STUDIES ON THE IRRADIATION OF MICROORGANISMS IN RELATION TO FOOD PRESERVATION: II. IRRADIATION RESISTANT MUTANTS

1961 ◽  
Vol 7 (2) ◽  
pp. 207-215 ◽  
Author(s):  
I. E. Erdman ◽  
F. S. Thatcher ◽  
K. F. MacQueen
Keyword(s):  
Clostridium Botulinum ◽  
Toxin Production ◽  
Food Preservation ◽  
Toxic Substances ◽  
Salmonella Gallinarum ◽  
E Coli ◽  
Development Of Resistance ◽  
Botulinum Type ◽  
Resistant Mutants ◽  
Radical Interaction

Using a Co60 source, repeated irradiation of survivors of bacterial cultures at a level initially destroying a high proportion of cells gave rise to strains which were more resistant to irradiation than the original cultures. Development of resistance was shown in single strains of Escherichia coli, Streptococcus faecalis, and Clostridium botulinum type A, and in one of three strains of Staphylococcus aureus, but not in two strains of C. botulinum type E nor in Salmonella gallinarum. Changes were noted in phage patterns of the staphylococci, biochemical characteristics of E. coli, and toxin production of C. botulinum in response to repeated irradiation.Irradiation of parent and resistant cultures at −78 °C did not change their comparative resistance, though each was afforded some protection at this temperature. These findings suggest that the induced resistance is an expression of resistance to the primary effect of irradiation and not to possible toxic substances formed by free-radical interaction.

Effect of Salt Level and Nitrite on Toxin Production by Clostridium botulinum Type E Spores in Smoked Great Lakes Whitefish1

1987 ◽  
Vol 50 (3) ◽  
pp. 212-217 ◽  
Author(s):  
S. L. CUPPETT ◽  
J. I. GRAY ◽  
J. J. PESTKA ◽  
A. M. BOOREN ◽  
J. F. PRICE ◽  
...  
Keyword(s):  
Great Lakes ◽  
Water Activity ◽  
Salt Concentration ◽  
Clostridium Botulinum ◽  
Toxin Production ◽  
Water Phase ◽  
Salt Level ◽  
Botulinum Type ◽  
Clostridium Botulinum Type E ◽  
Average Water

The effect of salt level and nitrite on botulinal safety of smoked whitefish was investigated. An average water-phase (wp) salt concentration of 4.4% inhibited outgrowth of Clostridium botulinum type E spores (103 spores/g) for over 35 d in temperature-abused (27°C) smoked whitefish. Incorporation of nitrite (220 mg/kg) during brining to the smoked salted (4.4%, wp) whitefish inhibited toxin production for 56 d at 27°C. An average salt concentration of 6.2% (wp), with or without nitrite, totally inhibited toxin production for the duration of the study (83 d). The effect of pH and water activity in temperature-abused smoked whitefish as a means of controlling toxin production by C. botulinum type E spores was evaluated.

Toxin Production by Clostridium botulinum Type E in Packaged Channel Catfish

1997 ◽  
Vol 60 (11) ◽  
pp. 1358-1363 ◽  
Author(s):  
PING CAI ◽  
MARK A. HARRISON ◽  
YAO-WEN HUANG ◽  
JUAN L. SILVA
Keyword(s):  
Channel Catfish ◽  
Clostridium Botulinum ◽  
Modified Atmosphere Packaging ◽  
Toxin Production ◽  
Storage Conditions ◽  
Mouse Bioassay ◽  
Modified Atmosphere ◽  
Oxygen Barrier ◽  
Botulinum Type ◽  
Clostridium Botulinum Type E

Channel catfish were inoculated with 3 to 4 log spores/g of a mixed pool of four strains of C. botulinum type E (Beluga, Minnesota, G21-5, and 070) and were packaged with an oxygen-permeable overwrap, in an oxygen-barrier bag with a modified atmosphere of CO2-N2 (80:20) or in a master bag with the same modified atmosphere. Packaged fish were stored at either 4°C and sampled at intervals over 30 days or at 10°C and sampled at intervals over 12 days. An additional master bag treatment in which overwrap-packaged catfish was stored first at 4°C, then removed from the master bags and stored at 10°C, was sampled at intervals over 18 days. Toxin production was evaluated using the mouse bioassay. Aerobic psychrotrophic and anaerobic populations were enumerated, and product spoilage characteristics were noted. Under abusive storage conditions of 10°C, there was no difference among the potential for toxin production in the packaged fish, with botulinum toxin detected on fish from each package type by day 6. At 4°C, toxin production was detected on day 9 in the overwrapped packages, while it was on day 18 in the modified atmosphere packaging. No toxin was found in the master bags held continually at 4°C. Toxin was detected on day 18 from samples initially held at 4°C in the master bag and subsequently held at 10°C. Spoilage preceded toxin production for samples stored at 4°C for each type of packaging. At 10°C, spoilage and toxin detection times coincided.

SOME OBSERVATIONS OF THE EFFECT OF FILTRATES OF SEVERAL REPRESENTATIVE CONCOMITANT BACTERIA ON CLOSTRIDIUM BOTULINUM TYPE A

1961 ◽  
Vol 7 (4) ◽  
pp. 633-639 ◽  
Author(s):  
F. D. Crisley ◽  
G. E. Helz
Keyword(s):  
Escherichia Coli ◽  
Phosphate Buffer ◽  
Clostridium Botulinum ◽  
Type A ◽  
Complete Medium ◽  
Clostridium Sporogenes ◽  
Streptococcus Faecalis ◽  
E Coli ◽  
Botulinum Type ◽  
High Concentrations

Filtrates of growing cultures of Bacillus sphacricus, Clostridium sporogenes, Escherichia coli, and Streptococcus faecalis inhibited germination of spores of Clostridium botulinum type A. Of the four filtrates only that of E. coli was inactive at low (1:8) concentrations, and all were inhibitory at high (1:2) levels. Only filtrates of B. sphaericus and C. sporogenes affected lysis (increased) of washed cells of C. botulinum, and only S. faecalis filtrate altered botulinal toxigenicity in a complete medium. S. faecalis filtrate enhanced the final toxicity when present in high concentrations in the presence of phosphate buffer.

