Purpose: The objective of this research was to examine the effectiveness of commercial treatment of whole black peppercorns and cumin seeds with ethylene oxide on the survival of Salmonella enterica, Enterococcus faecium, and total aerobic bacteria.
Methods: Whole black peppercorns and cumin seeds were inoculated with a Salmonella cocktail or Enterococcus faecium NRRL B-2345 using agar grown cells, and the spices were dried to aw 0.3 to 0.5. Spices were packaged (5 lb) in polywoven bags (n=3) and shipped to a commercial processor for EtO treatment using FDA approved spice treatment parameters and returned by overnight shipment. Cells were enumerated by serial dilution and plating onto TSA for aerobic plate counts or TSA with a thin overlay of XLT4 for Salmonella, or BEA for E. faecium.
Results: Ethylene oxide fumigation significantly reduced the populations of Salmonella and E. faecium on whole black peppercorns and cumin seeds (P<0.05). Reductions of Salmonella on peppercorns (6.62±0.66 log CFU/g) were significantly greater than those for Enterococcus (P=0.05, 2.96±0.66 log CFU/g). Reductions of Salmonella and Enterococcus on cumin seeds were not significantly different (P=0.38; 4.9 and 4.3 log CFU/g, respectively). EtO fumigation significantly reduced total aerobic plate counts for both spices by 2 to 3 log CFU/g.
Significance: Ethylene oxide fumigation offers a strategy to reduce Salmonella on whole spices. Further research examining gas penetration needs to be performed to verify that the process is adequately inactivating Salmonella using all packaging configurations.