Screening and analysis of spices with ability to suppress verocytotoxin production by Escherichia coli O157.

To reduce the amounts of verocytotoxin (VT) produced by Escherichia coli O157:H7, various spices were screened for their ability to suppress VT production. Extracts of these spices were prepared with 70% ethyl alcohol. When E. coli O157:H7 cells were grown to the stationary phase at 37 degrees C in Luria-Bertani medium supplemented with 0.02% allspice extract, the production of both VT1 and VT2 was significantly reduced. Neither growth inhibition nor a delay in the lag phase was observed when the cells were cultured in the presence of 0.02% allspice extract. An active component of the allspice extract was purified by HPLC and was identified as eugenol. When we examined the suppressive effect of eugenol on VT production by E. coli O157:H7, the amounts of both intracellular and extracellular VTs were found to decrease with an increase in eugenol concentration. Our results suggest that eugenol is useful for reducing the virulence of E. coli O157:H7.

Enumeration of Aerobic Spore-Formers and Bacillus cereus in Meat Product Additives.

Microbial populations in 225 samples of meat product additives including spices, seasoning, proteins, starch, salt, sugar and colorants, were enumerated by means of aerobic plate counts (APC), aerobic spore counts (ASC), Bacillus cereus total counts (BcTC), and B. cereus spore counts (BcSC). Our data indicate that meat product additives with the exception of sugar and salt were contaminated mainly by aerobic spore-formers including B. cereus under spore-forming conditions. To improve the quality of meat products, it will be necessary to develop methods to reduce the bacterial contamination of meat product additives.