ABSTRACT
Ground Longissimus dorsi of beef were treated with herbal extracts of marjoram, rosemary and sage at concentration of 0.04% (v/w), radiation (2 or 4.5 kGy) or their combination. Treated samples were stored at 5°C and analyzed periodically for thiobarbituric acid reactive substances (TBARS), sensory characteristics and psychrotrophic bacterial counts during storage for 41 and 48 days for samples treated at 2 and 4.5 kGy respectively. Results demonstrated a significant benefit of the addition of herbal extracts to the ground beef prior to irradiation. All three extracts significantly (P<0.05) lowered the TBARS values and off-odor scores and significantly (P<0.05) increased color and acceptability scores in all samples with marjoram being the most effective. The combination treatment with herbal extracts plus irradiation resulted in extension of the shelf life of samples treated with 2 kGy by one week and samples treated with 4.5 kGy by two weeks, over that treated with irradiation alone. In conclusion, the addition of herbal extracts can minimize lipid oxidation, improve color and decrease off-odor production in irradiated ground beef.
Subject(s)
Antioxidants/pharmacology , Food Preservation/methods , Lipid Peroxidation/drug effects , Meat/analysis , Plant Preparations/pharmacology , Animals , Bacteria/drug effects , Cattle , Colony Count, Microbial , Color , Food Irradiation , Food Microbiology , Humans , Meat/microbiology , Odorants , Thiobarbituric Acid Reactive SubstancesABSTRACT
Radiobiological studies were carried out with three strains of Listeria monocytogenes . Resistance characteristics were determined under a variety of conditions. For one strain (CFPDC), the D10 values were 0.18, 0.21, and 0.44 kGy when subjected to gamma irradiation in phosphate buffer (pH 7.0), trypticase soy broth containing yeast extract (TSB-YE), and in poultry feed, respectively. For this strain, D10 values in poultry feed determined by using 60Co gamma rays or 10 MeV electrons as radiation sources were almost identical. D values for gamma irradiation of TSB-YE cultures were 0.21, 0.25, and 0.46 kGy for CFPDC, Scott A, and 81-861 strains, respectively.
