STAPHYLOCOCCUS-AUREUS GROWTH AND ENTEROTOXIN PRODUCTION IN MUSHROOMS

An enterotoxin A (SEA) producing strain of Staphylococcus aureus was inoculated onto mushrooms and incubated under simulated pre- and post-canning conditions. S. aureus grew and produced SEA in mushrooms incubated at 25-degrees-C in 10% to 20% NaCl. Growth and SEA production occurred when mushrooms were stored in plastic bags at 37-degrees-C, but not at 25-degrees-C. Mushrooms heat-processed at 121.1-degrees-C supported S. aureus growth and SEA production. No SEA was recovered from mushrooms inoculated with 1 or 10 ng SEA/g and heated at 121.1-degrees-C for 4.5 min. At higher inoculated SEA levels (100 and 1,000 ng/g), SEA was detectable after 10 min of heating. Staphylococcal enterotoxin could be present in canned mushrooms as a result of pre-, but more likely post-processing contamination.