The study, by Sadhana Ravishakar et al at the University of Arizona, showed that PET plastic films infused with apple and one of the antimicrobial ingredients both demonstrated the ability to inhibit development of the bacteria.
The film’s natural ingredients may also garner greater consumer approval, added the research published in the Journal of Food Science.
The effectiveness of the edible films depended on the dose of and the temperatures at which the wrapped meats were stored. The films with cinnamaldehyde were more effective than those with carvacrol, while reductions at 23°C were greater than those at 4°C, said the scientists.
A study from the same university published din the same journal in 2009 also linked use of edible wraps with a reduction of E.coli and Listeria on fresh meats.
Methodology and results
Retail chicken breast samples inoculated with D28a and H2a (resistant strains) and A24a (a sensitive strain) were wrapped in apple films containing cinnamaldehyde or carvacrol at 0.5 per cent, 1.5 per cent, and 3 per cent concentrations, and then incubated at 4 or 23°C for 72 hours.
Samples were tested for colonies of C. jejuni both immediately after wrapping and at 72 hours. The US group found the efficacy of the films was dose and temperature dependent.
Films with 1.5 per cent or more of cinnamaldehyde reduced populations of all strains to below detection at 23°C at 72 hours
At 4°C films with the same ingredient showed variable reductions for all strains, ranging from 0.2 to 2.5 logs and 1.8 to 6.0 logs at 1.5 per cent and 3.0 per cent, respectively.
Films with 3 per cent carvacrol stored at 23°C after 72 hours reduced populations of A24a and H2a to below detection, as well as cutting D28a levels by 2.4 logs.
A 0.5-log reduction was observed for both A24a and D28a, and 0.9 logs for H2a at 4°C at 3 per cent carvacrol.
Reductions ranged from 1.1 to 1.9 logs and 0.4 to 1.2 logs with 1.5 per cent and 0.5 per cent carvacrol at 23°C, respectively.
Greater consumer acceptance
The films could potentially be used in retail food packaging to cut C. jejuni on poultry, said the study. They may also gain greater consumer acceptance and serve as an additional food safety tool in the face of growing concern over resistance to traditional antimicrobials.
The group also said the ability of C. jejuni to “survive the harsh conditions of food processing suggests the need to find new antimicrobials to control contamination of the food supply”.
Antimicrobial Edible Apple Films Inactivate Antibiotic Resistant and Susceptible Campylobacter jejuni Strains on Chicken Breast by Rita M. Mild, Lynn A. Joens, Mendel Friedman, Carl W. Olsen, Tara H. McHugh, Bibiana Law, Sadhana Ravishankar published in the Journal of Food Science; DOI: 10.1111/j.1750-3841.2011.02065.x