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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.

Kluai Khai (Musa AA Group) and Kluai Hom Thong (Musa AAA Group) bananas were stored at 6 and 10 °C. Visible chilling injury (CI) in the peel, mainly browning, occurred at both temperatures, but more so at 6 °C, and without significant differences between the cultivars. At the time of harvest, total free phenolics in the peel were three times lower in Kluai Khai than in Kluai Hom Thong fruit, the polyphenol oxidase (PPO) activity in Kluai Khai being considerably higher and phenylalanine ammonia lyase (PAL) activity much lower. As CI developed, PAL and PPO activities in the peel increased, and total free phenolics decreased. The decrease in total free phenolic compounds and the increase in PAL and PPO activities occurred more rapidly at 6 °C than at 10 °C, in both banana cultivars. Correlations between visible CI and the level of total free phenolics, and between CI and the activities of PPO and PAL, were all highly significant. The results indicate that low temperature stress induced concerted activities of PAL and PPO, which resulted in browning. Since the concentrations of free phenolic compounds and the rate of PAL and PPO activities varied considerably between the two cultivars, but browning did not, the changes in the biochemical parameters rather than their absolute levels were correlated with peel browning.

A screening in a sugar snap packaging company showed a converged build-up of aerobic psychrotrophic plate count (APC) (ca. 6.5 log CFU/100mL), yeasts and molds (Y&M), and lactic acid bacteria (LAB) (both ca. 4.5 log CFU/100mL) in the wash water in the absence of water sanitizer, and a low build-up of chemical oxygen demand (30 ± 5 mg O2/L) and turbidity (5.2 ± 1.1 NTU). Decontamination experiments were performed in the lab with Purac FCC 80® (80% L(+) lactic acid), two other commercial water sanitizers based on organic acids (NATRApHASe-ABAV®, and NATRApHASe-FVS®) and chlorine to evaluate their performance in reduction of the sugar snap microbial load as well as their functionality as disinfectant of the wash water to avoid cross-contamination. An additional 1 log reduction of APC on the sugar snaps was achieved with lactic acid in the range 0.8 to 1.6%, ABAV 0.5%, and free chlorine 200mg/L when compared to a water wash, while no significant difference in the numbers of Y&M was obtained when washing in sanitizer compared to water. There was no significant influence of the studied concentration and contact time on decontamination efficiency. Treatment with lactic acid 0.8% resulted in a lower APC contamination on the sugar snaps than on the untreated and water washed samples for 10 days. Chlorine 200mg/L was the only treatment able to maintain the Y&M load lower than the untreated samples throughout the entire storage duration. The use of water sanitizers could not extend the sensorial shelf-life. Microbial loads were not indicative/predictive of visual microbial spoilage (shelf-life limiting factor), whereas maturity and amount of damage at the calyx end of the pods were. The APC wash water contamination (5.2 log CFU/100mL) was reduced significantly by chlorine 20 to 200mg/L (to 1.4 log CFU/100mL), ABAV 0.5 to 1.5% (to 2.7 log CFU/100mL), FVS 0.5% (to 2.7 log CFU/100mL) and lactic acid 0.8 to 1.6% (to 3.4 log CFU/100mL). Only the use of chlorine enabled the reduction of the Y&M wash water contamination significantly (from 3.4 to 1.4 log CFU/100mL). The low physicochemical build-up of the sugar snap wash water during the industrial washing process makes free chlorine attractive as a water disinfectant to prevent bacterial and fungal cross-contamination, whereas the sanitizers based on organic acids are not, due to their weak water disinfection efficiency.

Foodborne outbreaks appear to increase with more incidences linked to fresh produce and derived food products. This indicates inadequacies in Food Safety Management Systems (FSMSs), which are currently implemented in companies along the fresh produce chain. However, the information related to these inadequacies is restricted and little is known about the status of the FSMS. This paper describes the development of a tool for assessment of FSMS implemented in the fresh produce chain. The tool consists of indicators and grids to assess activities that are important for fresh produce, and the system output in terms of microbiological and chemical food safety (that is, pesticide residues and emerging mycotoxins). Three sets of indicators, one for each stage of the production chain (primary production, processing and trade), have been validated by experts and tested in companies. The tool enables an integral and comprehensive assessment of FSMS across the entire supply chain. Users of the tool can identify improvement opportunities and learn how to develop towards more advanced levels of activities. For research purposes differences in FSMS can be identified and linked to type of commodity, production system, country, etc.

Shelf-life of minimally processed vegetables (and fruits) is limited because peeling, cutting, mincing, and other preparatory operatins cause cell damage and the release of compounds that mutually interact. Apart from that, such a product is more susceptible to microorganisms from the air or from the objects that it might get in contact with. The aim of this study was to investigate the quality changes in vacuum packed cut Iceberg lettuce (Igloo variety) treated with propionic or ascorbic acid during a 10-day storage at 4oC. The cut lettuce was rinsed with cold water, centrifuged at 920 rpm during 2 min and dipped in 1 % of ascorbic acid or in 0.1 % of propionic acid solutions for 20 s. The residual surface water was removed by centrifugatin. About 300 g of product was packed in the polypropylene (PP) bags of 60 um film thickness, which were evacuated to a pressure of 60 mm Hg and sealed. After each period of storage two replicates were tested for dry matter, total acidity, polyphenoloxidase (PPO) activity, total ascorbic acid content (TTA), total colour, overall visual quality (all at day 0, 3, 6 and 10), microbial load (all at days 0, 6 and 10) and volatile compounds (at day 7). The results have shown that treatment with 1 % of ascorbic acid solution after cutting may successfully prevent PPO activity and enzymatic browning of the minimally processed Igloo lettuce if it is vacuum packed into PP bags and stored for 7-8 days at 4oC. The treatment with ascorbic acid caused, at the very beginning, a slight loss of green colour intensity (the decline of colour L value and -a value), but better colour stability, better overall visual quality scores for appearance as well as less PPO activity during storage, compared to the samples treated with propionic acid and untreated samples. The treatments with ascorbic acid solution prevented the production of acetaldehyde, ethylacetate and ethanol and some other volatile compounds.