Moisture requirements for lactic acid bacteria producing diacetyl

ABSTRACT

An investigation was done to assert the influence of water activity on 2 mixtures of bacterial cultures, containing Streptococcus cremoris, Str. lactis, Str. diacetilactis, and Leuconostoc mesenteroides subsp. Cremoris, on production of diacetyl compound. Diacetyl production by the 2 cultures gradually increases during incubation at 21C up to 24 h, and then started to drop down. Such a drop in diacetyl content could be stopped when the media were refrigerated at 2C, where considerable increase in this compound level could be maintained. Diacetyl production under a wide range of water activity levels tested was inversely proportional to water activity. The level of the aroma compound was highest at pH values around 5 but not detected at pH higher than 6