title: Clostridium botulinum Toxin Production in Relation to Spoilage of Atlantic Salmon (Salmo salar) Packaged in Films of Varying Oxygen Permeabilities and with Different Atmospheres.
abstract: Shelf life of fish packaged under modified atmosphere (MA) is extended, but within the United States, commercial application of MA with impermeable packaging films is restricted due to concerns that botulinum toxin production would precede spoilage when contaminated fish are held at abusive storage temperatures. Use of semipermeable packaging films has been advocated; however, previous studies are inconclusive in determining the oxygen transmission rate (OTR) of a film that is needed to achieve an acceptable margin of safety (i.e., toxin production occurs only after spoilage). This study was conducted to determine the influence of OTR (target OTRs of 3 to 15,000) on the development of spoilage volatiles and toxin in salmon inoculated with type E Clostridium botulinum and subjected to air, vacuum, or 75:25 CO2:N2 MA and storage temperatures of 4, 8, 12, or 16°C. The most dominant headspace volatile peak that was produced during spoilage of samples at 4, 8 or 12°C was a peak, having a Kovats retention index (KI) of 753, and at which external standards of 2- or 3-methyl 1-butanol also eluted. Under anaerobic conditions, both the aerobic microbial populations and the size of the KI 753 spoilage peak were less in inoculated samples compared with uninoculated samples. C. botulinum-inoculated samples that were stored at 12 or 16°C under conditions favorable for anaerobic growth were also characterized by a KI 688 peak. Using a previously developed model that related the percentage of elderly consumers who would prepare a sample having the KI 753 spoilage peak of a specific size, it was determined that for salmon packaged with 3 or 3,000 OTR films under any atmosphere and stored at 12 or 16°C, 2 to 61% of the consumers could potentially prepare toxin-contaminated samples. Hence, when abusive storage conditions are suspected, the fish should not be consumed.
authors.affiliation: Center for Food Safety, Department of Food Science and Technology, University of Georgia, 1109 Experiment Street, Griffin, Georgia 30223-1797, USA. mericks@uga.edu.
authors.forename: Marilyn C
authors.initials: MC
authors.lastname: Erickson
authors.affiliation: National Institute of Microbial Forensics and Food and Agricultural Biosecurity, Oklahoma State University, Stillwater, Oklahoma 74078, USA.
authors.forename: Li M
authors.initials: LM
authors.lastname: Ma
authors.affiliation: Center for Food Safety, Department of Food Science and Technology, University of Georgia, 1109 Experiment Street, Griffin, Georgia 30223-1797, USA.
authors.forename: Michael P
authors.initials: MP
authors.lastname: Doyle
mesh_terms: D000818:Animals; D001905:Botulinum Toxins / Q000096:biosynthesis*; D003014:Clostridium botulinum / Q000254:growth & development / Q000378:metabolism*; D005516:Food Microbiology; D018857:Food Packaging / Q000295:instrumentation*; D006801:Humans; D010100:Oxygen / Q000032:analysis / Q000737:chemistry*; D010539:Permeability; D020317:Salmo salar / Q000382:microbiology*; D013696:Temperature; D014618:Vacuum
chemical_list: D001905:Botulinum Toxins; D010100:Oxygen