Cranberry and oregano extracts combined with lactic acid may inhibit the growth of bacteria in meat and fish, say researchers from the University of Massachusetts.

Their findings appear in Applied and Environmental Microbiology.

Listeria monocytogenes, the cause of many food-borne illnesses throughout North America and Europe, is a bacterium capable of growing in refrigerated temperatures, making it very difficult to control. Listeriosis carries a high mortality rate and is therefore regarded as a serious problem worldwide.

In the study, a combination of oregano and cranberry extracts (75% oregano and 25% cranberry) was applied to meat and fish and refrigerated at 39 degrees F. Antimicrobial activity in meat and fish increased as a result of treatment with the mixture and was further enhanced by the addition of lactic acid.

"Oregano and cranberry, useful botanicals generally regarded as safe for food flavoring and as functional ingredients are known for their antimicrobial activity linked to the phenolic moiety and therefore are suitable as antimicrobial natural extracts when effectively combined with lactic acid," said the researchers (Lin YT, Labbe RG, Shetty K, et al., "Inhibition of Listeria monocytogenes in fish and meat systems by use of oregano and cranberry phytochemical synergies." Appl Environ Microbiol, 2004;70(9):5672-5678).