Fate of Salmonella spp., Escherichia coli O157:H7 and Listeria monocytogenes during the manufacture of dry cured Westphalian-style Ham S. Balamurugan1, Carlos G. Leon-Velarde2, Saleema Saleh-Lakha2 1Guelph Food Research Centre, Agriculture & Agri-Food Canada, Guelph ON 2Laboratory Services Division, University of Guelph, Guelph ON INTRODUCTION ANALYSIS RESULTS & DISCUSSION Treatments Schedule of sampling For sampling, 3-12.5 cm2 area cores (Fig. 4) were taken from each ham, homogenized and bacteria enumerated by plating on selective media. Westphalian ham is a dry cured, ready-to-eat product that is manufactured without a lethal heat treatment. Hams are preserved by a process that involves: curing with salts and spices; fermentation; smoking; and drying. These processes have to be validated to successfully control the growth of pathogens. Treatment Inoculated Bioprotective Culture (CHR Hansen) P1 Inoculum Cocktail C-P-77 P1 Control No P2 C-P-77 and B-SF-43 P2 Control MATERIALS & METHODS Process Steps Time point (day) Enumeration of inoculated strains aw Presence of Target Organism Total Viable Count Raw Ham Inoculated Raw Ham Uninoculated Raw Ham Salting 3 P1/P2   14 28 P1/P2 Controls Smoking 35 Drying 63 70 D0: Surface Inoculate ham Cocktail (108 CFU cm-2) Store @ 4°C overnight D1: Salting Ham Starter culture and dry rub mixed together Dry rub amount ≥4.3% start weight of meat Material rubbed until all sides are covered See Fig. 1 Strain (ATCC #) Source E. coli O157:H7 43889 Human L. Monocytogenes 19115 S. enterica sp. Berta 8392 Unknown Salmonella spp. and E.coli O157:H7 decreased by at least 5-log cm-2, regardless of starter culture. L. monocytogenes decreased 4.41 and 5.36-log cm-2 for C-P-77 and C-P-77/ B-LC-48, respectively. Greatest decrease for all pathogens occurred during first 28 days Total viable count of uninoculated hams Initial count was 2.83-log cm-2; Slow increase to 5.01-log cm-2 after 28 days; Under high salt conditions and 4°C. Rapid increase to 7.73-log cm-2 by day 35; Increased temperature in smoking chamber. Final count was 9.04 log cm-2 after 70 days. aw dropped from 0.98 (day 1) to between 0.93 & 0.90 (day 70, P1 & P2 respectively). D128: Pressing Hams placed into bins, Stored @ 4°C Bins stacked 4 high Rotated top to bottom each week D2935: Smoking Hams removed from bins, placed onto racks in the smoke chamber (Fig. 2) Temp: varied between 18-27°C RH: varied between 70-88% Smoke injected into chamber Bacteria Growth Media Appearance E. coli O157:H7 BBL™ CHROMagar™ O157 Mauve colonies w/ translucent borders L. monocytogenes ALOA® Listeria monocytogenes Chromogenic agar (bioMerieux SA) Blue colonies w/ opaque halo Salmonella spp. Oxoid™ Brilliance Salmonella Agar Purple colonies on white agar Total viable counts 3M™ Petrifilm™ Aerobic Count Plates Red colonies 1 Fig. 1: Raw ham in dry rub 2 Fig. 2: Hams in smoke chamber 3 Fig. 3: Final Product (cross section) 12.5 cm2 core 4 Fig. 4: Ham showing sample core D3670: Drying Placed into drying chamber Temp: 13°C RH: 75% Completed @ 70 days See Fig. 3 Conclusion The process for the manufacture of dry cured Westphalian-style Ham is adequate for the reduction of Salmonella spp., E. coli O157:H7, and L. monocytogenes by at least 4.4 to 5.4-log regardless of the bioprotective/fermentation culture used.