Microbiological interactions between lactic acid bacteria and saccharomyces cerevisiae brewer’s yeast in mixed culture for effective production of a kefir type product

Authors:
Adriana Paucean, Mihaela-Ancuta Rotar, Mirela Jimborean, Elena Mudura, Carmen Socaciu

Changes in certain microbiological parametres of a kefir type were studied during the shelf-life of this product. Kefir batches were prepared using mesophilic starter culture, a single strain yeast Debaryomyces hansenii and brewer’s yeast, Saccharomyces cerevisiae, which were inoculated in skim milk, incubated at 30ºC and stored at 4ºC. The study was realized during the storage period of product, at the beginning, at the middle and at the end of the validity period. The co-cultivation of these microbiological species caused the inhibition of lactic acid flora by yeast Saccharomyces cerevisiae. The lactic acid flora decreased under the limits which are required by the legislation for kefir while yeasts’ numbers increased very much exceeding the limits