Sensorial and microbial effects of gaseous ozone on fresh scad (Trachurus trachurus)

Abstract

The bactericidal activity of gaseous ozone was investigated using a commercial ozone generator. Five species of fish bacteria, Pseudomonas putida, Shewanella putrefaciens, Brochothrix thermosphacta, Enterobacter sp. and Lactobacillus plantarum, were inoculated on agar surfaces and exposed to different ozonation times in a gas chamber. Results showed ozone in relatively low concentrations (< 0.27 x 10(-3) g l-1) was an effective bactericide of vegetative cells of the five fish bacteria. The age of the cell culture was shown to influence the cell response following exposure. Survival rate was not linearly related to ozonation time, but exhibited biphasic death over an extended period. Similar bactericidal effects were observed on fish skin treated with ozone daily in the laboratory, with decreases of 1.0 log cfu cm-2 for the micro-organisms studied. Whole fish treated daily in the laboratory using a commercial ozone generator showed improved scores for sensory analyses compared with the controls. The results were statistically significant. Fish treated on board ships were also analysed for microbiological and sensory changes. Controls were obtained from a similar vessel without the ozone facility in the hold. Similar trends to those recorded in the laboratory for the microbiological and sensory results on ozonated fish were observed.

Effects of ozone treatment on cell growth and ultrastructural changes in bacteria.

“…at 10 6 and 10 7 cfu/ml, a gradual decline in cell survival was demonstrated but ozone did not show effective activity against all bacterial cells even after a prolonged period of treatment (150 min). This finding correlates well with previous reports (da Silva et al, 1998;Lau, 1996, 1998). On the other hand, without ozone treatment, all kinds of control bacterial cultures grew normally after being left at room temperature (28°C) as shown by the increased numbers of bacterial cells (Fig.…”

“…Benjamas Thanomsub, Vipavee Anupunpisit, 1, gram positive and gram negative bacteria (Greene et al, 1993) and caused sensorial and microbial effects on fish bacteria (da Silva et al, 1998). Moreover, damage to cell membranes and cytoplasmic components was proposed to be responsible for inactivation of bacteria and fungi (Hinze et al, 1987;Mudd et al, 1969;Pryor et al, 1991;Scott and Lesher, 1963).…”

“…Generally, most data revealed the antimicrobial effects of ozone against bacteria and virus (da Silva et al, 1998;Herbold et al, 1989;Komanapalli and Lau, 1998;Mackey, 1984). However, the sensitivity of bacteria to ozone varied enormously, depending on many factors.…”

Ozone: an emerging technology for the seafood industry

“…A number of other commercial uses have been found for ozone including disinfection of bottled water, swimming pools, prevention of fouling of cooling towers, and wastewater treatment (Rice, 1997;Gibbs and Kirby, 1998;Tech Brief, 1999;Duguet, 2004;Guzel-Seydim et al, 2004). Since the 1920's scientists have tried to take advantage of long-range disinfection characteristics from ozone, as to slow down the decomposition, as it improve the security of fishing products.…”

“…Any pathogen or contaminant that can be disinfected, altered or removed via an oxidation process will be affected by ozone. It is the strongest of all molecules available for disinfection in water treatment, and is second only to elemental fluorine in oxidizing power (Rice;Farquhar and Bollyky, 1982;Glaze;Kang and Chapin, 1987;Gibbs and Kirby, 1998;King, 2001;Duguet, 2004). Ozone use may have many advantages in the food industry.…”