Source of Enterococci in a Farmhouse Raw-Milk Cheese

Abstract

Enterococci are widely distributed in raw-milk cheeses and are generally thought to positively affect flavor development. Their natural habitats are the human and animal intestinal tracts, but they are also found in soil, on plants, and in the intestines of insects and birds. The source of enterococci in raw-milk cheese is unknown. In the present study, an epidemiological approach with pulsed-field gel electrophoresis (PFGE) was used to type 646 Enterococcus strains which were isolated from a Cheddar-type cheese, the milk it was made from, the feces of cows and humans associated with the cheese-making unit, and the environment, including the milking equipment, the water used on the farm, and the cows' teats. Nine different PFGE patterns, three of Enterococcus casseliflavus, five of Enterococcus faecalis, and one of Enterococcus durans, were found. The same three clones, one of E. faecalis and two of E. casseliflavus, dominated almost all of the milk, cheese, and human fecal samples. The two E. casseliflavus clones were also found in the bulk tank and the milking machine even after chlorination, suggesting that a niche where enterococci could grow was present and that contamination with enterococci begins with the milking equipment. It is likely but unproven that the enterococci present in the human feces are due to consumption of the cheese. Cow feces were not considered the source of enterococci in the cheese, as Enterococcus faecium and Streptococcus bovis, which largely dominated the cows' intestinal tracts, were not found in either the milk or the cheese.

Production of bacteriocin-like substances by lactic acid bacteria isolated from regional ovine cheese

“…As shown in Table 1 On the other hand, antimicrobial activity against Enterococcus faecalis was not observed (Table 1). Enterococci were found in artisanal cheeses produced with sheep, goat, buffalo and cow pasteurized or raw milk, and E. faecalis and Enterococcus faecium were the most frequently species detected in cheeses (12). Similar absence of activity was observed against…”

Application of multilocus sequence analysis (MLSA) for rapid identification of Enterococcus species based on rpoA and pheS genes

“…Enterococci are natural inhabitants of the gastrointestinal tract of man and animals (Franz et al, 1999). E. faecalis, E. faecium, E. hirae and E. durans have been found in association with human faeces (Franz et al, 1999;Gelsomino et al, 2002), E. faecalis often being the dominant species (Godfree et al, 1997;Murray 1990). Enterococcus strains are also found in the oral cavity and the urogenital tracts of man (Morrison et al, 1997;Sedgley et al, 2004).…”

Effect of Raw-Milk Cheese Consumption on the Enterococcal Flora of Human Feces

“…In a previous study (16), the enterococcal flora of a raw-milk, farmhouse cheese was compared with the microflora of human and bovine feces. The cheese and the human feces contained two dominant strains of Enterococcus casseliflavus and one of E. faecalis and lower numbers of other clones from the two species.…”