Department of Food Science and Technology, International Campus of Excellence in the AgriFood Sector ceiA3, University of Córdoba, Córdoba, Spain.
R&D&i, National Centre for Technology and Food Safety, San Adrian, Spain.
Int J Food Microbiol. 2014 Aug 1;184:86-91. doi: 10.1016/j.ijfoodmicro.2014.05.013. Epub 2014 May 27.
Fecal pathogen distributions in fresh-cut leafy vegetables are essential to develop suitable sampling plans so as to detect pathogen contaminations. In this study, a typical fresh-cut lettuce process was reproduced at pilot scale with different initial inoculum levels of Salmonella on lettuce (6-7, 4 and 1 log CFU/g). The pathogen was determined in all processed lettuce samples (n ≥ 50) and obtained count data were used to fit different probability distributions. The study showed that Salmonella is homogenously distributed on fresh-cut leafy vegetables as a result of processing (mainly washing) at all contamination levels. Negative binomial and Poisson-lognormal distributions were suitable to describe pathogen distribution at the high and medium levels. coefficient of variation modified (CV) indicated no overdispersion (i.e. clustering). Nevertheless, further research will be needed to assess the effect of using disinfectants in washing water on the final distribution pattern of pathogens in processed fresh-cut leafy vegetables.
在新鲜切碎的叶类蔬菜中，粪便病原体的分布对于制定合适的抽样计划以检测病原体污染至关重要。在本研究中，采用不同初始接种水平的沙门氏菌（6-7、4 和 1 log CFU/g）在中试规模上再现了典型的新鲜切碎生菜工艺。在所有加工的生菜样品（n≥50）中均检测到病原体，并使用获得的计数数据拟合不同的概率分布。研究表明，沙门氏菌在所有污染水平下均均匀分布在新鲜切碎的叶类蔬菜中，这是由于加工（主要是洗涤）所致。负二项式和泊松-对数正态分布适用于描述高和中水平的病原体分布。修正变异系数（CV）表明不存在过分散（即聚类）。然而，仍需要进一步研究，以评估在洗涤水中使用消毒剂对加工后的新鲜切碎叶类蔬菜中病原体最终分布模式的影响。
