Effect of low-dose irradiation and refrigeration on the microflora, sensory characteristics and biogenic amines of Atlantic horse mackerel (trachurus trachurus)

Impact of gamma radiation, potassium sorbate and low temperature on shrimp (Penaeus monodon) preservation

The objective this study was to assess the effect of gamma radiation and 2% potassium sorbate with low temperature (4 °C) for shrimp (Penaeus monodon) preservation. Fresh samples were prepared for treatment with gamma radiation at 1.0 and 1.5 kGy doses and potassium sorbate (2%) soaked for 30 s (PS 30 s) and 60 s (PS 60 s). Organoleptic score (OS), biochemical composition and microbiological analysis were performed to evaluate the shelf-life extension and quality changes during the storage periods. Data showed that combination treatment of gamma irradiation at 1.5 kGy with low temperature was the most effective in extending shelf-life of shrimp. The isolated bacteria associated with shrimp samples were identified through PCR technique. Antibiotic sensitivity test was examined using ten commonly used antibiotics against these pathogenic isolates. Gentamicin and Imipenem showed up to 50% resistance on Gram-positive (Bacillus cereus and Staphylococcus aureus). This study indicates that gamma irradiation treatment with low temperature was most effective way for shelf-life extension of shrimp which might reduce the wastage of this important nutritional source.

Microbiological, chemical and organoleptic evaluation of fresh fish and its products irradiated by gamma rays

The present study evaluated the microbiological, chemical, and organoleptic aspects of irradiated fresh fish and its products to extend their shelf life. Fresh fish and its products were irradiated at three doses (1.5, 3.0, and 4.5 kGy) used for preservation to study the effects of irradiation on their microbiological properties, fatty acid composition, and organoleptic properties. Irradiated fresh bolti fish, smoked herring, and smoked mackerel were evaluated microbiologically, chemically, and organoleptically. Radiation treatment not only reduced the counts of aerobic bacteria, fecal streptococci, molds, and yeasts but also destroyed all the Staphylococcus aureus cells, improving the hygienic quality of the fresh and smoked fish samples. Irradiation increased the peroxide, acid, and thiobarbituric acid values, but they remained within acceptable levels. No new fatty acids or other artifacts due to irradiation were observed. Irradiation of 4.5 kGy greatly reduced the organoleptic quality scores of fresh bolti fish, indicating that the optimum radiation dose for this fish was 3.0 kGy. Smoked herring and mackerel could be irradiated with up to 4.5 kGy without adverse effects on their organoleptic properties.

Innovative Seafood Preservation Technologies: Recent Developments

Fish and fishery products are among the food commodities of high commercial value, high-quality protein content, vitamins, minerals and unsaturated fatty acids, which are beneficial to health. However, seafood products are highly perishable and thus require proper processing to maintain their quality and safety. On the other hand, consumers, nowadays, demand fresh or fresh-like, minimally processed fishery products that do not alter their natural quality attributes. The present article reviews the results of studies published over the last 15 years in the literature on: (i) the main spoilage mechanisms of seafood including contamination with pathogens and (ii) innovative processing technologies applied for the preservation and shelf life extension of seafood products. These primarily include: high hydrostatic pressure, natural preservatives, ozonation, irradiation, pulse light technology and retort pouch processing.

Amino acids and biogenic amines as food quality factors

The importance of amino acids and biogenic amines is widely recognised in various fields, particularly in the fields of food science and nutrition. This mini-review contains a summary of my main research field that centres on aspects of Food Quality and Food Safety, with a particular emphasis on amino acids and biogenic amines. It also gives an overview of the recent developments on the related areas.

Synergistic Effect of Freezing and Irradiation on Bonito Fish ( Sarda sarda Bloch, 1793)

In this study, bonito fish ( Sarda sarda Bloch, 1793) were irradiated at 3 or 5 kGy, packaged, frozen, and stored at -20 ± 2°C for 12 months. During storage, the microbiological, physical, and chemical changes of the fish flesh were then assessed. Increasing the irradiation dose to 5 kGy provided greater inhibition of mesophilic and psychotropic aerobic bacteria (P < 0.05). Because fewer bacteria were detected in irradiated (3 and 5 kGy) as compared with unirradiated control fish suggests that freezing and irradiation yielded better results when combined. Irradiation at 3 and 5 kGy also positively impacted water activity, total volatile basic nitrogen, thiobarbituric acid-reactive substances, trimethylamine, and odor compared with the control group. However, a significant difference was not seen between the 3- and 5-kGy groups in terms of water activity, total volatile basic nitrogen, thiobarbituric acid-reactive substances, trimethylamine, and odor results (P > 0.05). Based on these findings, fish irradiated at 3 and 5 kGy remained within consumable limits during 12 months of frozen storage, while the control group was unacceptable after 9 months.

