The shelf life of seafood under current icing and refrigerated storage conditions ranges from 2 to 14 d, depending on species, harvest location, and season. Elevated carbon dioxide levels in modified atmosphere packaging (MAP) has been shown to inhibit the normal spoilage flora of seafood and double or triple shelf life. The threat of botulism, due to the presence of nonproteolytic psychyrotrophic Clostridium botulinum types B, E, and F, has been reason for caution in expanding this technology. This article examines the safety of MAP seafood through analysis and comparison of raw materials, research methodologies, quality indices, treatment, and packaging options.

Cut romaine lettuce, packaged under modified atmosphere, was subjected to 0.15 and 0.35 kGy gamma irradiation. Irradiation at 0.35 kGy decreased aerobic plate counts by 1.5 logs and yeast and mold counts by 1 log; these differences were maintained through the 22-d storage. Irradiation at 0.15 kGy caused smaller reductions in microbial counts. A decrease in headspace CO 2 was observed in the 0.35-kGy-treated lettuce, although CO 2 concentrations increased in all samples with storage. O 2 concentration was not affected by irradiation. Ten percent loss in firmness was observed at 0.35 kGy, while other sensory attributes such as color, generation of off-flavor, and appearance of visual defects were not affected.

The effects of 0.5 and 1.0 kGy gamma irradiation on microbial and sensory characteristics of diced celery were compared to conventional treatments such as acidification, blanching, and chlorination. Aerobic plate counts for the irradiated celery did not exceed 10 7 CFU/g, in contrast, the acidified, blanched, chlorinated, and control samples surpassed aerobic microbial counts of 10 8 CFU/g in 22, 19, 12, and 8 d, respectively. Importantly, the 1.0-kGy treatment eliminated inoculated Listeria monocytogenes and E. coli. While the acidified and blanched samples had significantly different sensory profiles compared to the other treatments, the irradiated samples maintained their color, texture, and aroma longer and were preferred in the sensory tests. The sensory shelf life of the 1.0-kGy-treated celery was 29 d compared to 22 d for the control, chlorinated, and 0.5 kGy, and 15 d for the acidified and blanched celery.

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Cilantro (Coriandrum sativum) inoculated with Escherichia coli O157:H7 at levels approximating 10(7) CFU/g was dipped in 200 ppm chlorine solution followed by low-dose gamma irradiation. Samples were plated on tryptic soy agar containing 50 microg/ml nalidixic acid (TSAN) as well as TSAN plates with two 7-ml layers of basal yeast extract agar (TSAN-TAL). Levels of E. coli O157:H7 recovered from both types of media were determined over 11 days. Chlorination alone reduced counts by just over 1.0 log cycle, whereas irradiation at 1.05 kGy resulted in a 6.7-log reduction, and a combination of irradiation and chlorination reduced counts more than 7 log cycles. Trained panels performed analytical sensory tests at time intervals for 14 days to detect changes in yellowing, tip burn, browning, black rot, sliminess, off-aroma, and off-flavor. Sensory tests found no significant differences among attributes over time or dose in samples irradiated at 1.08 to 3.85 kGy. This study showed that combination treatments of chlorination and low-dose irradiation can significantly reduce levels of E. coli O157:H7 in fresh cilantro while maintaining product quality.

In an effort to enhance the utilization of sheep (Ovis dries) meat, this study was designed to isolate and identify compounds from ovine subcutaneous adipose tissue (Panniculus adiposus) which contribute to the characteristic flavor of the meat. Samples were taken from three Suffolk wether lambs and subsequently steam deodorized, extracted, fractionated, and analyzed. Olfactory and gas chromatographic (GC) analyses confirmed that the bulk of the flavor volatile compounds were in the neutral fraction, some in the acidic fraction, but little or none were detected in the basic fraction. Gas chromatographic-mass spectrometric (GC-MS) analysis of the neutral fraction resulted in the identification of 51 compounds: 26 aldehydes, 12 ketones, 6 lactones, 4 alcohols, and 3 cyclics. Thirty-nine of these compounds are being reported for the first time as constituents (some tentative) of ovine fat volatiles. Although no single neutral fraction compound identified could be shown to be primarily responsible for lamb/mutton flavor, 14 (10 aldehydes, 3 ketones, and 1 lactone) are suggested as important contributors to the overall flavor quality.Generally, animal meat products are well-balanced nutritionally in energy, protein, minerals, and vitamins, and their palatability makes them a desirable food source for man. Thus, the decreasing trend in the utilization of sheep meat as a foodstuff deserves immediate attention in this age of critical world food supplies (USDA, 1976). From all reports, it appears that the distinctive flavor of sheep meat (Wasserman and Talley, 1968), especially that from older animals, is somewhat less acceptable and thus responsible for its low consumption rate by U.S. consumers (Ziegler and Daly, 1968).Generally, the lipid-soluble flavor components are the most important (Sink, 1973) and many factors contribute to their expression (Sink and Caporaso, 1977). Although the lipid-soluble compounds responsible for the characteristic sheep meat (lamb or mutton) flavor are yet to be completely inventoried, current interest has focused attention on the acid fraction volatiles (Wong et al., 1975a,b).It was the purpose of this study to identify the volatile neutral fraction flavor components from ovine adipose tissue. EXPERIMENTAL PROCEDURESSampling. Following standard exsanguination and chilling (3 °C) procedures, subcutaneous fat (Panniculus adiposus) samples (300 g) were taken from three castrate-male (wether) Suffolks (Ovis aries) raised under similar management conditions and nutritional regimes.Each sample was subsequently ground through a 3-mm plate, placed under nitrogen in an impermeable container, and frozen at -29 °C. The frozen samples were then gently melted (50 °C) and filtered through several layers of cheesecloth to separate the liquid fat from the tissue residue. Olfactory evaluation indicated the liquid fat did possess the distinctive sheep meat (lamb/mutton) character.Steam Deodorization. One hundred grams of liquid fat was transferred into the 500-mL round-bottom flask

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