Microbial and Acidity Changes in Colostrum Fermented by Natural Flora at Low and High Ambient Temperatures

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Abstract
The effects of 2 ranges of ambient temperature on natural fermentation of colostrum were studied over a 32 day storage. Colostrum from the first 6 milkings of 8 Holstein cows, 4 in winter and 4 in late spring, was stored separately in 75.7 l plastic containers with lids. Total plate counts were maximal on the 1st plating, .apprx. 109/ml, and declined little during winter storage (8-15.degree. C) but showed a 1.5 log cycle decline between day 2-16 of spring storage (20-27.degree. C). Total lactic acid bacteria declined little over 32 days of winter storage but showed a 1.5 log cycle decline between day 4-16 of spring storage. After 32 days lactobacilli counts were 9 .times. 107 and 4 .times. 107/ml and comprised 30% and 7% of the total lactic acid bacteria during spring and winter storage, respectively. By day 16 coliforms were .apprx. 2 log cycles less in spring storage samples than in winter storage. Coliforms counts never declined < 104/ml by day 32 of storage. Total yeasts and molds, although initially lower during winter fermentation, appeared to stabilize at 106 colonies/ml at both temperature ranges. From day 0-32 titratable activity values increased from 1.1 to 3.8% in spring storage samples and increased from .9 to 1.9% in winter storage samples. Higher fermentation temperature may favor development of a more desirable microflora in the colostrum.