Effect of Freezing and Storage at −20 C on Survival of Mastitis Pathogens

Mine cultures of Staphylococcus aureus, 19 of Staphylococcus epidermidis, 9 of Streptococcus agalactiae, and 10 of other streptococci were selected to determine if storage at --20 C would significantly decrease pathogens in mastitic milk.Staphylococci and other streptococci did not decrease significantly during 70 days of storage whereas S. agalavtiae decreased significantly.During the first 14 days of storage, however, S. agalactiae did not decrease significantly.Mastitic milks can be held up to 14 days at --20 C without endangering the isolation of staphylococci or streptococci.