Tests showed that the two plant-derived antimicrobials, carvacrol and cinnamaldehyde, inactivated pathogenic bacteria on contaminated chicken breast and cooked ham. They could also be used for other contaminated food products such as seafood, say the researchers.
During experiments at the University of Arizona, United States, E.coli cultures were surface inoculated on chicken breasts and Listeria monocytogenes on ham. The inoculated products were then wrapped with edible films containing the plant antimicrobials cinnamaldehyde or carvacrol at three concentrations: 0.5 per cent, 1.5 per cent, and 3 per cent.
Pathogenic bacteria
After incubation at either 23°C or 4 °C for 72 hours, samples were screened for existence of pathogenic bacteria. Chicken breasts incubated at 23°C wrapped with film treated with 3 per cent antimicrobials showed the highest reductions of both S. enterica and E.coli O157:H7. Films with 1.5% and 0.5% antimicrobials showed significant but relatively smaller reductions.
At the lower temperature incubation, carvacrol showed greater antimicrobial activity than did cinnamaldehyde.
The latest findings complement and extend other studies which also identified the inactivation of foodborne pathogens by the same antimicrobials added to ground meats.
The scientists concluded: “The results suggest that the food industry and consumers could use these films as wrappings to control surface contamination by foodborne pathogenic microorganisms.” So incorporating antimicrobials into edible films could serve as barrier for surface-contaminating microorganisms in a range of meat products.
The test products used in the study were skinless, boneless chicken breast, and cooked ham obtained from local stores.
Test products
The study was conducted at the Department of Veterinary Science and Microbiology,
University of Arizona, Tucson.
Meanwhile, in May a report from the European Food Safety Authority and the European Centre for Disease Prevention and Control identified Salmonella as the European Union’s most common cause of food-borne illness in 2007.
Food-borne viruses and Campylobacter were the second and third most common forms of illness identified in their joint Community Summary Report on Food-borne Outbreaks in the EU in 2007.
A total of 5,609 outbreaks of food-borne illness were reported, nearly 40,000 people were affected and 19 died. The findings represent a small decrease on the totals reported in 2006. The cause of five of the 19 deaths arising from food-borne outbreaks could not be identified.