Effect of gamma radiation on the quality and shelf life of refrigerated rainbow trout (Oncorhynchus mykiss) fillets

The effect of gamma radiation (0, 1, 3, and 5 kGy) on the shelf life of farmed rainbow trout (Oncorhynchus mykiss) fillets that were treated with sodium acetate and vacuum packaged and subsequently stored under refrigeration was studied by measuring microbiological, chemical, and organoleptic changes. Radiation affected populations of bacteria, namely, H2S-producing bacteria and Enterobacteriaceae (P < 0.05). Initial total viable counts of the control samples were ca. 4.41 log CFU/g, whereas the respective counts in samples irradiated at 1, 3, and 5 kGy were 3.08, 1.46, and < or = 1 log CFU/g at day 1 of refrigerated storage. The maximum count of Enterobacteriaceae reached 2.29 and 1.45 log CFU/g at the end of storage for 1 and 3 kGy, respectively, but at a 5-kGy dose no growth of Enterobacteriaceae was observed. Of the biochemical indicators, thiobarbituric acid values for irradiated trout were higher than for nonirradiated fish (P < 0.05). Sensory evaluation (taste) showed a reasonable and good correlation with bacterial populations with storage time. The results revealed that radiation at a high dose (5 kGy) might induce lipid and protein oxidation, although the growth of microorganisms was inhibited. Therefore, radiation at a low dose (3 kGy) could be used to control the microbial and safety biochemical indices of O. mykiss for up to 4 weeks at refrigerator temperature without adverse effects on quality and acceptability.

Impact of irradiation on fish and seafood shelf life: a comprehensive review of applications and irradiation detection

Irradiation is one of the most important and effective methods towards food preservation despite the consumer lack of trust and aversion towards this method. Irradiation effectiveness greatly depends on the dose provided to food. This review aims at summarizing all available information regarding the impact of irradiation dose on the shelf life and microflora and sensory and physical properties of fish, shellfish, molluscs, and crustaceans. The synergistic effect of irradiation in conjunction with other techniques such as salting, smoking, freezing, and vacuum packaging was also reported. Another issue covered within the frame of this review is the detection (comparison of methods in terms of their effectiveness and validity) of irradiated fish and seafood. The information related to fish and seafood irradiation and its detection is presented by means of 11 comprehensive tables and 9 figures.

Influence of Gamma Irradiation on Microbiological, Biochemical, and Textural Properties of Bonito (Sarda sarda) During Chilled Storage

This study evaluates the influence of various doses of gamma irradiation on some quality aspects of iced bonito (Sarda sarda). Fresh bonito sections were aerobically packed and gamma irradiated with doses of 0, 1.5, 3, 4.5, 6, and 7.5 kGy, samples were then chilled during 21 days. Microbiological analyses showed the presence of mesophilic and psychrophilic germs just before irradiation treatment. These germs were eliminated at doses ≥1.5 kGy. The analyses of total volatile basic nitrogen (TVB-N), trimethylamine (TMA) as well as the texture analysis showed that irradiated samples preserved a good quality during 21 days of chilled storage, whereas the control showed putrefaction. Histamine content was reduced after irradiation treatment, such decrease strongly correlated with the applied dose level. Fatty acid composition survey demonstrated that gamma irradiation associated with aerobic packaging influenced significantly the lipid profile. Irradiation at doses of 6 and 7.5 kGy reduced significantly poly-unsaturated fatty acid fraction. Results demonstrated that irradiation amplified the rate of lipid oxidation as shown by an increased peroxide value especially at higher doses. Gamma irradiation at low doses was effective in extending the bonito's shelf-life through the improvement of its microbiological, biochemical and textural qualities up to 21 days of chilled storage.