency of fresh-cut leafy vegetables wash water applied on peracetic acid combined with lactic acid

A methodology to i) assess the feasibility of water disinfection in fresh-cut leafy greens wash water and ii) to compare the disinfectant efficiency of water disinfectants was defined and applied for a combination of peracetic acid (PAA) and lactic acid (LA) and comparison with free chlorine was made. Standardized process water, a watery suspension of iceberg lettuce, was used for the experiments. First, the combination of PAA + LA was evaluated for water recycling. In this case disinfectant was added to standardized process water inoculated with Escherichia coli (E. coli) O157 (6 log CFU/mL). Regression models were constructed based on the batch inactivation data and validated in industrial process water obtained from fresh-cut leafy green processing plants. The UV254(F) was the best indicator for PAA decay and as such for the E. coli O157 inactivation with PAA + LA. The disinfection efficiency of PAA + LA increased with decreasing pH. Furthermore, PAA + LA efficacy was assessed as a process water disinfectant to be used within the washing tank, using a dynamic washing process with continuous influx of E. coli O157 and organic matter in the washing tank. The process water contamination in the dynamic process was adequately estimated by the developed model that assumed that knowledge of the disinfectant residual was sufficient to estimate the microbial contamination, regardless the physicochemical load. Based on the obtained results, PAA + LA seems to be better suited than chlorine for disinfecting process wash water with a high organic load but a higher disinfectant residual is necessary due to the slower E. coli O157 inactivation kinetics when compared to chlorine.Ciencias de la Alimentació

A Bayesian modelling framework to estimate Campylobacter prevalence and culture methods sensitivity: application to a chicken meat survey in Belgium

AIMS: To estimate the true prevalence of Campylobacter and the diagnostic sensitivity of routine detection methods by applying a Bayesian modelling approach. METHODS AND RESULTS: Results from a Belgium-wide survey of Campylobacter contamination in chicken meat preparations (n = 656 samples) showed that Campylobacter was detected in 24.2% of the samples by enrichment, compared with 41% detected by direct plating. Combining positive results from both methods increased the apparent prevalence to 48.02%. Bayesian model was set up in WinBUGS software, the model estimates Campylobacter prevalence as 60% (95% Credibility interval (CI): 47-82%), and the sensitivity of enrichment culture and direct plating as 41% (95% CI: 31-52%) and 69% (95% CI: 50-85%), respectively. CONCLUSIONS: The parallel use of direct plating and enrichment culture adds value for Campylobacter detection from chicken meat preparations, but the false-negative results from each culture method must be taken into account. SIGNIFICANCE AND IMPACT OF THE STUDY: Monitoring data could be strongly biased by the microbiological techniques used to generate it. To circumvent this bias, we describe an applied Bayesian framework for better interpretation of Campylobacter survey data in view of the imperfect test characteristics of routine culture methods

Semi-quantitative study to evaluate the performance of a HACCP-based food safety management system in Japanese milk processing plants

This study aimed to gain an insight in the performance of Hazard Analysis and Critical Control Points (HACCP)-based food safety management systems (FSMS) implemented in Japanese milk processing plants. Since 1995, Japan has a comprehensive approval system for food manufacturing establishments by evaluating the development and implementation of GHP and HACCP by the food manufacturing companies/operators. An FSMS-diagnostic instrument was applied to assess the level of the core control and assurance activities in the FSMS and to judge the risk level of the context wherein the companies operate. The data were collected in 13 dairy companies (mostly located around Tokyo area) and involved in-depth interviews performed (by the National Institute of Public Health) with responsible quality assurance persons of respective companies. The results revealed that the microbial food safety output was higher for companies with national HACCP approval. They have more advanced FSMS in combination with a less risky context. All Japanese companies scored high on technology-dependent activities (i.e. preventive measures and intervention processes), but less in managerial activities as monitoring and typical quality assurance activities as validation and verification of the FSMS. Japan has a detailed vertical legislation, leading to a “hazard-based” and ”legislation-based” FSMS compared to a “science- or risk-based” FSMS common in Europe

Processing practices contributing to Campylobacter contamination in Belgian chicken meat preparations

The aim of this study was to obtain insight into processing practices in the poultry sector contributing to the variability in Campylobacter contamination in Belgian chicken meat preparations. This was achieved by company profiling of eleven food business operators, in order to evaluate variation of processing management, in addition to statistical modelling of microbiological testing results for Campylobacter spp. contamination in 656 end product samples. Almost half (48%) of chicken meat preparation samples were positive for Campylobacter spp. Results revealed a statistically significant variation in Campylobacter contamination between 11 chicken meat producers across Belgium at both quantitative and qualitative detection levels. All producers provided Campylobacter-positive samples, but prevalence ranged from 9% up to 85% at single producer level. The presence or addition of skin during production of chicken meat preparations resulted in almost 2.2-fold increase in the probability of a sample being positive for Campylobacter, while chicken meat preparations made from frozen meat, or partly containing pre-frozen meat, had a significant (Odds Ratio=0.41; CI 95% 0.18:0.98) lower probability of being positive for Campylobacter. However, the quantitative results indicated that the positive freezing effect on Campylobacter count was compromised by the presence and/or adding of skin

Effect of Disinfectants on Preventing the Cross-Contamination of Pathogens in Fresh Produce Washing Water

The potential cross-contamination of pathogens between clean and contaminated produce in the washing tank is highly dependent on the water quality. Process wash water disinfectants are applied to maintain the water quality during processing. The review examines the efficacy of process wash water disinfectants during produce processing with the aim to prevent cross-contamination of pathogens. Process wash water disinfection requires short contact times so microorganisms are rapidly inactivated. Free chlorine, chlorine dioxide, ozone, and peracetic acid were considered suitable disinfectants. A disinfectant’s reactivity with the organic matter will determine the disinfectant residual, which is of paramount importance for microbial inactivation and should be monitored in situ. Furthermore, the chemical and worker safety, and the legislative framework will determine the suitability of a disinfection technique. Current research often focuses on produce decontamination and to a lesser extent on preventing cross-contamination. Further research on a sanitizer’s efficacy in the washing water is recommended at the laboratory scale, in particular with experimental designs reflecting industrial conditions. Validation on the industrial scale is warranted to better understand the overall effects of a sanitizer