Effect of Sugar and Low-Dose Irradiation on Toxin Production by Clostridium botulinum in Comminuted Bacon

1986 ◽  
Vol 49 (2) ◽  
pp. 112-116 ◽  
Author(s):  
C. N. HUHTANEN ◽  
J. SHIEH ◽  
E. WIERBICKI ◽  
L. ZAIKA ◽  
R. K. JENKINS ◽  
...  

Comminuted bacon, processed to contain target levels of 40 μg NaNO2/g and 0, 0.25 or 0.75% sucrose or 0.75% glucose, was inoculated with a mixture of spores of 20 strains of Clostridium botulinum (400 spores per g) and was canned under vacuum. Portions were irradiated using 137Cs at doses of 0, 0.19, 0.38, 0.75, 1.12 and 1.5 Mrad. Cans were incubated for 1, 2, 4 or 8 wk at 30°C. Some cans of nonirradiated bacon without or with 0.25% sucrose became toxic in 2 wk; with 0.75% sucrose, toxin production was delayed to 8 wk. Bacon irradiated at 0.75 Mrad, made with or without sucrose, became toxic in 2 to 4 wk, whereas most cans of bacon irradiated at 1.5 Mrad remained toxin-free for the 8-wk incubation period. A comparison of bacon made with 0.75% sucrose or glucose showed no difference between the sugars in the rates of toxin production by C. botulinum in irradiated cans of bacon. Irradiation at 0.19 Mrad increased the rate of toxin formation over nonirradiated bacon in sugar-containing (0.75%) bacon, but had no effect in sugar-free bacon. The pH of nonirradiated bacon containing 0.75% glucose or sucrose decreased from pH 6.12 and 6.11, respectively, to pH 5.63 and 5.67 after 8 wk of incubation at 30°C. The titratable acidity showed a concurrent increase. The pH and titratable acidity of bacon irradiated at 0.19 Mrad or higher showed no changes.

1991 ◽  
Vol 54 (8) ◽  
pp. 588-592 ◽  
Author(s):  
ANNE D. LAMBERT ◽  
JAMES P. SMITH ◽  
KAREN L. DODDS

The effects of five initial levels of CO2 (15, 30, 45, 60, and 75%) and three irradiation doses (0, 0.5, and 1.0 kGy) on toxin production by Clostridium botulinum in inoculated fresh pork were studied using factorial design experiments. Headspace CO2 levels increased in all samples during storage at 15°C. In most treatments, spoilage preceded toxigenesis. Toxin production occurred faster in samples initially packaged with 15 to 30% of CO2 while higher levels of CO2 (45–75%) delayed toxin production. Low-dose irradiation delayed toxin production at all levels of CO2 in the package headspace. Contrary to expectations, including a CO2 absorbent in the package enhanced toxin production by C. botulinum. This was attributed to production of H2 by the CO2 absorbent, possibly resulting in a decrease in the oxido-reduction potential of the meat.


1991 ◽  
Vol 54 (12) ◽  
pp. 939-944 ◽  
Author(s):  
ANNE D. LAMBERT ◽  
JAMES P. SMITH ◽  
KAREN L. DODDS

The effects of irradiation, initial O2, initial CO2 and the presence of an O2 and CO2 absorbent on toxin production by Clostridium botulinum in inoculated pork stored at 15°C were studied using a factorial experiment. Toxin production occurred faster in samples initially packaged with 20% O2, compared to samples packaged with 100% N2. The presence of CO2 in the package headspace was not a significant factor affecting time until toxin detection. Irradiation was significant in delaying the time until toxin detection in samples initially packaged with 20% O2 but not in other treatments. Sensory rejection, based primarily on discoloration, occurred within 7 to 14 d, irrespective of treatment. All samples were spoiled before they became toxic.


2017 ◽  
Vol 80 (8) ◽  
pp. 1252-1258 ◽  
Author(s):  
Max C. Golden ◽  
Brandon J. Wanless ◽  
Jairus R. D. David ◽  
D. Scott Lineback ◽  
Ryan J. Talley ◽  
...  

