Pothakos Vasileios, Snauwaert Cindy, De Vos Paul, Huys Geert, Devlieghere Frank
LFMFP, Laboratory of Food Microbiology and Food Preservation, Department of Food Safety and Food Quality, Faculty of Bioscience Engineering, Ghent University, Member of Food2Know, Coupure Links 653, Gent B-9000, Belgium.
BCCM/LMG Bacteria Collection, Faculty of Sciences, Ghent University, K. L. Ledeganckstraat 35, Gent B-9000, Belgium.
Int J Food Microbiol. 2014 Aug 18;185:7-16. doi: 10.1016/j.ijfoodmicro.2014.05.009. Epub 2014 May 15.
A study monitoring lactic acid bacteria contamination was conducted in a company producing fresh, minimally processed, packaged and ready-to-eat (RTE) vegetable salads (stored at 4°C) in order to investigate the reason for high psychrotrophic LAB levels in the products at the end of shelf-life. Initially, high microbial counts exceeding the established psychrotrophic thresholds (>10(7)-10(8)CFU/g) and spoilage manifestations before the end of the shelf-life (7days) occurred in products containing an assortment of sliced and diced vegetables, but within a one year period these spoilage defects became prevalent in the entire processing plant. Environmental sampling and microbiological analyses of the raw materials and final products throughout the manufacturing process highlighted the presence of high numbers of Leuconostoc spp. in halved and unseeded, fresh sweet bell peppers provided by the supplier. A combination of two DNA fingerprinting techniques facilitated the assessment of the species diversity of LAB present in the processing environment along with the critical point of their introduction in the production facility. Probably through air mediation and surface adhesion, mainly members of the strictly psychrotrophic species Leuconostoc gelidum subsp. gasicomitatum and L. gelidum subsp. gelidum were responsible for the cross-contamination of every vegetable handled within the plant.
为了调查即食（RTE）蔬菜沙拉产品在保质期结束时嗜冷乳酸菌水平过高的原因，对一家生产新鲜、轻度加工、包装且即食（RTE）蔬菜沙拉（储存于4°C）的公司进行了一项监测乳酸菌污染的研究。最初，含有各种切片和切块蔬菜的产品在保质期结束前（7天）出现了超过既定嗜冷菌阈值（>10(7)-10(8)CFU/g）的高微生物计数和腐败现象，但在一年内，这些腐败缺陷在整个加工厂变得普遍。对整个制造过程中的原材料和最终产品进行环境采样和微生物分析，结果表明供应商提供的半切且未去籽的新鲜甜椒中存在大量明串珠菌属。两种DNA指纹技术的结合有助于评估加工环境中存在的乳酸菌物种多样性以及它们引入生产设施的关键点。可能通过空气传播和表面粘附，严格嗜冷的明串珠菌属嗜冷亚种和气明串珠菌以及嗜冷明串珠菌嗜冷亚种的主要成员导致了工厂内处理的每种蔬菜的交叉污染。
