The effectiveness of different spices, as inhibitors for Escherichia coli O157 : H7, in nutrient broth stored at 4 degrees C or 12 degrees C

The behaviour of E, coli 0157:H7 in tryptic soy broth (TSB) containing diff erent concentrations of spices (onion, garlic, chili, cinnamon, rosemary) s tored at 4 degreesC or 12 degreesC for 10 days was investigated. Of the fiv e spices examined for antibacterial activity, chili was the least effective and cinnamon was the most effective in almost all tests conducted. Specifi cally, the spices screened for their inhibitory activities against E, coli 0157:H7 in TSB, could be divided into three groups on the basis of their de gree of effectiveness. Chili at concentrations up to 2% exhibited slight to xicity with or without effect when stored at 4 degreesC or 12 degreesC. Oni on was moderately inhibitory over the same concentration range, while cinna mon, garlic and rosemary were highly bactericidal when present at a level u p to 1 % and stored at 12 degreesC. The highest concentration (2 %) of cinn amon, garlic and rosemary into TSB was sufficient to reduce the population of E. coli 0157:H7 to a non-detectable level (< 10 cfu/ml) after 10 days.