The growth, properties and interactions of yeasts and bacteria associated with the maturation of Camembert and blue-veined cheeses

The growth of yeasts and bacteria were monitored during the maturation of C amembert and blue-veined cheese produced in Australia. Yeasts were prominen t throughout maturation, growing to 10(5)-10(9)/g, depending on the manufac turer. Debaryomyces hansenii predominated, but there were lesser, inconsist ent contributions from Yarrowia lipolytica. Of the non-lactic acid bacteria , Acinetobacter species were significant during the maturation of Camembert but not blue-veined cheeses, and grew to 10(6)-10(8) cfu/g. Staphylococcus and Micrococcus species were consistently isolated from the cheeses with S taphylococcus xylosus growing to 10(5)-10(9) cfu/g, depending on the produc t. Lactic acid bacteria (10(7)-10(9) cfu/g) were present throughout maturat ion but were not identified. Interactions between the various yeasts and ba cterial isolates were examined. Several strains of D. hansenii exhibited ki ller activity but not against Y. lipolytica. None of the yeasts were antago nistic towards the bacteria but some strains of D. hansenii enhanced the gr owth of Y. lipolytica and S. xylosus. The yeast and bacterial isolates exhi bited various degrees of extracellular proteolytic and lipolytic activities . (C) 2001 Elsevier Science B.V. All rights reserved.