Bacterial growth in whey from mastitic and nonmastitic quarters.

Growth of Escherichia coli and Staphylococcus aureus was analyzed by turbidometry in 456 selected whey samples. The samples had been graded mastitic or nonmastitic as determined by antitrypsin assay and bacteriologic examination. Whey samples from inflamed quarters (antitrypsin increased) and infected quarters significantly promoted bacterial growth as compared with whey samples from control quarters. The growth-stimulatory effect was limited to the diseased quarters, since control quarters from the same animals did not support enhanced bacterial growth. The observations indicate that in chronic mastitis, the inflammatory process leads to changes in the whey that promote bacterial growth in vitro.