CLOSTRIDIUM SPOROGENES AND LISTERIA-MONOCYTOGENES - SURVIVAL AND INHIBITION IN MICROWAVE-READY BEEF ROASTS CONTAINING SELECTED ANTIMICROBIALS

Beef roasts were pumped with brines containing phosphates and acetic acid, sodium lactate, potassium sorbate, or glycerol monolaurin, and cooked in-the-bag once or twice to 62.8-degrees-C. Samples were examined during storage at 2, 5, and 10-degrees-C and after mishandling at 25-degrees-C for survival of inoculated Clostridium sporogenes spores and Listeria monocytogenes. Clostridia and listeriae survived one cooking when surface inoculated and two cookings in roasts inoculated internally. Lactate in brine afforded protection against clostridial survival and growth in temperature-abused roasts. Clostridia grew after 24 hr at 25-degrees-C in untreated roasts cooked once, and after 48 hr of abuse in most others except those with lactate or monolaurin. Listeria survival was reduced by lactate and monolaurin in recooked surface-inoculated roasts.