Effects of storage in ozonised slurry ice on the sensory and microbial quality of sardine (Sardina pilchardus)

Abstract

The use of slurry ice, both alone and in combination with ozone, as compared with traditional flake ice was investigated as a new refrigeration system for the storage of sardine (Sardina pilchardus). Microbiological, chemical and sensory analyses were carried out throughout a storage period of 22 days. According to sensory analyses, sardine specimens stored in ozonised slurry ice had a shelf life of 19 days, while counterpart batches stored in slurry ice or flake ice had shelf lives of 15 and 8 days, respectively. Storage in ozonised slurry ice led to significantly lower counts of aerobic mesophiles, psychrotrophic bacteria, anaerobes, coliforms, and both lipolytic and proteolytic microorganisms in sardine muscle, and of surface counts of mesophiles and psychrotrophic bacteria in sardine skin as compared with the slurry ice and the flake ice batches. In all cases, the slurry ice batch also exhibited significantly lower microbial counts, both in muscle and skin, than the flake ice batch. Chemical parameters revealed that the use of slurry ice slowed down the formation of TVB-N and TMA-N to a significant extent in comparison with storage in flake ice, the evolution of TMA-N being the most adequate parameter to detect quality losses. A combination of slurry ice with ozone also allowed a better control of pH and TMA-N formation as compared with slurry ice alone. Proteus vulgaris and Staphylococcus sciuri were identified as the main spoilers of sardine muscle. This work demonstrates that the combined use of slurry ice and ozone for the storage of sardine is can be recommended to improve the quality and extend the shelf life of this fish species.

Ozone: an emerging technology for the seafood industry

“…During the reaction with other molecules, ozone is destroyed. The final products of organic molecule oxidation with ozone are carbon dioxide and the water (Seafish, 1997;King, 2001;Campos et al, 2005;Campos et al, 2006;Vaz-Velho et al, 2006;Chawla, Bell and Marlene, 2007;Zentox, 2007). Unlike other biocides agents such as chlorine, the time necessary to make the disinfection is lower.…”

“…The reactions of oxidation and inactivation always occur very quickly which shows that ozone acts different to chlorine. The chlorine acts selectively oxidizing certain enzymatic systems whereas ozone acts like a "general oxidizing agent" (Brooks and Pierce, 1990;Campos et al, 2005). In addition, with ozone product obtained is with better sensory aspect and presentation, preventing the formation of moulds and putrefaction.…”

“…The catfish study showed highly statistically significant reductions in plate counts when live fish and fillets were washed in ozonated water. It has been claimed that ozone gassing can be used as a powerful surface disinfectant (Tapp and Sopher, 2002;Campos et al, 2005). Ozonated water treatment presents an opportunity to improve the product quality by reducing spoilage bacteria during mechanically peeled shrimp processing operations (Fig.…”

“…On the basis of the results, the combined use of ozone and slurry ice may be recommended for the refrigerated storage of turbot and other flat fish species (Brooks and Pierce, 1990;Campos et al, 2006). Ozone has been traditionally used as a disinfectant for fresh water aquaculture systems: in the treatment of fish and egg's disinfection; sterilization of the water (improve water quality); decomposition of the odorous compounds (geosmin and 2-methyllisoborneol, 2-MIB) in natural waters; and its applications for improving the sensory quality and shelf life of fish have been described recently (Brooks and Pierce, 1990;Morioka et al, 1993;Kötters et al, 1997;Yousef and Dave, 1999;Silva, Chamul and Chen, 2000;King, 2001;Campos et al, 2005;Campos et al, 2006).…”

Combining ozone and slurry ice to maximize shelf-life and quality of bighead croaker (Collichthys niveatus)

“…The combination of a preliminary treatment with antimelanosic agent prior to storage in slurry ice provided a better maintenance of quality, significantly reduced browning reactions, and extended shelf life of lobster as compared with the counterpart method, i.e., no pre-treatment with melanosis inhibitors (Aubourg et al 2007). Likewise, slurry ice enriched with ozone was advisable for megrim, turbot, and sardine storage in previous studies Campos et al 2006Campos et al , 2005. Ozone, an approved disinfectant, has been widely used in a variety of fields because of its release of free oxygen atom along with molecular oxygen.…”