Risk of Growth and Toxin Production by Clostridium botulinum Nonproteolytic Types B, E, and F in Salmon Fillets Stored Under Modified Atmospheres at Low and Abused Temperatures

1987 ◽  
Vol 50 (4) ◽  
pp. 330-336 ◽  
Author(s):  
GENERO W. GARCIA ◽  
CONSTANTIN GENIGEORGIS ◽  
SEPPO LINDROTH
Keyword(s):  
Clostridium Botulinum ◽  
Storage Time ◽  
Toxin Production ◽  
Lag Phase ◽  
Type B ◽  
Inoculum Level ◽  
Modified Atmospheres ◽  
Botulinum Type ◽  
Best Fit ◽  
Design Experiments

In factorial design experiments we inoculated fresh salmon fillets with a spore pool of 13 nonproteolytic strains of Clostridium botulinum type B, E, and F at 6 levels (10−1 to 104/50 g of fillet), and incubated at 1, 4, 8, 12 and 30°C under modified atmospheres (MA) of vacuum, 100% CO2 and 70% CO2 + 30% air for up to 60 d. The earliest time we detected toxin in the fillets at 30, 12 and 8°C, irrespective of MA, was after 1, 3–9 and 6–12 d of storage and required 100–103, 101–103, 101–102 spores/fillet. The probability (P) of toxin production was significantly (P<0.05) affected by temperature (T), MA storage time (ST), MA × T, MA × ST and T × ST. Only type B toxin was detected in the toxic fillets. No toxin was detected in fillets stored at 4°C for up to 60 d. Toxin detection coincided with spoilage at 30°C, but preceded spoilage at 8 and 12°C, and followed spoilage at 4°C. Using linear and logistic regression analysis, best fit equations were derived relating the length of the lag phase and P of toxin production to T, ST, MA and spore inoculum level.

Growth and Toxin Production by Clostridium botulinum in Sauteed Onions

1986 ◽  
Vol 49 (8) ◽  
pp. 618-620 ◽  
Author(s):  
HAIM M. SOLOMON ◽  
DONALD A. KAUTTER
Keyword(s):  
Clostridium Botulinum ◽  
Culture Media ◽  
Type A ◽  
Toxin Production ◽  
High Inoculum ◽  
Botulinum Type ◽  
Large Outbreak

In October, 1983, sauteed onions in “patty-melt” sandwiches were epidemiologically responsible for a large outbreak of botulism in Peoria, Illinois. Spores of strains of Clostridium botulinum type A, recovered from Spanish onions or from patients who consumed sauteed onions, produced high toxin titers within 48 h from 2 spores/g of onions when experimentally inoculated into sauteed onions. Laboratory strains of C. botulinum type A which normally produce high-titered toxin in culture media yielded very low toxin titers and required 3 to 4 d and an extremely high inoculum of spores/g of onions. Five strains of C. botulinum type A were isolated from 75 raw onions obtained from the Peoria restaurant where the outbreak occurred.

Growth and Toxin Production by Clostridium botulinum in Sliced Raw Potatoes Under Vacuum With and Without Sulfite

1994 ◽  
Vol 57 (10) ◽  
pp. 878-881 ◽  
Author(s):  
HAIM M. SOLOMON ◽  
E. JEFFERY RHODEHAMEL ◽  
DONALD A. KAUTTER
Keyword(s):  
Sensory Evaluation ◽  
Clostridium Botulinum ◽  
Room Temperature ◽  
Type A ◽  
Toxin Production ◽  
Inoculum Size ◽  
Consumer Acceptability ◽  
Human Consumption ◽  
Type B ◽  
Botulinum Type

The ability of Clostridium botulinum type A or B spores to grow and produce toxin in fresh raw potatoes under vacuum with or without sulfite at 22°C was investigated. Fresh, peeled, sliced potatoes, untreated or dipped for 2 min in sulfite (NaHSO3) and drained, were surface-inoculated at several levels with a mixture of C. botulinum spores, either type A or B, and placed in oxygen-impermeable bags (200 g/bag) that were then vacuum-sealed and incubated at room temperature (22°C). Toxicity was tested on days 0, 3, 4, 5 and 6. After incubation, the potatoes were blended and centrifuged, and the millipore-filtered supernatant fluid was injected intraperitoneally into mice. Sensory evaluation, except taste, was also performed. Potatoes inoculated with C. botulinum type A spores, but untreated with NaHSO3 became toxic in 3 days, which coincided with the sensory evaluation, “Unfit for human consumption.” However, despite inoculum size or residual SO2 levels, potatoes treated with NaHSO3 appeared acceptable for human consumption through day 6, even though they were toxic after 4 days of incubation. Toxicity from type B spores occurred later and in fewer test samples than type A. Again, the potatoes appeared acceptable but were toxic. Thus, although NaHSO3 markedly extended the consumer acceptability of peeled, sliced, raw potatoes at the abuse temperature, it did not inhibit outgrowth and toxin production by C. botulinum under these same conditions.

Sign in / Sign up

Export Citation Format

Share Document