Growth potential of Yersinia enterocolitica in blue cheese and in blue cheese with probiotic -Lactobacillus acidophilus LA-5®

Abstract

In the annual reports of the European Food Safety Authority (EFSA), Yersinia enterocolitica (YE) is enumerated as the third most common enteric pathogen responsible for food poisonings. The objective of the paper was to determine the potential for Yersinia enterocolitica growth in blue cheese and in blue cheese with a probiotic (Lactobacillus acidophilus LA-5®). The experiment was carried out with five different cheese batches. The potential of YE growth was determined at 3, 6, 9, 12 and 15 °C in ten time intervals up to 480 h of storage. The initial contamination level was set at ~103 cfu/g YE. The studies demonstrated that at lower temperatures there was a systematic increase in the number of cells throughout the storage period, whereas at higher temperatures stationary and die-off phases were observed. By comparing the increase in the number of YE cells in both cheese varieties, it may be observed that at 6, 9 and 12 °C the number of YE cells was lower in blue cheese with probiotic than in blue cheese at each stage of the experiment although it did not guarantee the microbiological safety of the product.