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The effects of high-pressure treatments at various temperature-time combinations on the inactivation of spores of Clostridium botulinum type A strains 62-A and BS-A in phosphate buffer (0.067 M, pH 7.0) and in a crabmeat blend were investigated. The log unit reduction of strain 62-A spores increased significantly as the processing pressure increased from 417 to 827 MPa (from 60,000 to 120,000 lb/in2) at 75 degrees C. The reduction of BS-A and 62-A spores in either medium increased as processing temperatures increased from 60 to 75 degrees C and processing times increased from 5 to 15 or 20 min at a maximum pressure of 827 MPa. Approximately 2- and 3-log reductions of BS-A and 62-A spores, respectively, in phosphate buffer were obtained at the maximum pressure-maximum temperature combination of 827 MPa and 75 degrees C for a processing time of 20 min. Processing for 15 min at the maximum pressure-maximum temperature combination resulted in maximum reductions of 3.2 and 2.7 log units for BS-A and 62-A spores, respectively, in the crabmeat blend. Results obtained in this study indicate that the crabmeat blend did not protect BS-A and 62-A spores against inactivation by high-pressure processing.

Shelf life (onset of sensory spoilage) and the potential for toxin production by Clostridium botulinum type E in retail-type packages of fresh aquacultured salmon fillets packaged in high-barrier film bags under selected atmospheres (100% air, a modified atmosphere containing 75% CO 2 :25% N 2 , and vacuum) and stored under refrigeration (4°C) and temperature-abuse conditions (8 and 16°C) were investigated. Chemical spoilage indicators (trimethylamine and surface pH) and microbial populations were compared with sensory spoilage characteristics. Storage temperature influenced the time to onset of both sensory spoilage and toxin development in salmon fillets packaged in all atmospheres. The shelf life of fillets packaged in all atmospheres decreased with increase of storage temperature from 4 to 16°C. Trimethylamine content associated with the onset of spoilage for 100% air-packaged fillets increased as storage temperature increased. However, for modified-atmosphere-packaged fillets, the trimethylamine content associated with the onset of spoilage increased as storage temperature decreased from 8 to 4°C. Surface pH was not a good spoilage indicator for modified-atmosphere-packaged fillets. Toxin development preceded sensory spoilage at 16°C storage for fillets packaged in modified atmospheres. Toxin development coincided with sensory spoilage or was slightly delayed for the fillets packaged in all the atmospheres at 8°C storage. At 4°C none of the fillets packaged in either of the atmospheres developed toxin, even 20 days after spoilage as determined by sensory characteristics.

A multiple internal control was constructed to be used as an exogenously added control in reverse transcription polymerase chain reaction (RT-PCR) for pig cytokines. It consists of 5' and 3' primer sequences in the order of beta 2 microglobulin (beta 2-m), IL-1, IL-4, IL-6, IL-8, IL-2, IL-10, TNF-alpha, TNF-beta and IFN-gamma. Construction was accomplished by overlapping and extension PCR (OE-PCR) utilizing short oligonucleotides. The primers were designed to give two products of different sizes on co-amplification of control and target RNAs by RT-PCR in a single tube. This permits analysis of message for several cytokines using a single exogenously added competitive template. Incorporated endonuclease sites allow construct modification by oligonucleotide addition.

We investigated the shelf life of fresh Tilapia spp. fillets packaged in high-barrier film under both 100% air and a modified atmosphere (MA) of 75% CO 2 :25% N 2, and stored under refrigeration (4°C) and abuse temperatures (8 and 16°C). The chemical spoilage indicators trimethylamine, K-value, and surface pH, as well as microbial counts, were compared with the sensory characteristics of spoilage. For fillets packaged under 100% air, the shelf life was 9 to 13 days at a storage temperature of 4°C, but decreased to 3 to 6 days at 16°C. However, the shelf life of MA-packaged fillets stored at 4°C increased to >25 days when the lag phase and generation time of the bacteria were extended. MA packaged fillets stored under temperature-abuse conditions (8 and 16°C) had a shorter shelf life. The trimethylamine content associated with onset of sensory spoilage for MA packaged fillets increased as storage temperature increased and differed for each temperature. The surface pH and K-values of MA-packaged fillets were not good indicators of spoilage onset.

Fresh and 40-year-old pasteurized blue crab ( Callinectes sapidus ) meat was analyzed for proximate composition, mineral, heavy metal, and amino acid content and volatiles concentration and possible pesticide and herbicide residue levels. Both fresh and 40-year-old meat had similar proximate compositions. The 40-year-old crab meat contained high levels of iron, manganese, copper, and heavy metals compared to the fresh. Recovery of total amino acids was lower from the 40-year-old meat. Aspartic acid, glutamic acid, leucine, lysine, and arginine were the major protein amino acids of fresh and 40-year-old crab meat. The 40-year-old meat contained high concentrations of ethanol and trimethylamine compared to the fresh. No herbicide residues were detected in either of the products. Decomposition products of pesticide DDT were detected at very low levels only in the 40-year-old crab meat.

The compounds butylated hydroxyanisole (BHA); butylated hydroxytoluene (BHT); tert-butylhydroquinone (TBHQ); nor-dihydroguaiaretic acid (NDGA); 2', 4', 5'-trihydroxybutyrophenone (THBP); 8-hydroxyquinoline; isoamyl and isobutyl esters of gallic acid; ethyl, propyl, and butyl esters of p-hydroxybenzoic acid; thymol; 2-isopropylphenol; 2-tert-butylphenol; and 2-tert-butyl-4-methylphenol were tested for their antibotulinal activity in prereduced Thiotone-yeast extract-glucose (TYG) broth with and without hosphate buffer (0.05 M, pH 6.0 and 7.0). Isoamyl gallate, isobutyl gallate, propyl ester of p-hydroxybenzoic acid, NDGA, BHA, 8-hydroxyguinoline, and 2-tert-butylphenol were more inhibitory when phosphate buffer (pH 7.0(was added to prereduced TYG. The propyl and butyl esters of p-hydroxybenzoic acid and 2-isopropylphenol were more effective at pH 6.0 than at pH 7.0, whereas thymol and 8-hydroxyquinoline were slightly more active at pH 7.0 than at pH 6.0 NDGA at 50 μg/ml was the most effective compound tested for delaying growth and toxin production.

Increased awareness of the morbidity and mortality attributed to diarrheal disease among children under 5 years of age in developing countries has led to a variety of approaches aimed toward prevention. In this review, foods and food ingredients which appear to be most effective in prevention of diarrheal disease in infants are considered. The effect of each of the following potential food or food ingredient categories on the control or prevention of diarrheal disease is discussed: human milk components, antibodies, probiotics, and fermented foods.