Effect of Oxygen Tension on the Spoilage Microflora of Irradiated and Non‐irradiated Haddock (<i>Melanogrammus aeglefinus</i>) Fillets

Licciardello, J. J.; Ronsivalli, L.J.; Slavin, J.W.

doi:10.1111/j.1365-2672.1967.tb00294.x

Cited by 15 publications

(4 citation statements)

References 20 publications

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“…Most achromobacters are unable to form acid from sugars (5,9,27), but a small proportion of achromobacters studied have been found to possess this ability (5,27). Many achromobacters appear to be resistant to gamma irradiation and have been isolated as survivors of irradiated fish (11,28,29,35), chicken (42), and meat products (21; strains 80 to 85). Achromobacters characteristically grow well in media supplemented with sodium chloride (about 10%), but also grow adequately in ordinary laboratory media without additional salt (21).…”

Section: Resultsmentioning

confidence: 99%

Transformation Assay for Identification of Psychrotrophic Achromobacters

Juni

Heym

1980

Appl Environ Microbiol

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The finding that many psychrotrophic, gram-negative, nonmotile, oxidase-positive coccobacilli (achromobacters) are competent for genetic transformation made possible the development of a transformation assay that permits recognition of genetically related strains. It has been demonstrated that 109 independently isolated achromobacters are genetically related since deoxyribonucleic acid samples from all of these organisms were able to transform a single competent auxotrophic strain to prototrophy. Genetically interacting bacteria included strains that lacked one or more of the characteristics typical for most achromobacters. An oxidase-negative mutant of one of these strains reacted positively in the transformation assay, unlike other oxidase-negative bacteria. Achromobacters were derived from fish, poultry, irradiated foods, seawater, and other sources. One strain previously classified as Micrococcus cryophilus has been shown to be related to the achromobacters. Two achromobacters had an optimum growth temperature of 35°C and behaved as typical mesophiles. The moraxellae and Acinetobacter were shown to be unrelated to the achromobacters by using the transformation assay. The ready demonstration of genetic relatedness provides a new basis for taxonomic grouping of the psychrotrophic achromobacters.

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Section: Resultsmentioning

confidence: 99%

Transformation Assay for Identification of Psychrotrophic Achromobacters

Juni

Heym

1980

Appl Environ Microbiol

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“…The relatively high radiation susceptibility of pseudomonads is adequately documented (6, 7, 10, 11). Additionally, the role of pseudomonads as the principal spoilage microorganisms in fresh fish has also been adequately documented (1,6,10). It might then be concluded from Fig.…”

Section: Resultsmentioning

confidence: 87%

“…Shrimp and shrimp homogenate were irradiated simultaneously at 0, 10, 20, 30, 40, 50, 60, 80, 100, 150, 200, and 300 krads. Gelatin streak and pour petri plates were irradiated simultaneously at 0, 10,20,30,40,50,60, and 100 krads.…”

Section: Methodsmentioning

confidence: 99%

Variations in the microbial log reduction curves of irradiated cod fillets, shrimp, and their respective homogenates

Green¹,

Kaylor²

1977

Appl Environ Microbiol

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When cod (Gadus morhua morhua) and headless white shrimp (Penaeus setiferus) were gamma irradiated with a series of low-ionizing radiation doses, a "shoulder(s)" was observed in the graph (log microbial counts versus dose) in the approximate range of 25 to 75 krads. When the microbiological survivors were differentiated into total counts, proteolytic and pseudomonad-type bacteria, it was observed that the pseudomonad-type bacteria were rapidly destroyed by 25 krads and that proteolytic bacteria were destroyed at a faster rate than the rest of the microorganisms. When cod fillets and shrimp were compared with their respective homogenates and irradiated at doses of 0, 10, 20, 30, 40, 50, 60, 80, 100, 150, 200, and 300 krads, the homogenates did not exhibit the characteristic shoulders. A further experiment was designed to test surface versus uniform dispersion of microorganisms on/in gelatin disks subjected to low doses of irradiation. Differences were found that may explain the observed differences between solid food materials such as fish fillets and shrimp and their homogenates.

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“…This extended storage life is a direct result of changes both quantitative and qualitative in the microbial flora of fish. A dose of 100 krad has usually been found to bring about a reduction in bacterial numbers of between 1 and 2 log orders, and pseudomonads, which constitute the major spoilage organisms of untreated fish (20), are generally found to be replaced as the principal component of the spoilage flora of irradiated fish by Achromobacter in aerobically stored fish (11,16) and by lactobacilli in vacuum-packaged fish (11,15).…”

mentioning

confidence: 99%

Pseudomonads and Achromobacters in the Spoilage of Irradiated Haddock of Different Preirradiation Quality

Laycock¹,

Regier²

1970

Applied Microbiology

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The effect of initial quality of fish on postirradiation (100 krad) changes in the bacterial flora of haddock fillets during aerobic storage at 3 C has been investigated, with emphasis on the Pseudomonas and Achromobacter groups. The quality was related to the length of time the eviscerated fish had been stored in ice prior to filleting. Increased numbers of organisms, in particular Pseudomonas putrefaciens, were found initially on fillets cut from older fish. Pseudomonads were reduced by 2 to 3 log orders by irradiation, and achromobacters and gram-positive isolates predominated in the immediate postirradiation flora. Little difference could be detected in either types or relative proportions of organisms occurring during storage of unirradiated fish of different quality. Pseudomonads outgrew achromobacters and dominated the spoilage flora in all cases. After spoilage, however, the growth rate of pseudomonads declined markedly. In irradiated fish, achromobacters predominated throughout storage. In fish of better initial quality, bacterial numbers were 1 to 2 log orders higher at spoilage than in their unirradiated counterparts and in the poorer quality of irradiated samples. The increased number of organisms was accompanied by a radical change in the character of the predominant achromobacters. Pseudomonads were found to increase in numbers during storage of irradiated fish, in particular in poorer quality fish on which they were initially present in higher numbers. Detection of pseudomonads, even when present in high numbers, was found to be limited by the identification techniques normally used.

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Effect of Oxygen Tension on the Spoilage Microflora of Irradiated and Non‐irradiated Haddock (Melanogrammus aeglefinus) Fillets

Cited by 15 publications

References 20 publications

Transformation Assay for Identification of Psychrotrophic Achromobacters

Transformation Assay for Identification of Psychrotrophic Achromobacters

Variations in the microbial log reduction curves of irradiated cod fillets, shrimp, and their respective homogenates

Pseudomonads and Achromobacters in the Spoilage of Irradiated Haddock of Different Preirradiation Quality

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