Post-packaging irradiation combined with modified atmosphere packaging for control of bacterial pathogens on meat products
Li Kudra, Joseph G. Sebranek and Aubrey F. Mendonca
Thesis, Doctor of Philosophy (Food Science and Technology), Iowa State University. 332 pages. 2007.
2007
บทคัดย่อ
Foodborne illnesses caused by consumption of contaminated meat and poultry products with Escherichia coli O157:H7, Listeria monocytogenes, Salmonella or Campylobacter have been major concerns in the U.S. Therefore, control of these pathogens by irradiation combined with modified atmosphere packaging (MAP) was investigated. Ground beef patties were inoculated with E. coli O157:H7, frankfurters or pre-cooked pork chops were inoculated with L. monocytogenes, and fresh chicken breasts were inoculated with Salmonella enterica Typhimurium, or Campylobacter jejuni. Packaging in vacuum or high CO2 MAP (99.5% CO2 /0.5% CO for beef patties and chicken breasts; and vacuum or 100% CO2 for frankfurters or pork chops) was used for packaging these products. Products were treated with electron-beam irradiation at refrigerated temperature with target doses of 0 (control), 0.5, 1.0 and 1.5 kGy for beef patties and chicken breasts inoculated with Salmonella, 0, 1.0, 1.5 and 2.0 kGy for frankfurters and pork chops, and 0, 0.25, 0.5 and 0.75 kGy for chicken breasts inoculated with Campylobacter. Packaging methods did not affect radiation sensitivities of the pathogens. Radiation D10 -values, each in vacuum and high CO2 MAP, respectively, were 0.47 ± 0.02 kGy and 0.50 ± 0.02 kGy for E. coli O157:H7 on beef patties; 0.66 ± 0.03 kGy and 0.70 ± 0.05 kGy for L. monocytogenes on frankfurters, and 0.60 ± 0.02 kGy and 0.57 ± 0.02 kGy for this pathogen on pork chops; 0.55 ± 0.03 kGy and 0.54 ± 0.03 kGy for Salmonella on chicken breasts, and 0.31 ± 0.01 kGy and 0.29 ± 0.03 kGy for Campylobacter on chicken breasts. Although there was no increase in numbers, E. coli O157:H7, Salmonella and Campylobacter survived in both vacuum and MAP during post-irradiation storage. The growth of L. monocytogenes was inhibited in high CO2 MAP for 12 weeks compared to 7-9 weeks in vacuum. CO in MAP retained red ground beef color during irradiation. Sour-like aroma was detected in the products from high CO2 MAP, while irradiated off-odor was observed in all irradiated meat.