ABSTRACT Clostridium botulinum is a foreseeable biological hazard in prepared refrigerated meals that needs to be addressed in food safety plans. The objective of this study was to evaluate the effect of product composition and storage temperature on the inhibition of botulinum toxin formation in nine experimental meals (meat, vegetable, or carbohydrate based). Treatments were inoculated with proteolytic C. botulinum, vacuum packaged, cooked at 90°C for 10 min, and assayed for botulinum toxin in samples stored at 25°C for up to 96 h for phase 1, or at 25°C for 12 h and then transferred to 12.5°C for up to 12 and 6 weeks in phases 1 and 2, respectively. For phase 1, none of the treatments (equilibrated pH 5.8) supported toxin production when stored at 25°C for 48 h, but toxin production was observed in all treatments at 72 h. For the remaining experiments with storage at 12.5°C, toxin production was dependent on equilibrated pH, storage time, and growth of indigenous spoilage microorganisms. In phase 1, no gross spoilage and no botulinum toxin was detected for any treatment (pH ≤5.8) stored at 12.5°C for 12 weeks. In phase 2, gross spoilage varied by commodity, with the brussels sprouts meal with pH 6.5 showing the most rapid spoilage within 2 weeks and botulinum toxin detected at 5 and 6 weeks for the control and cultured celery juice treatments, respectively. In contrast, spoilage microbes decreased the pH of a pH 5.9 beef treatment by 1.0 unit, potentially inhibiting C. botulinum through 6 weeks at 12.5°C. None of the other treatments with pH 5.8 or below supported toxin production or spoilage. This study provides validation for preventive controls in refrigerated meals. These include equilibrated product pH and storage temperature and time to inhibit toxin formation by proteolytic C. botulinum, but the impact of indigenous microflora on safety and interpretation of challenge studies is also highlighted.


1995 ◽  
Vol 58 (6) ◽  
pp. 624-627 ◽  
Author(s):  
RUTH L. PETRAN ◽  
WILLIAM H. SPERBER ◽  
ARTHUR B. DAVIS

The potential for growth and toxin production by Clostridium botulinum spores was investigated in samples of fresh-cut romaine lettuce and shredded cabbage packaged in vented and nonvented flexible pouches at storage temperatures of 4.4, 12.7, and 21°C for up to 28 days. One hundred grams of cut, washed romaine lettuce and cabbage were placed in polyester bags. Approximately 104 heat-shocked spores were added per package. Before sealing, half the packages were vented. No toxin was detected with either storage method at 4.4 and 12.7°C. In nonvented pouches of romaine lettuce at 21°C, spores grew and produced toxin after 14 days. Romaine samples at 21°C in vented pouches became toxic after 21 days, indicating formation of anaerobic microenvironments within the pouches. In nonvented packages of cabbage at 21°C, toxin was detected after 7 days. All toxin-positive samples were judged to be inedible prior to toxin detection.


1992 ◽  
Vol 55 (1) ◽  
pp. 23-27 ◽  
Author(s):  
R. C. WHITING ◽  
K. A. NAFTULIN

A series of experiments was conducted to determine growth and toxin formation by proteolytic strains of Clostridium botulinum in broth media that have known pH values (5–7), NaCl concentrations (0–4%), and controlled oxygen-nitrogen atmospheres. Lower pH and higher NaCl levels inhibited growth and toxin production by vegetative cells, but 15% oxygen in the headspace was insufficient for inhibition in all media. When spores were used as inocula and the tubes were gas flushed, outgrowth and toxin production generally occurred only under a 1% or less oxygen atmosphere. Occurrence of growth and toxin was favored by high pH and low NaCl levels and was related to spore inoculum size. Spores were also inoculated into a mixed fermenter with controlled oxygen levels in the headspace. Times to measurable turbidity increased with greater oxygen levels from 36 h at 0.005% O2 to 109 h at 0.7% O2; however, growth rates were unaffected by headspace oxygen levels. No toxin was observed with 0.9% O2, further demonstrating that the critical level of oxygen for germination and growth is approximately 1%.


1990 ◽  
Vol 53 (12) ◽  
pp. 1025-1032 ◽  
Author(s):  
HIROYUKI IMAI ◽  
KATSUNORI OSHITA ◽  
HIKOTAKA HASHIMOTO ◽  
DANJI FUKUSHIMA

