Food Microbiology and Safety Laboratory, Department of Agriculture, Food and Resource Sciences, University of Maryland Eastern Shore, Princess Anne, MD 21853, USA
Dr. Byungrok Rok Min
Food Microbiology and Safety Laboratory, Department of Agriculture, Food and Resource Sciences, University of Maryland Eastern Shore, Princess Anne, MD 21853, USA
Outbreaks of human gastroenteritis have been linked to the consumption of contaminated domestic and imported seafood. This study investigated the microbiological quality of seafood obtained from retail stores on the Eastern Shore of Maryland. A total of 440 samples of domestic and imported frozen shrimp, catfish and tilapia samples were analyzed for aerobic plate count (APC), total coliforms, Escherichia coli and seafood-borne-pathogens (Vibrio parahaemolyticus, Vibrio vulnificus, Salmonella, Campylobacter jejuni). The prevalence of APC, coliforms and E. coli positive samples was 100%, 43% and 9.3%, respectively. Approximately 3.2%, 1.4%, 28.9% and 3.6% of the samples were positive for V. parahaemolyticus, V. vulnificus, Salmonella and Campylobacter jejuni, respectively. The MPN/g ranges were 150–1100 MPN/g for vibrios, 10–1100 MPN/g for Salmonella and 93–460 MPN/g for C. jejuni in seafood, respectively. Comparing bacterial prevalence by type or source of seafood, the only significant difference identified was Salmonella-positive imported tilapia (33.3%) versus domestic tilapia (19.4%). The quantitative data on pathogen levels in the present study provide additional information for quantitative risk assessment not available in previous surveys. The findings of this study suggest the association of potential food safety hazards with domestic and imported seafood and warrant further large-scale studies and risk assessment.
This study evaluated the effects of feeding varying levels of dietary DL-methionine (MET) supplementation on breast meat (BM) quality of broilers of different sex. The 1-day-old, sexed chicks (Ross 708, 1552) were randomly allocated into four groups (each with 4 replicates) and were raised with diets supplemented with 0, 0.5, 1, or 2 g MET/kg of feed to a common weight (2.72 kg). Color, pH, drip loss (DL), water-holding capacity, moisture uptake, cooking yield (CY), texture, total antioxidant capacity (TAC), and lipid oxidation (LO) were determined using BM samples harvested 24 h postmortem. The male BM had higher redness, TAC, firmness, and toughness but lower yellowness (p < 0.01) than the female BM. In both sexes, birds fed 0.5 g/kg MET had lower DL (p < 0.01) than those fed 1 and 2 g/kg MET. For storage up to 3 days, MET suppressed LO in cooked BM (p < 0.01) and suppression increased as MET increased. CY for 1 and 2 g/kg MET were higher (p < 0.01; 79.04 and 78.60%, respectively) than CY for 0 and 0.5 g/kg MET (66.18 and 68.03%, respectively). These results suggest that MET supplementation at 1 g/kg or higher for broilers can improve oxidative stability, muscle functionality, and breast meat CY.
Two studies were conducted to determine the effects of dietary cholesterol (CHO) and cholesterol oxides (COPs) on the development of atherosclerosis and the changes in fatty acid and blood characteristics in rabbits. In the first study, forty male New Zealand white rabbits were divided into 5 groups and fed commercial rabbit chow with no added CHO or COPs, 1 g CHO, 0.9 g CHO + 0.1 g COPs, 0.8 g CHO + 0.2 g COPs, or 0.5 g CHO + 0.5 g COPs per kg diet. In the second study, 24 male New Zealand White rabbits were divided into 3 groups and fed a diet containing 2 g CHO, 1.6 g CHO + 0.4 g COPs, or 1.2 g CHO + 0.8 g COPs per kg diet. All diets induced atherosclerotic lesions in the rabbits’ ascending thoracic aorta. The serum CHO and triglyceride levels (p < 0.05) increased significantly with the increased levels of CHO in the diets. Dietary CHO or COPs did not influence high-density lipoprotein CHO levels. The ratio of saturated fatty acid to unsaturated fatty acid increased as the level of dietary CHO and COPs increased.
This study was designed to evaluate the effects of dietary supplemental DL-methionine (MET) on live performance and meat yield for broilers raised to a common weight. A total of 1552 one-day old Ross 708, sexed broilers were randomly distributed to 32 pens resulting in eight treatments (TRT) of four replicates with 44 male or 53 female/pen. A randomized complete block with a 2 × 4 (sex × 4 MET levels 0, 0.5, 1, and 2 g/kg) factorial arrangement of TRT was used. A common weight of 2400 g was approached by day 46 (1 and 2 g MET/kg feed) and day 48 (0 and 0.5 g MET/kg feed). Supplementation of MET at 1, and 2 g/kg had a lower (p < 0.01) feed conversion ratio (FCR) at day 46/48 than broilers fed 0.5 g MET/kg. Broilers without supplemental MET had the worst (p < 0.01) feed conversion and average daily gain (ADG) at day 46/48. Birds fed 0 g MET/kg of feed had lower (p < 0.05) whole eviscerated carcass without giblets (WOG), yield than birds fed 2 g MET/kg of feed. Additionally, birds fed 0 g MET/kg of feed had lower (p < 0.05) breast fillet and tender percent yields than birds fed supplemental MET. Elimination of MET from organic broiler diets resulted in reduced ADG, breast fillet yield and feed efficiency of meat yield of broilers raised to day 46/48. Reduction in MET supplementation below current levels reduced the efficiency of meat production of organic broilers raised to day 46/48.
Opportunities to capture anticipated niche markets for diverse populations continue to rise. Okra (Abelmoschus esculentus L.), considered a high-value crop, is rich in nutritional and medicinal properties; however, fresh okra is highly perishable. This study examined the effects of thermal pre-treatments and drying processes in combination on the nutritional quality of dried okra. The experiment consisted of two thermal treatments (steam-blanched and hot water-blanched, and the control) and three drying treatments (freeze-dried, hot air-dried, and infrared-dried). Okra was grown in black plastic mulch, harvested twice per week, and processed three times throughout the growing season. The study analyzed moisture content, water activity, phytonutrients, ascorbic acid, β-carotene, and antioxidant activities. No significant differences were observed in moisture content and water activity among the treatments. Significant differences were observed among treatments and harvest time for total phenolic and flavonoid contents and antioxidant activity. Notable differences in β-carotene content were observed across all treatments. Based on the findings, the steam-blanched freeze-dried treatment was the most effective preservation technique for maintaining the nutritional and functional quality of dried okra. Hot water-blanching, hot air-drying, and infrared-drying were the least effective for the development of a high-value, nutrient-dense dried okra value-added product.