Adhesion to stainless steel surfaces and detection of viable but non cultivable cells of Vibrio parahaemolyticus and Vibrio cholerae isolated from shrimps in seafood processing environments: Stayin' alive?

摘要

A single strain of Vibrio parahaemolyticus and a single strain of Vibrio cholerae were isolated from shrimps sourced from seafood processing plants. The isolated strains were evaluated for their ability to adhere to stainless steel surfaces, under conditions encountered in seafood industries. In this way, the impact of different environmental factors such as temperature (8 degrees C or 37 degrees C) and culture media (tryptic soy broth (TSB) 2% NaCl, artificial sea water (ASW) or industrial brine) were studied. The viability of these strains was analyzed by three different methods: the enumeration of cultivable bacteria on agar media, and two PCR methods, i.e. a qPCR and a PMA-qPCR method in order to distinguish between viable and dead cells. The proportion of viable but non-cultivable (VBNC) cells was evaluated by comparing the results of propidium monoazide real-time PCR (PMA-qPCR) with the enumeration results. Cultivable bacteria were not detected in brine, regardless of the conditions tested. However, V. cholerae in the VBNC state was detected in brine at 8 degrees C until 48 h of incubation. V. cholerae exhibited higher viability at 8 degrees C compared to 37 degrees C. V. cholerae also exhibited higher viability compared to V. parahaemolyticus. In contrast, for V. parahaemolyticus, temperature and media (except industrial brine) had little influence on cell viability and adhesion behavior.