Sensitivity of Listeria monocytogenes to Selected Spices

Ten spices were added separately to tryptose broth which was then inoculated to contain, per ml, 10⁵ or 10⁷ Listeria monocytogenes strain Scott A or V7, respectively, and held at 4°C for 7 d. Strain Scott A appeared to be more sensitive to effects of spices than was strain V7. The population of strain Scott A was decreased to <10/ml in 1 d by 1% sage, in 4 d by 1% allspice, and in 7 d by 1% cumin, garlic powder, paprika, and red pepper. Black pepper and mace at 1% reduced but did not completely inactivate the population of strain Scott A, whereas 1% white pepper enhanced its growth. At 1%, only sage reduced the population of strain V7 to <10, but 7 d rather than 1 d of storage were required. At 3 and 5%, some activity against strain V7 was exhibited by allspice, mace, and nutmeg. Generally, the antilisterial effect of spices increased as the concentration in the medium increased from 1 to 3 to 5% .