The objective of this study was to evaluate the safety of five different “tsuyu” (Japanese noodle soups) and the effects of incubation temperature, salt concentration, and pH by pursuing the fate of Clostridium botulinum types A and B spores inoculated into them. C. botulinum did not produce toxin in three concentrated types (pH 5.0–5.3, NaCl 8–12%) of “tsuyu” within 3 months at 30°C and in two ready-to-use types (pH 4.83–4.92, NaCl 3.95–4.05) within 6 months at 20 and 30°C. In addition to the “tsuyu” products, positive controls of ready-to-use “tsuyu” with pH-salt combinations adjusted with a sterile NaOH solution to pH 7.0, 6.5, 6.0, and 5.5 and diluted with sterile distilled water to 3, 2, and 1% salt concentrations were included in this study. Growth and toxin production by C. botulinum in positive controls were dependent upon incubation temperature, pH, and salt concentration. That is, no botulinum toxin would occur in “tsuyu” with 4% salt at pH below 6.5 at 20°C; with 1% salt at pH below 5.0 at 30°C; 2 or 3% salt at pH below 5.5 at 30°C; 4% salt at pH below 6.0 incubated at 30°C, even if contaminated with the spores.


1979 ◽  
Vol 42 (11) ◽  
pp. 858-861 ◽  
Author(s):  
M. C. ROBACH ◽  
M. D. PIERSON

Butylated hydroxyanisole (BHA) was inhibitory to growth of three proteolytic strains of Clostridium botulinum in prereduced thiotone yeast-extract glucose medium (TYG) (pH 7.0) at 37 C. There was outgrowth and toxin production by strain 10755A spores when 25 ppm of BHA was present in the medium, whereas growth was inhibited by 50 ppm of BHA. Strains 62A and 213B were inhibited by 25 ppm of BHA throughout an incubation period of 7 days. Butylated hydroxytoluene (BHT) and propyl gallate (PG) were less effective in inhibiting outgrowth of C. botulinum spores than was BHA. Spore outgrowth and toxin production were inhibited in the presence of 200 ppm of BHT in the TYG. PG exhibited the least inhibitory activity of the antioxidants tested. None of the levels (25 to 200 ppm) of PG tested delayed outgrowth or toxin formation for more than 24 h.


1985 ◽  
Vol 48 (11) ◽  
pp. 971-975 ◽  
Author(s):  
G. A. PELROY ◽  
A. SCHERER ◽  
M. E. PETERSON ◽  
R. PARANJPYE ◽  
M. W. EKLUND

Whitefish steaks were brined in NaCl, KCl, or equimolar NaCl:KCl to contain similar chloride ion concentration and inoculated intramuscularly with 10 or 100 spores of Clostridium botulinum type E per gram of fish. Steaks were then heated in a simulated (i.e., without smoke) hot-smoke process to internal temperatures of 62.8° to 76.7°C (145°–170°F) for the final 30 min of a 2- to 3-h process, packaged under vacuum in oxygen-impermeable film, and stored at abuse temperature of 25°C. During 7 d of storage, toxin production was inhibited in steaks containing more than 0.66 ionic strength NaCl, 0.64 KCl, or 0.71 equimolar NaCl:KCl. The results indicate that it is feasible to substitute KCl for NaCl in hot-process smoked fish for inhibition of outgrowth and toxin production by Clostridium botulinum type E.


2017 ◽  
Vol 80 (8) ◽  
pp. 1259-1265 ◽  
Author(s):  
Max C. Golden ◽  
Brandon J. Wanless ◽  
Jairus R. D. David ◽  
Bala Kottapalli ◽  
D. Scott Lineback ◽  
...  

ABSTRACTClostridium botulinum may be of concern in prepared refrigerated meals, for which strict cold chain management cannot be guaranteed. This study evaluated the effect of temperature, product composition, and cultured celery juice powder (CCJP) as a source of nitrite on the inhibition of botulinum toxin formation in two experimental (meat- and vegetable-based) prepared meals. Data obtained from the challenge study were compared with a published mathematical model to determine whether the model is fail-safe with regard to the tested meals. Treatments were inoculated with proteolytic C. botulinum, vacuum packaged, cooked at 90°C for 10 min, and assayed for botulinum toxin at appropriate intervals in samples stored at 10, 15, or 20°C for up to 8 weeks. None of the treatments stored at 10°C for 8 weeks supported toxin production by proteolytic C. botulinum. The addition of CCJP delayed toxin production by 1 and 3 weeks in cauliflower potatoes and in Dijon pork, respectively, stored at 15°C. Toxin production was delayed by 1 week at 20°C when CCJP was added to the cauliflower potatoes. This study found that the predictive model was fail-safe but was overly conservative for the experimental meals described. Finally, this study confirms that product composition, the addition of nitrite via CCJP, storage time, and temperature play important roles in the inhibition of toxin formation by proteolytic C. botulinum.


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