Impact of -2 degrees C superchilling before refrigerated storage (4 and 8 degrees C) on the microbiological and sensory qualities of cold-smoked salmon.
Detection and enumeration of Listeria monocytogenes and total spoilage bacteria in 40 batches of cold-smoked salmon (one batch = 42 products from the same day of manufacture) straight from the factory were carried out. If L. monocytogenes was detected in at least one of the nine samples analyzed on receipt at the laboratory, 9 products of the same batch were stored for 10 days at 4 degrees C, which was followed by 18 days at 8 degrees C (control), 12 products were superchilled for 14 days at -2 degrees C, and 12 other products were superchilled for 28 days at -2 degrees C and then stored under the same conditions as the control was stored. L. monocytogenes was detected in 7% of the 40 batches analyzed immediately after receipt at the laboratory. L. monocytogenes prevalence was similar (approximately 25%) throughout the storage at 4 and 8 degrees C, both in control and super-chilled products at -2 degrees C for 14 days. After superchilling for 28 days at -2 degrees C, L. monocytogenes was found in 9% of products, and in 39% at the end of the storage above 0 degree C. Moreover, the L. monocytogenes count was higher after 3 and 4 weeks of storage at 4 and 8 degrees C in products superchilled 28 days at -2 degrees C than in control products or in products superchilled for 14 days. Serotype 1/2a-3a and nine genetic groups were identified and found throughout the storage scenario. At the end of shelf life, sensory characteristics of products superchilled for 28 days at -2 degrees C were slightly modified. A decrease in firmness associated with increased tearing of salmon slices was observed as well as a slight amine odor.
Midelet-Bourdin
Graziella
G
Agence Française de Sécurité Sanitaire des Aliments, Laboratoire d'Etudes et de Recherches sur les produits de la pêche, Boulogne sur Mer, France. g.bourdin@boulogne.afssa.fr
Beaufort
Annie
A
Leroi
Françoise
F
Cardinal
Mireille
M
Rudelle
Sylvie
S
Leleu
Guylaine
G
Copin
Stephanie
S
Malle
Pierre
P
D000818:Animals; D003080:Cold Temperature; D015169:Colony Count, Microbial; D003257:Consumer Product Safety; D005506:Food Contamination / Q000032:analysis; D005511:Food Handling / Q000379:methods*; D005516:Food Microbiology; D005519:Food Preservation / Q000379:methods*; D008089:Listeria monocytogenes / Q000254:growth & development*; D012034:Refrigeration; D012474:Salmon / Q000382:microbiology*; D017747:Seafood / Q000382:microbiology* / Q000592:standards*; D013649:Taste; D013997:Time Factors