MICROBIAL CHANGES IN NATURAL AND ALGAL YOGURTS DURING STORAGE

Storage experiments were carried out so as to study the changes in the microbial flora of stirred yoghurt samples enriched with a microalgal biomass and in that of control samples for 35 days at 4 degrees C and 15 days at 15 degrees C. Along with the microbiological investigation s, the pH of the samples was also measured. A characteristic viable ce ll count of over 10(8) cfu g(-1) was detected both in the control and in the algal yoghurt samples, regardless of storage temperature. Howev er, the viable cell counts were significantly higher in the case of th e algal yoghurt at 4 degrees C. The count of moulds and yeasts amounte d to a level of 10(1) cfu g(-1) by the sixth day and to a level of 10( 5) cfu g(-1) by the fifteenth day of the storage period at 15 degrees C, while the algal yoghurt, if stored at 4 degrees C, is guaranteed to have a shelf-life of one month even if manufactured under non-aseptic conditions.