Effect of freezing of water samples on viable counts of environmental mycobacteria

Livanainen, E.; Martikainen, Pertti J.; Katila, Marja–Leena

doi:10.1111/j.1472-765x.1995.tb01055.x

Cited by 12 publications

(10 citation statements)

References 12 publications

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“…Viable mycobacteria were predominantly isolated from frozen fish samples. As has been previously demonstrated, freezing did not devitalize mycobacteria during storage of samples including frozen fish (Livanainen et al, 1995;Mediel et al, 2000).…”

supporting

confidence: 51%

Nontuberculous Mycobacteria in Freshwater Fish and Fish Products Intended for Human Consumption

Lorencova

Klanicova

Makovcová

et al. 2013

Foodborne Pathogens and Disease

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Nontuberculous mycobacteria (NTM) are potentially pathogenic agents commonly found in natural ecosystems, while food is considered to be another source of NTM for humans. We investigated a total of 92 tissue samples of freshwater fish and fish products: fish directly obtained from ponds (n=25), retail fresh (n=23) and frozen fish (n=23) and smoked fish products (n=21). Culture examination for the presence of mycobacteria was positive in 11 (11.9%) from all the examined samples. The 15 obtained isolates were identified as Mycobacterium fortuitum (n=5), M. immunogenum (n=2), M. phocaicum/ mucogenicum (n=1), M. neoaurum (n=2), M. peregrinum (n=2), M. porcinum (n=1) and M. senegalense/houstonense/conceptionense (n=2). NTM DNA was found in one (4.0%) sample of fresh fish from ponds and in 60.9% and 91.3% of retail fresh and frozen fish, respectively. None of the smoked fish products contained NTM DNA. The results of our study suggest that freshwater fish and fish products, especially retail frozen fish, might be a reservoir of NTM for humans, and proper handling and treatment before consumption of such products is recommended.

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confidence: 51%

Nontuberculous Mycobacteria in Freshwater Fish and Fish Products Intended for Human Consumption

Lorencova

Klanicova

Makovcová

et al. 2013

Foodborne Pathogens and Disease

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“…1998). The long‐term storage of brook water concentrates at −75 °C has increased, rather than decreased, the culturable counts of mycobacteria (Iivanainen et al . 1995).…”

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confidence: 99%

Environmental factors affecting the occurrence of mycobacteria in brook sediments

Iivanainen

Martikainen

Väauml

et al. 1999

Journal of Applied Microbiology

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E. IIVANAINEN, P.J. MARTIKAINEN, P. VÄ Ä NÄ NE N A N D M .-L . K AT I LA . 1999. The occurrence of mycobacteria was studied in aerobic brook sediments from 39 drainage areas in Finland. The culturable counts of mycobacteria were related to climatic conditions, characteristics of the drainage area, chemical characteristics of the sediment and water, culturable counts of other heterotrophic bacteria, and microbial respiration rate in the sediment. The counts of mycobacteria varied from 1·1 × 10 2 to 1·5 × 10 4 cfu g −1 dry weight of sediment. They correlated positively with the proportion of the drainage area consisting of peatland, total content of C, content of Pb, microbial respiration rate in the sediment, and chemical oxygen demand of the water. The correlations of the mycobacterial counts with pH of sediment and alkalinity of water were negative. The results of the present sediment study and of the forest soil study published earlier strongly suggest that an increase in acidity increases the counts of mycobacteria and decreases the counts and activity of other heterotrophic bacteria. Mycobacterial counts were more than 100 times higher (per dry weight) in forest soils with pH 3·5-4·3 than in sediments with pH 4·5-6·3.

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“…Strains are known that have remained viable in nutrient broth at Ϫ70°C for years (11,13). This may be due to the specific properties of their cell walls, such as high lipid content and therefore hydrophobicity, which renders them resistant to changes in environmental conditions (14).…”

mentioning

confidence: 99%

Isolation of Mycobacteria from Frozen Fish Destined for Human Consumption

Mediel

Rodriguez

Codina

et al. 2000

Appl Environ Microbiol

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Mycobacteria were isolated from defrost water and tissue of sole (Solea solea), hake (Merluccius merluccius), cod (Gadus morhua), ling (Genypterus blacodes), and monkfish (Lophius piscatorius) on Löwenstein-Jensen medium after incubation at different temperatures. Samples of frozen fish were obtained under sterile conditions inside a refrigeration chamber (؊18 to ؊22°C) in a wholesale market from which these products are distributed to shops for retail sale and human consumption.Nontuberculous mycobacteria (NTM) are transmitted to humans from the environment, including through ingestion of food. They have been isolated from beef, pork, lamb (19), milk and other dairy products (8, 16, 18, 21, 22, 23), water (1, 7, 10, 20), vegetables (broccoli, spinach, and lettuce) (24), fruit (cherries, pomegranates, and apples) (24), preserves and brine (19), herbs (basil and parsley) (24), oysters (18), and fish such as Pacific salmon (2) and Channa striatus (4). The objectives of all of these studies were to show the presence of mycobacteria in food samples and analyze these possible sources of human infection or colonization.Mycobacteria can survive under environmental conditions that are intolerable for most other bacterial genera, including temperatures below 0°C. Strains are known that have remained viable in nutrient broth at Ϫ70°C for years (11,13). This may be due to the specific properties of their cell walls, such as high lipid content and therefore hydrophobicity, which renders them resistant to changes in environmental conditions (14).Due to the association between mycobacteria and a variety of different aqueous environments (3, 5, 9, 15), it seems reasonable to believe that these organisms may occur in frozen foods, including fish, which are widely consumed by humans. When fish is frozen in order to preserve quality, microorganisms are inevitably included.Our objective was to find out whether frozen fish contains NTM from which humans could be colonized.Samples of frozen fish were obtained under sterile conditions inside a refrigeration chamber (temperature between Ϫ18 and Ϫ22°C) in a wholesale market from which these products are distributed to shops for retail sale and human consumption. The fish and their origins were as follows: Solea solea from Denmark, Merluccius merluccius from Spain, Gadus morhua from Iceland, Genypterus blacodes from Argentina, and Lophius piscatorius from Ireland. Ten samples of each of the five species of fish, a total of 50 samples, were analyzed. When the samples were obtained, the fish product was individually vacuum packed in plastic bags in the case of G. morhua, G. blacodes, and L. piscatorius whereas the samples of S. solea were also individually wrapped in plastic but not vacuum packed. The pieces of M. merluccius were packed in a single plastic food grade bag.All of the fish had been gutted and frozen, with the head and caudal fin removed, and cut longitudinally into boneless fillets in the case of S. solea, boneless steaks in the case of G. morhua, and transverse slices in t...

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Effect of freezing of water samples on viable counts of environmental mycobacteria

Cited by 12 publications

References 12 publications

Nontuberculous Mycobacteria in Freshwater Fish and Fish Products Intended for Human Consumption

Nontuberculous Mycobacteria in Freshwater Fish and Fish Products Intended for Human Consumption

Environmental factors affecting the occurrence of mycobacteria in brook sediments

Isolation of Mycobacteria from Frozen Fish Destined for Human Consumption

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