BACTERIAL FLORA OF PREFROZEN DRY-CURED HAM AT THREE PROCESSING TIME PERIODS AND ITS RELATIONSHIP TO QUALITY

Abstract

Hams frozen, stored, thawed, and dry-cured were sampled microbiologically after thawing, after curing, and after 30 days aging at about 34.5 C and about 62.5% relative humidity. Selective isolation techniques were made on samples from the surface of the butt, shank, and cushion surfaces and internally from the butt, shank, cushion, knuckle, semitendinosus, and biceps femoris of each ham. Surface samples and intra-muscular shank samples contained the greatest total number of microorganisms. Coagulase-negative Staphylococcus aureus were present in highest numbers at each ham location and at each processing time. The number of microbial cells per gram increased after curing above that in the fresh hams and then decreased generally after aging. No adverse effects on quality were observed and quality appeared unaffected as bacterial numbers changed. Lancefield D group streptococci, Staphylococcus epidermidis, and species of Micrococcus, Proteus, and Bacillus were present in low numbers within the hams. Moisture content appeared to be the limiting factor of bacterial growth; however, salt tolerant microorganisms were the predominant flora. Variations in pH did not appear to influence the microbiology of the hams. Bacteria of public health significance were not isolated on or within the ham tissues.