Safety clearances for the Liebefeld cultures

The microbial strains that Agroscope uses for practical trials and which, if successful, subsequently become part of a defined mixed culture, must demonstrate a high level of safety. With this end in view, 186 strains of lactic acid bacteria from the Agroscope Culture Collection were tested for transferable antibiotic resistances, the formation of biogenic amines, and the presence of virulence factors. Only six strains had one or more transferable antibiotic resistances, and thus had to be ruled out. These strains were only isolated a few years ago. By contrast, the majority of strains from the Culture Collection were isolated several decades ago, at a time when resistances were probably not yet spread to such a large extent as they are today. The Culture Collection is also of inestimable value owing to its high biodiversity and the large number of strains it contains.