Extended shelf life milk processing : effect of simulated cleaning in place on the germination and attachment of Bacillus cereus spores

Abstract

The effect of simulated cleaning in place (CIP) was determined on the structure, attachment and growth of Bacillus cereus spores isolated from raw milk and biofilms in filler nozzles from extended shelf life (ESL) milk processing lines. Simulated CIP treatment structurally affected >98% of B. cereus spores, while 0.1% remained intact. Following simulated CIP treatment, B. cereus spores were able to attach to stainless steel coupons and form biofilms. B. cereus spores were capable of germination and growth under refrigerated conditions for more than 28 days. Contamination with B. cereus spores may lead to a reduced shelf life and potentially be a safety risk in ESL milk with a prolonged shelf life.