Insight into the Prevalence and Distribution of Microbial Contamination To Evaluate Water Management in the Fresh Produce Processing Industry

Abstract

This study provided insight into the degree of microbial contamination in the processing chain of prepacked (bagged) lettuce in two Belgian fresh-cut produce processing companies. The pathogens Salmonella and Listeria monocytogenes were not detected. Total psychrotrophic aerobic bacterial counts (TPACs) in water samples, fresh produce, and environmental samples suggested that the TPAC is not a good indicator of overall quality and best manufacturing practices during production and processing. Because of the high TPACs in the harvested lettuce crops, the process water becomes quickly contaminated, and subsequent TPACs do not change much throughout the production process of a batch. The hygiene indicator Escherichia coli was used to assess the water management practices in these two companies in relation to food safety. Practices such as insufficient cleaning and disinfection of washing baths, irregular refilling of the produce wash baths with water of good microbial quality, and the use of high product/water ratios resulted in a rapid increase in E. coli in the processing water, with potential transfer to the end product (fresh-cut lettuce). The washing step in the production of fresh-cut lettuce was identified as a potential pathway for dispersion of microorganisms and introduction of E. coli to the end product via cross-contamination. An intervention step to reduce microbial contamination is needed, particularly when no sanitizers are used as is the case in some European Union countries. Thus, from a food safety point of view proper water management (and its validation) is a critical point in the fresh-cut produce processing industry.

Physicochemical Quality and Chemical Safety of Chlorine as a Reconditioning Agent and Wash Water Disinfectant for Fresh-Cut Lettuce Washing

“…However, washing of produce is a potential pathway for spreading contamination among crops (17), and the risk of crosscontamination is not removed by using large quantities of water (18). Chlorine is much more effective for inactivation of bacterial pathogens in wash water than for removal of these pathogens from fresh produce (11,19).…”

Assessment of Food Safety Management Systems in the global fresh produce chain

“…Moreover, across the whole chain workers use water for hand washing, and it can be also applied as an ingredient in processing. Studies have demonstrated and discussed that inadequacies in water control can cause food safety problems in fresh produce (e.g., Holvoet, Jacxsens, Sampers, & Uyttendaele, 2012;Tyrrel et al, 2006). Water control with structured sampling for measuring the contamination risks in relation to the water source (or previous use) and intended use of the water is critical (Steele, Mahdi, & Odumeru, 2005).…”

“…This is valid even when potable water is used, because water quality can deteriorate at all stages through improper storage or cross-contamination (Gerba & Choi, 2006;Gerba, Choi, Sapers, Solomon, & Matthews, 2009). Moreover, sampling information is of high importance for selecting the most effective water treatment technologies (EHEDG, 2007;Holvoet et al, 2012;Pachepsky et al, 2011). Sophisticated water control (advanced level) is typified by water control based on statistically underpinned sampling, and treatment that is tailored and tested for efficacy in the company-specific circumstances.…”

“…Furthermore, the indicators about analytical methods for microbiological hazards and microbiological sampling plan address the microbial analysis conducted in the companies in the chain (Table 2). Studies have stressed the importance of these monitoring issues in fresh produce production, especially postharvest (Blanc, 2006;Holvoet et al, 2012;ICMSF, 1986;Lehto et al, 2011). Typical for advanced levels of the indicators for monitoring systems design is the use of scientific knowledge, which is adapted to own production, systematic and tested (by challenge testing, for example) for the specific food production.…”

“…They are especially important for fresh or minimally processed produce, where full intervention is not possible (da Cruz et al, 2006). An example of this is the washing of vegetables during fresh-cut processing, which is defined as partial intervention in our tool, and is often ineffectively done in practice, because factors influencing its effectiveness are not fully understood by companies and validation is ineffective (Holvoet et al, 2012;Seymour, 1999). The advanced levels are typified by systematic and independent (that is, by external expert) validation, which is based on specific scientific sources, and conducted systematically and after modifications in the FSMS, while the basic levels are validated on an ad-hoc basis, based on historical knowledge, and only judged by internal to the company people (Luning et al, 2009).…”