ISSN:
1750-3841
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
,
Process Engineering, Biotechnology, Nutrition Technology
Notes:
—Collections of freshwater crayfish were obtained from 22 sources representing the major commercial crayfishing areas in Louisiana, and analyzed for coliforms, Escherichia coli, fecal streptococci, coagulase-positive staphylococci, Salmonella and Clostridium botulinum type E. Growth patterns for E. coli, Staphylococcus aureus, Streptococcus faecalis and Salmonella typhimurium in raw and cooked crayfish flesh, and in a crayfish-containing commercial-type substrate were determined at 5, 25, and 37°C. C. botulinum type E toxin production was determined at intervals of storage in ice pack and at 5 and 30°C. Coliforms, E. coli, fecal streptococci, coagulase-positive staphylococci, Salmonella, and C. botulinum type E were found in 100, 92.6, 94.1, 3.0, and 0%, respectively, of the samples analyzed. Staphylococcus aureus and Salmonella typhimurium grew well in all three of the substrates at 25 and 37°C. Streptococcus faecalis and possibly E. coli showed suppressed growth in the raw flesh, but both grew well in cooked flesh and the commercial-type substrate. None of these four organisms grew at 5°C. C. botulinum type E produced toxin in all three of the substrates within 48 to 72 hours at 30°C and after 33 days at 5°C. Toxin was not produced at 56 days in ice-pack. The pH increased in the raw and cooked flesh, with extended storage time, to above 8.0 and the toxin became inactive. In the commercial-type substrate, the pH decreased to 5.7 and the toxin remained active. When the pH of the commercial-type substrate was adjusted to 8.5 with NaOH, the toxin was inactivated.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1365-2621.1969.tb10339.x
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