title: Combined effect of gamma irradiation, ascorbic acid, and edible coating on the improvement of microbial and biochemical characteristics of ground beef.
abstract: This study was conducted to evaluate the combined effect of gamma irradiation and the incorporation of natural antimicrobial compounds in cross-linked films on the microbiological and biochemical characteristics of ground beef. Medium-fat (23% fat) ground beef patties were divided into three separate treatment groups: (i) control samples without additives, (ii) ground beef samples containing 0.5% (wt/wt) ascorbic acid, and (iii) ground beef samples containing 0.5% ascorbic acid and coated with a protein-based cross-linked film containing immobilized spice powders. Meat samples were irradiated at doses of 0, 1, 2, and 3 kGy and stored at 4 +/- 2 degrees C. Microbial growth (based on total aerobic plate counts [APCs] and total coliforms) was evaluated, as were the content of thiobarbituric acid-reactive substances (TBARS) and that of free sulfydryl groups. At the end of the storage period, Enterobacteriaceae, presumptive Staphylococcus aureus, presumptive Pseudomonas spp., Brochothrix thermosphacta, and lactic acid bacteria were enumerated. Regardless of the treatment group, irradiation significantly (P < or = 0.05) reduced the APCs. Irradiation doses of 1, 2, and 3 kGy produced immediate APC reductions of 2, 3, and 4 log units, respectively. An APC level of 6 log CFU/g was reached after 4, 7, and 10 days for samples irradiated at 1, 2, and 3 kGy, respectively. Lactic acid bacteria and B. thermosphacta were more resistant to irradiation than were Enterobacteriaceae and Pseudomonas. The TBARS and free sulfydryl contents were stabilized during postirradiation storage for samples containing ascorbic acid and coated with the protein-based cross-linked film containing immobilized spice powders.
authors.affiliation: Canadian Irradiation Center, Research Laboratories in Sciences Applied to Food, Institut National de Recherche Scientifique-Institut Armand-Frappier, Laval, Québec.
authors.forename: Blaise
authors.initials: B
authors.lastname: Ouattara
authors.forename: Martine
authors.initials: M
authors.lastname: Giroux
authors.forename: Wanda
authors.initials: W
authors.lastname: Smoragiewicz
authors.forename: Linda
authors.initials: L
authors.lastname: Saucier
authors.forename: Monique
authors.initials: M
authors.lastname: Lacroix
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000494:pharmacology*; D001205:Ascorbic Acid / Q000494:pharmacology*; D018441:Biofilms; D002417:Cattle; D015169:Colony Count, Microbial; D004307:Dose-Response Relationship, Radiation; D005511:Food Handling / Q000379:methods; D005514:Food Irradiation / Q000379:methods*; D005720:Gamma Rays; D008461:Meat Products / Q000382:microbiology* / Q000528:radiation effects / Q000592:standards; D017392:Thiobarbituric Acid Reactive Substances / Q000032:analysis; D013997:Time Factors
chemical_list: D000975:Antioxidants; D017392:Thiobarbituric Acid Reactive Substances; D001205:Ascorbic Acid