EFFECT OF HEADSPACE OXYGEN AND FILMS OF DIFFERENT OXYGEN TRANSMISSION RATE ON TOXIN PRODUCTION BY CLOSTRIDIUM BOTULINUM TYPE E IN RAINBOW TROUT FILLETS STORED UNDER MODIFIED ATMOSPHERES

2000 ◽  
Vol 20 (3) ◽  
pp. 157-175 ◽  
Author(s):  
ISABELLE DUFRESNE ◽  
JAMES P. SMITH ◽  
JIUN NI LIU ◽  
ILSEMARIE TARTE ◽  
BURKE BLANCHFIELD ◽  
...  
1995 ◽  
Vol 58 (8) ◽  
pp. 863-866 ◽  
Author(s):  
DONNA M. GARREN ◽  
MARK A. HARRISON ◽  
YAO-WEN HUANG

Rainbow trout (Oncorhynchus mykiss) were inoculated with 3 to 4 1og10 spores per g of fish of a mixed pool of four strains of Clostridium botulinum type E (Beluga, Minnesota, G21-5, and 070). The trout were vacuum-skin packaged with either oxygen-barrier or oxygen-permeable films. Trout packaged with oxygen-permeable film were stored at 4°C for 21 days, while trout packaged with oxygen-barrier film were stored either at 4°C for 21 days or at 10°C for 15 days. Storage at 10°C was used to simulate commercial temperature abuse. Clostridium botulinum outgrowth was determined by a most probable-number (MPN) method using (tryptone peptone yeast extract glucose trypsin) anaerobic broth. Toxin production was evaluated using a mouse bioassay. Psychrotrophic and anaerobic populations increased with time regardless of packaging type. After 6 days at l0°C, botulinum toxin was detected in the packaged trout; however, the fish was noticeably spoiled before that time. No botulinum toxin was detected in trout packaged with either barrier or permeable films and stored at 4°C for 21 days, although the product was considered spoiled by day 12.


1987 ◽  
Vol 50 (3) ◽  
pp. 212-217 ◽  
Author(s):  
S. L. CUPPETT ◽  
J. I. GRAY ◽  
J. J. PESTKA ◽  
A. M. BOOREN ◽  
J. F. PRICE ◽  
...  

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.


1997 ◽  
Vol 60 (11) ◽  
pp. 1358-1363 ◽  
Author(s):  
PING CAI ◽  
MARK A. HARRISON ◽  
YAO-WEN HUANG ◽  
JUAN L. SILVA

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.


1987 ◽  
Vol 50 (4) ◽  
pp. 330-336 ◽  
Author(s):  
GENERO W. GARCIA ◽  
CONSTANTIN GENIGEORGIS ◽  
SEPPO LINDROTH

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.


1997 ◽  
Vol 60 (9) ◽  
pp. 1055-1063 ◽  
Author(s):  
N. R. REDDY ◽  
H. M. SOLOMON ◽  
H. YEP ◽  
M. G. ROMAN ◽  
E. J. RHODEHAMEL

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% CO2:25% N2, 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.


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