Effects of Whey, Whey-derived Lactic Acid and Sodium Lactate on the Surface Microbial Counts of Rainbow Trout Packed in Vacuum Pouches

• Published in: Food science & technology 1998-01, Vol.31 (4), p.361-365
• Main Authors: Nykänen, Anne, Lapveteläinen, Anja, Kallio, Heikki, Salminen, Seppo
• Format: Article
• Language: English
• Subjects: antimicrobial; antimicrobial properties; Biological and medical sciences; dairy byproducts; Fish and seafood industries; Food industries; food packaging; Fundamental and applied biological sciences. Psychology; lactic acid; microbial contamination; Oncorhynchus mykiss; packing; rainbow trout; shelf life; whey
• ISSN: 0023-6438; 1096-1127
• DOI: 10.1006/fstl.1998.0372

The effects of pasteurized sour cream whey, whey-derived lactic acid, and sodium lactate on the microbial surface flora of vacuum-packed rainbow trout (Oncorhynchus mykiss) were examined. The commercial culture used in sour cream production consisted ofLactococcus lactissubspeciescremoris, L.lactisssp.lactis, L.lactisssp.diacetilactisandLeuconostoc mesenteroidesssp.cremoris. After being dipped into test solutions for 2 min (whey, 20 g/L lactic acid or 20 g/L lactate) the fish were vacuum-packed and stored at 0 °C. The enumeration of the aerobic, anaerobic and psychotrophic bacteria of the skin was performed by a plate count after 1, 4, 7 and 10 days' storage. The study was conducted during both spring and autumn. Dipping of fish into whey or lactic acid solution (20 g/L) decreased the microbial growth slightly, whereas 20 g/L sodium lactate solution did not show any anti-microbial effect. Compared to non treated control fish, mesophilic and psychotrophic counts were significantly lower in lactic acid-treated autumn rainbow trout samples after 7 and 10 days of storage.