J. Liston

Enzymatic transformation of PSP toxins in the littleneck clam (Protothacastaminea)

Stemming from investigations into the relationship between toxins produced by Gonyaulax sp. and accumulated in shellfish, we wish to report enzymatic transformations of the PSP toxins to decarbamoyl derivatives in the littleneck clam (Protothaca staminea). No toxin transformations were observed in either mussels (Mytilus edulis) or in butter clams (Saxidomus giganteus). In addition, littleneck clam samples from the natural environment contained predominantly the decarbamoyl derivatives, while other shellfish species collected from the same vicinity contained the previously reported PSP toxins.

EFFECTS OF INCUBATION TEMPERATURE ON THE SALT TOLERANCE OF SALMONELLA

Salt has been shown effective in preventing growth of salmonellae in foods. Many of the studies reported in the literature have been on the lethal action of high levels of salt as used in curing brines. Little information is available on the interaction of incubation temperature and low levels of salt on the growth of salmonellae. The growth of Salmonella heidelberg, Salmonella typhimurium, and Salmonella derby in nutrient broth containing 0 to 8% added NaCl (in 0.5 or 1% increments) has been tested by shake cultures at 8, 12, 22, and 37 C. In addition, S. heidelberg has also been tested in 0 to 9% added NaCl at 39, 41, 43, and 45 C. At 8 C, growth of S. heidelberg took place in 1 and 2% added NaCl; S. typhimurium increased in numbers in 1% added NaCl; and S. derby failed to increase. When incubated at 12 C, the three serotypes were all able to increase in numbers in the range of 0 to 4% NaCl. At 22 C, this range increased from 0 to a maximum of 5 to 8%. When incubated at 37 C, the organisms were able to ...

Fish protein for human foods

Fish contributes significantly to the world protein supply. The present fish catch, its losses in processing, and its consequent protein contribution to world needs are reviewed. Present protein losses are estimated to be considerable. The amount of fish protein reaching consumers can be increased by increasing the catch, by the development of fish cultivation, and by improving the efficiency of using the resource. Most of the recent work directed to this objective has concerned the manufacture of fish protein concentrate (FPC). Various forms of FPC, their preparation, safety, composition, nutritive value, acceptance, clinical application, and uses are reviewed. The potential for large‐scale development of FPC, both as a protein supplement and as a functional protein ingredient in sophisticated food formulation, is discussed.

Development and Evaluation of Oligonucleotide DNA Probes for Detection and Genotyping of Shiga-like Toxin Producing Escherichia coli

Use of antisense oligonucleotide probes (OP) for detection and genotyping of Shiga-like toxin producing Escherichia coli (SLTEC) was evaluated. Based on published deoxyribonucleic acid (DNA) sequences of the A subunits of Shiga-like toxin (SLT) I and II genes, three synthetic antisense OP were constructed (OP-1, -2 and -3). Their use for detection and genotyping of SLTEC was evaluated and the results were compared to those obtained using cloned toxin-gene probe fragments. Both the OP-1 and OP-2 hybridized with all 69 SLT-I and II producing strains. Furthermore, the OP-1 hybridized only with all 18 SLT-I-only producing strains, and the OP-2 hybridized only with all 48 SLT-II-only producing strains. OP-3, a pool of four OP, detected all SLTEC strains regardless of toxin genotype. None of the OP hybridized to any of the 91 SLT-negative strains. These results demonstrate the three OP to be unique reagents for SLTEC epidemiological studies.

Fishing and the fishing industry

Abstract World fish resources, fishing methods, and processing operations in the seafood industry are described. The fishery situation in developing countries (LDCs) is discussed, with particular reference to artisanal and other local fisheries, and examples are cited to illustrate the structure of the industry. Technology transfer from developed countries to LDCs is discussed and recommendations are presented for future technology transfer programs. It is concluded that an integrated complex of small projects with defined, attainable objectives and immediate impact on income and food supply of the LDC populations is likely to be more successful than large‐scale programs with little immediate payoff. A case study of fisheries in two developing countries, Thailand and Peru, and extensive tabulation of statistical data on catches, value of catch, and unit value of fish species groups for selected countries, with a discussion of the significance of the data, are presented in an appendix.