SUMMARY—Macaroni and cheese, blueberry. pie, and beef gravy served as carriers for various bacteria including Escherichia coli, Proteus vulgaris, Pseudomonas fluorescens, Pseudomonas aeruginosa, Pseudomonas geniculata, or a mold, Chrysosporium pannorum. The foods were inoculated with l,000,000 bacterial cells per gram or 250 mg, wet weight, of mold and compared with uninoculated samples after various intervals of frozen storage. Special effort was made to reduce the holding period both previous to freezing and for thawing to a minimum. A taste panel evaluated storage time and types of microorganisms for their effects on flavor and aroma, and found that in a limited number of instances the presence of certain microorganisms appeared to influence the flavor and aroma of food directly. More frequently, however, alterations in flavor or aroma developing during frozen storage seemed to be attributable either partially or wholly to factors other than the presence of or reactions incited by the microorganism
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