Nr. Reddy et al., SHELF-LIFE AND TOXIN DEVELOPMENT BY CLOSTRIDIUM-BOTULINUM DURING STORAGE OF MODIFIED-ATMOSPHERE-PACKAGED FRESH AQUACULTURED SALMON FILLETS, Journal of food protection, 60(9), 1997, pp. 1055-1063
Shelf Life (onset of sensory spoilage) and the potential for toxin pro
duction by Clostridium botulinum type E in retail-type packages of fre
sh aquacultured salmon fillets packaged in high-barrier film bags unde
r selected atmospheres (100% air, a modified atmosphere containing 75%
CO2:25% N-2, and vacuum) and stored under refrigeration (4 degrees C)
and temperature-abuse conditions (8 and 16 degrees C) were investigat
ed. Chemical spoilage indicators (trimethylamine and surface pH) and m
icrobial populations were compared with sensory spoilage characteristi
cs. Storage temperature influenced the time to onset of both sensory s
poilage and toxin development in salmon fillets packaged in all atmosp
heres. The shelf Life of fillets packaged in all atmospheres decreased
with increase of storage temperature from 4 to 16 degrees C. Trimethy
lamine content associated with the onset of spoilage for 100% air-pack
aged fillets increased as storage temperature increased. However, for
modified-atmosphere-packaged fillets, the trimethylamine content assoc
iated with the onset of spoilage increased as storage temperature decr
eased from 8 to 4 degrees C. Surface pH was not a good spoilage indica
tor for modified-atmosphere-packaged fillets. Toxin development preced
ed sensory spoilage at 16 degrees C storage for fillets packaged in mo
dified atmospheres, Toxin development coincided with sensory spoilage
or was slightly delayed for the fillets packaged in all the atmosphere
s at 8 degrees C storage. At 4 degrees C none of the fillets packaged
in either of the atmospheres developed toxin, even 20 days after spoil
age as determined by sensory characteristics.