Enterotoxin production and thermal resistance of Yersinia enterocolitica in milk

Francis, David; Spaulding, P L; Lovett, Joseph

doi:10.1128/aem.40.1.174-176.1980

Cited by 51 publications

(16 citation statements)

References 17 publications

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“…The Y. enterocolitica D6, values (0.07-0.1 1 min) obtained in this study are lower than those obtained in other studies at higher heating temperatures (62-62.8C). It is however difficult to make direct comparisons with other reports as the majority of previous workers have investigated liquid systems, most frequently milk (Hanna et al 1977a;Francis et al 1980;Lovett et al 1982;SSrqvist 1989;Toora el al. 1992).…”

Section: Resultsmentioning

confidence: 99%

THERMAL RESISTANCE OF YERSINIA ENTEROCOLITICA AND LISTERIA MONOCYTOGENES IN MEAT AND POTATO SUBSTRATES

Doherty

McMahon

Sheridan

et al. 1998

Journal of Food Safety

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The heat resistance of a wild type and nalidixic acid resistant strain of Yersinia enterocolitica, and Listeria monocytogenes, was measured in meat (minced beef and minced beef homogenate) and potato substrates over the temperature range 50–60C. Comparisons of heat resistance were determined using D‐values calculated using a linear survival model. The results showed that the wild‐type strain of Y. enterocolitica was more heat resistant than the mutant (p<0.05). Under most conditions, the use of a nonselective/overlay recovery medium resulted in higher D‐values compared to a selective recovery medium (p<0.05). Analysis of the data using a nonlinear survival model (D1 and D2 ‐values) suggested the presence of heat resistant subpopulations and was particularly evident for the mutant strain, and in potatoes compared to minced beef.

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Section: Resultsmentioning

confidence: 99%

THERMAL RESISTANCE OF YERSINIA ENTEROCOLITICA AND LISTERIA MONOCYTOGENES IN MEAT AND POTATO SUBSTRATES

Doherty

McMahon

Sheridan

et al. 1998

Journal of Food Safety

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“…Only a few reports giving detailed information about the heat sensitivity of yersinias (Hanna et al 1977;Francis et al 1980;Lovett et al 1982) and campylobacters (Doyle & Roman 1981;Christopher et al 1982;Blankenship & Craven 1982;Waterman 1982) when suspended in liquids have been found. These investigations were performed in other heating menstrua than physiological saline.…”

Section: Glass Cups 58 26mentioning

confidence: 99%

Heat resistance of Campylobacter and Yersinia strains by three methods

Sörqvist

1989

Journal of Applied Bacteriology

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Two methods of determining the heat resistance of bacteria, a glass cup and a test tube method, were compared with a method using capillary tubes. Three strains of Yersinia enterocolitica, one of Campylobacter jejuni and two of C. coli were tested in physiological saline. The differences between the results obtained by the glass cup method and the reference method were not statistically significant for five strains and were small also for the other, a Yersinia strain. D values obtained by the glass cup method at 58, 60 and 62 degrees C were 1.4-1.8, 0.40-0.51 and 0.15-0.19 min (zeta values 4.00-4.52 degrees C) for the Yersinia strains, and 0.42, 0.13 and 0.07 min (zeta value 5.07 degrees C) for one C. coli strain. For the other Campylobacter strains, D values of 0.71-0.78, 0.24-0.28 and 0.12-0.14 min (zeta values 4.94 and 5.60 degrees C) were recorded at 56, 58 and 60 degrees C. D values obtained at 60 degrees C by the test tube method were 2.7-5.0 min and were considered to be unrealistic.

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“…oxytoca have also been found by Gaya et al (1987) in ewes' milk in proportions similar to our finding. The presence of Y. enterocolitica is of concern as it can produce heat-resistant enterotoxins in milk stored at room temperature (Francis et al 1980;Olsvik and Kapperud 1982). This micro-organism is frequently isolated from raw milk (Larkin et al 1991).…”

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confidence: 99%

Study of Enterobacteriaceae throughout the manufacturing and ripening of hard goats' cheese

Tornadijo

Fresno

Carballo

et al. 1993

Journal of Applied Bacteriology

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The evolution of the counts and the species of Enterobacteriaceae as well as some physico-chemical parameters (pH, aw and NaCl and moisture contents) during manufacturing and ripening of a hard Spanish goats' cheese of the Armada-Sobado variety were studied. Enterobacteriaceae (mean log counts 4.45 g-1 in milk) increased 0.71-2.18 log units in curd and afterwards decreased until they disappeared after 2-4 weeks of ripening. This premature disappearance seems to be due to the decrease in aw values and in moisture contents. However, the low pH values, reached from the beginning of the ripening process, could also contribute to this phenomenon. The most abundant species in milk was Serratia liquefaciens (57.5% of isolates), followed by Morganella morganii (27.5%), Hafnia alvei (5%), Klebsiella oxytoca (5%) and Yersinia enterocolitica (5%). Yersinia enterocolitica was not subsequently isolated from either curd or in cheese. Hafnia alvei numbers increased in curd and in 1-week-old cheese where this micro-organism was the most abundant (47.5% and 75% of the isolates respectively). Escherichia coli, which was not isolated from milk, curd or 1-week-old cheese, was the predominant organism in 2-week-old cheese (57.8% of isolates). This confirms the finding of other authors who have shown that it is one of the most resistant species in ripening cheeses.

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Enterotoxin production and thermal resistance of Yersinia enterocolitica in milk

Abstract: Three of 36 raw milk isolates of Yersinia enterocolitica produced enterotoxin in milk at 25 degrees C, but not at 4 degrees C. No strain tested could survive pasteurization.

Cited by 51 publications

References 17 publications

THERMAL RESISTANCE OF YERSINIA ENTEROCOLITICA AND LISTERIA MONOCYTOGENES IN MEAT AND POTATO SUBSTRATES

THERMAL RESISTANCE OF YERSINIA ENTEROCOLITICA AND LISTERIA MONOCYTOGENES IN MEAT AND POTATO SUBSTRATES

Heat resistance of Campylobacter and Yersinia strains by three methods

Study of Enterobacteriaceae throughout the manufacturing and ripening of hard goats' cheese

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