Anti-listerial activity and biodiversity of cheese surface cultures: influence of the ripening temperature regime

Abstract

Undefined microbial surface ripening consortia with anti-listerial activity were derived twice from mature retail red smear cheeses produced in factories R and K. Each of the four consortia (R Ι, R ΙΙ, K Ι, K ΙΙ) was used for inoculation of soft cheeses, which were ripened according to two temperature regimes (13 °C, 13 d and 16 °C, 13 d/12 °C, 7 d, respectively) and subsequently stored at 8 °C. The protective potential of the cultures was determined by monitoring the growth of Listeria monocytogenes on the cheeses. While the protective potential of R Ι and R ΙΙ was stable under both temperature regimes, the anti-listerial activity of cultures from factory K was affected by the ripening temperature. Identification of 1200 isolates revealed significant changes in the bacterial composition of all four consortia until the expiry date, while the flora successions clearly varied with different temperatures. It is shown that the temperature effect on the anti-listerial activity and composition of protective cultures in food production are individual characteristics of the respective consortia that can be monitored and used to optimize its contribution to food safety.