Safety assessment of dairy microorganisms: the Enterococcus genus

Unlike most of lactic acid bacteria, the Enterococcus genus is not considered "generally recognized as safe" (GRAS). Safety assessment for enterococci remains controversial. While enterococci are considered "positive" or useful in cheese technology, isolates of this genus have emerged as opportunistic pathogens for humans. Thus these bacteria have the paradoxical position of being useful in dairy fermentations, but also potentially dangerous. The aim of this review is to summarize both the positive and negative traits of enterococci that illustrate the controversial nature of this bacterial genus. According to food safety assessment guidelines, we propose a case-by-case evaluation of each potential technological strain and suggest several lines of research before using enterococci in fermented food products.