Clostridium botulinum toxin development in refrigerated reduced oxygen packaged Atlantic croaker (Micropogonias undulatus)

The purpose of this study was to determine the effects of storage temperature and film oxygen transmission rate (OTR) on toxin development by Clostridium botulinum in refrigerated raw vacuum packaged croaker fillets, and to determine if toxin development precedes microbiological and/or organoleptic spoilage. Raw croaker fillets were vacuum packaged in oxygen-permeable films (OTR of 10,000 cc/m2/24hr or 3,000 cc/m2/24hr) and stored at either 4ºC or 10ºC. Type 83F, 17 Type B, Beluga, Minnesota, and Alaska nonproteolytic strains of C. botulinum were used to inoculate fish prior to vacuum packaging. At both temperatures, microbial spoilage preceded toxin production in fillets vacuum packaged in both film types. At 4ºC microbial spoilage occurred after approximately 7 days for fillets vacuum packaged in the 10,000 cc/m2/24hr OTR film and after 8 days for fillets vacuum packaged in the 3,000 cc/m2/24hr OTR film. However, toxin was not detected until day 8. At 10ºC microbial spoilage occurred after approximately 3 days for fillets vacuum packaged in the 10,000 cc/m2/24hr OTR film, while toxin production occurred on day 5. For fillets vacuum packaged in the 3,000 cc/m2/24hr OTR film microbial spoilage occurred after 4 days. However toxin production did not occur until day 6. In contrast, at both temperatures toxin production preceded or coincided with organoleptic spoilage in fillets vacuum packaged in both film types. At 4ºC organoleptic spoilage occurred after 10 days for fillets packaged in the 10,000 cc/m2/24hr OTR film and after 9 days in the 3,000 cc/m2/24hr OTR film, while toxin production occurred on day 8. At 10ºC organoleptic spoilage occurred after 6 days for fillets packaged in the 10,000 cc/m2/24hr OTR film, and toxin was detected on day 5. For fillets packaged in the 3,000 cc/m2/24hr OTR film and stored at 10ºC, organoleptic spoilage occurred after 6 days, while toxin production occurred on day 6. Although toxin production preceded or coincided with organoleptic spoilage in both film types, this may have been because samples were presented on ice, which could have masked potential odors. This study shows that there are not significant differences between these film types when it comes to microbial and organoleptic spoilage. Therefore lower OTR films, such as 3,000 cc/m2/24hr film, may be used to vacuum package Atlantic croaker.

Name thesis:degree_name

Master of Science in Life Sciences

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Food Science and Technology

Department dc:contributor.department

Food Science and Technology

Grantor dc:publisher

Virginia Tech

Year dc:date.issued

2007

Author dc:creator

• Rheinhart, Courtney Elizabeth

Chair dc:contributor.committeechair

• Eifert, Joseph D.

Committee members dc:contributor.committeemember

• Sumner, Susan S.
• Jahncke, Michael L.

• C. botulinum
• croaker
• spoilage
• vacuum packaging

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Dc Identifier Other

etd-05092007-160646

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/32440