78. A Study of the Quantitative Changes in the Microbiological Flora of Sweet-Cream Salted Butter of Good Keeping Quality when held at 15° F. for a Period of Two to Eight Months

Abstract

1. Data, taken over a period of eight months, are presented, concerning the quantitative changes which take place in the microflora of sweet-cream salted cold-stored butter of good keeping quality.2. Tables showing the influence of varying periods of cold storage on the development of acidity, total bacterial count, yeasts, moulds, gelatin liquefying bacteria and types of micro-organisms in forty-nine churnings of butter cold stored at 15° F. are given.3. There was a slight increase in the titratable acidity.4. There was a noticeable increase of the yeast count, in many cases without apparently injuring the keeping quality.5. The numbers of Oidium lactis present tended to decrease.6. The following types of bacteria persisted in the sweet-cream salted butter in decreasing numbers: (a) various types of micrococci; (b) lactic acid bacteria of non-coagulating and acid coagulating types, including “slow” varieties of Str. lactis; (c) acid with coagulation and gas; (d) rennet digesting; (e) alkaline-forming; (f) alkaline digesting.