In situ reuterin production by Lactobacillus reuteri in dairy products

In situ reuterin production during the manufacture and storage of two dairy model systems elaborated from milk supplemented with an optimized concentration of glycerol (50 mM) and inoculated with a commercial starter and with different reuterin-producing Lactobacillus reuteri strains was investigated. L. reuteri was able to survive and to produce reuterin in cheese and yogurt models. The highest reuterin production was achieved by L. reuteri INIA P572 and INIA P579, which displayed reuterin concentrations up to 5.5 mM in cheese and up to 1.5 mM in yogurt. The addition of reuterin-producing L. reuteri and glycerol to milk reduced the viable counts of the cheese starter from day 10 onwards, while did not influence the counts of the yogurt starter, compared to control dairy models without L. reuteri. Strains L. reuteri INIA P572 and INIA P579 could be promising candidates in the development of bioprotective cultures to control pathogenic microorganisms in dairy products due to the potentially inhibitory concentrations of reuterin achieved in situ.