Horticultural assessment scheme: insight in prevalence and distribution of microbial contamination to evaluate water management in fresh produce processing industry

Title: Horticultural Assessment Scheme: insight in prevalence and distribution of microbial contamination to evaluate water management in fresh produce processing industry. Introduction: Microbial food safety is a global concern. Particularly, fresh produce is increasingly involved in some outbreaks. Many food borne illnesses are related with contamination during the postharvest processing (e.g. washing, chilling). The source and contamination level of the used water is an important issue that influences the degree of contamination at all stages in the chain. Purpose: The purpose is to present the concept of a ‘Horticultural Assessment Scheme’ as systematic approach in sampling and analysis in order to obtain a helicopter view on microbial quality, hygiene and safety level of products and processes in a company. It may help to identify bottlenecks in management of food safety and water. Methods: A Horticultural Assessment Scheme (HAS) is developed to assess the level of microbiological quality of leafy vegetables during postharvest processing. HAS is a procedure that defines the identification of critical sampling locations, the selection of microbiological parameters, the assessment of sampling frequency, the selection of sampling method and method of analysis, and finally data processing and interpretation. Results: The results of the HAS showed that (a) neither Salmonella nor L. monocytogenes were detected in the frame of this sampling plan. It turned out that the (b) total psychrotrophic aerobic count is perceived to be, neither for the fresh produce samples nor for the water or environmental samples, a good indicator of overall microbial quality and good practices during production and processing. And (c) if there is a lack of refilling the water and high product/water ratio’s, a fast build up of E. coli and transfer to the end product occurs. Significance: The results obtained by analysis of hygiene indicator E. coli along with the information obtained on the ratio of the product/water used in the washing baths and frequency of refilling water enabled to evaluate water management in these two companies involved in production of pre-packed cut fresh produce. The companies need to validate their water management and optimize the process to guarantee a proper water quality from the start until the end of the process. However, the difficulty about a proper water management is the lack of guidelines on acceptable microbial contamination in wash water, product/volume ratio and frequency of refilling fresh water to washing baths

The use of essential oils in marinade to extend the microbial shelf life of fish and meat

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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

The use of redox potential to estimate free chlorine in fresh produce washing operations : possibilities and limitations

Maintaining free chlorine (FC) residual at appropriate pH values is a control approach used to prevent pathogen cross-contamination during tomato dump tank handling and fresh-cut produce washing operations. Oxidation reduction potential (ORP) is a rapid measurement of oxidant-based sanitizer strength, and has been used to estimate FC residual. However, factors, in addition to FC and pH, which influence ORP are not fully understood. This study examined the relationship between ORP and FC under chlorine demand (CLD) free conditions and during fresh produce washing. An equation predictive of FC was developed in the form logFC = f(ORP, ORP2, ORP.pH). A good correlation between ORP and logFC was maintained when other variables changed, but the resulting ORP-logFC curve changed (slope, intercept). A decrease in pH or temperature led to an increase in ORP. Using tap water to wash the produce instead of distilled water significantly changed the ORP. For different types of tested produce, i.e., fresh-cut carrot, onion, romaine and iceberg lettuce, and for whole tomatoes, increasing the product-to-water ratio (i.e., increasing the organics transferred into the water) led to a decrease in ORP for a specific FC residual. The choice of acidulant during washing also influenced ORP. Overall, the correlation of ORP with logFC is more reliable at the lower end (5 mg/L FC) than at the higher end (100 mg/L FC) of the FC range used in fresh produce washing. However, since the ORP in fresh produce wash water is affected significantly in multiple ways by the wash water and process conditions, the predicted FC values with ORP under certain fresh-cut produce washing conditions cannot be generalized for other conditions