Foci of contamination of Listeria monocytogenes in different cheese processing plants

摘要: Abstract Listeria monocytogenes is a ubiquitous bacterium widely distributed in the environment that can cause severe disease humans when contaminated foods are ingested. Cheese has been implicated sporadic cases and outbreaks of listeriosis worldwide. Environmental contamination, several occasions by persistent strains, considered an important source finished product contamination. The objectives this research were to (i) evaluate presence L. within factory environments cheeses three processing plants, artisanal producer raw ewe's milk (APC), small-scale industrial cheese (SSI) (ICP) each producing distinct style cheese, all with history contamination (ii) identify possible sources using different typing methods (arsenic cadmium susceptibility, geno-serotyping, PFGE). markers specific for 3 epidemic clones (ECI–ECIII) was also investigated. Samples collected from (n = 179), whey (n = 3), brining solution (n = 7), brine sludge (n = 505), (n = 3016), (n = 2560) during, at least, four-year period. detected environmental, samples, respectively, 15.4%, 1.1% 13.6% APC; 8.9%, 2.9% 3.4% SSI; 0%, 21.1% 0.2% ICP. Typing isolates revealed dairy plant some strains persisted least four years environment. Although produced plants investigated never associated any case or outbreak listeriosis, belonging PFGE types caused (including putative clone isolated final products) found study.