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R. A. ROSE-MORROW¹, M. A. Harrison, and A. E. Reynolds. (1) Food Science and Technology, University of Georgia, Cedar St., Athens, GA 30602-7610

The USDA/ FSIS Pathogen Reduction: Hazard Analysis and Critical Control Point System regulations require validation of ready-to-eat product production procedures to ensure adequate control of pathogenic microorganisms. The dry curing process for country ham has not previously been validated for the control of Staphylococcus aureus, Listeria monocytogenes, Escherichia coli O157:H7, or Salmonella spp.

This study was initiated to evaluate the ability of the dry curing process of hams to control these pathogens.

The challenge study followed the protocol delineated by USDA/FSIS, with slight modification, for determining efficacy of processing dry cure, fermented products. Fresh hams were surface inoculated (5 x 5 cm ² areas) on the ham cushion, butt, and hock with a suspension of each microorganism prior to the application of a commercial cure mix. Commercial style conditions using Trichina treatment according to USDA recommendations were followed.

Moisture content, salt content, pH, and water activity were measured throughout the 120 day process. The mean log reduction of populations for S. aureus, L. monocytogenes, E. coli O157:H7, and Salmonella spp. after 120 days of curing were 1.2, 4.8, 5.3, and 5.7 CFU/ cm², respectively. At day 120, Salmonella spp., L. monocytogenes, and E. coli O157:H7 organisms were not detectable when the appropriate enrichment media was used. Analysis of data showed no significant (p<0.05) difference in the reduction of microbial populations between ham sampling locations. The a_w of the hams was below 0.91 which is considered sufficient to limit enterotoxin production by S. aureus on this type of product with the interactions of pH (5.5), temperature (20°C), and salt (5-6%).

Results of this study show the pathogens tested were controlled by the curing and aging process. The achievement of low water activity provides assurance of a safe and stable product.