Survival of E. coli O157:H7 during manufacture of dry‐cured Westphalian ham surface‐treated with allyl isothiocyanate or hot mustard powder

BACKGROUND: Escherichia coli O157:H7 can survive commercial manufacture of some uncooked fermented meats. External application of microencapsulated allyl isothiocyanate (AIT) or hot (non‐deheated) yellow mustard powder was used to inactivate the pathogen during dry‐cured Westphalian ham manufacture. RESULTS: Within 45/80 days, E. coli O157:H7 numbers were reduced 5 log10 CFU g−1 by 400 µg kg−1 AIT or 60 g kg−1 mustard powder, but 80 days were required in the untreated control. Mustard powder but not AIT reduced numbers of lactic acid bacteria and staphylococci. Mustard powder or ≥ 300 µg kg−1 AIT inhibited yeasts and moulds but did not affect ham pH or water activity. CONCLUSION: The commercial Westphalian ham process without AIT or mustard powder treatment was validated capable of reducing E. coli O157:H7 5 log10 CFU g−1. Surface treatments with ≥ 300 µg kg−1 microencapsulated AIT or 60 g kg−1 yellow mustard powder reduced the time required for this reduction by 40–50%. AIT volatility from microcapsules or hot mustard powder during application of these compounds may restrict their use in production facilities.