Thermal Tolerance Studies on the Heterofermentative Lactobacilli That Cause Greening of Cured Meat Products1

Niven, C. F.; Buettner, L. G.; Evans, James B.

doi:10.1128/aem.2.1.26-29.1954

Cited by 27 publications

(5 citation statements)

References 7 publications

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“…Even after the initial separation of S. senftenberg 775W into rough and smooth cultures as described under Materials and Methods, a high degree of instability of each remained, with interme-diate forms appearing regularly. Limited tests of some of these variants indicated that their resistance to thermal killing was closer to that of the smooth strain than the rough, although there was considerable variation among those examined, with the results resembling those reported among various lactobacilli by Niven et al (11). Two derivatives of strain 775W-R which formed apparently smooth colonies on an agar surface were submitted for serotyping.…”

Section: Methodsmentioning

confidence: 74%

Thermal Resistance of Salmonellae and Staphylococci in Foods

Thomas

White

Longrée

1966

Applied Microbiology

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The heat-resistant Salmonella senftenberg 775W and two strains of Staphylococcus aureus were tested at temperatures up to 68.3 C (71.1 C for S. senftenberg) in four different media. From the survival data, decimal reduction times (D values) were calculated for each set of conditions, and decimal reduction time curves were constructed for each bacterial strain in each medium. Slopes of decimal reduction time curves (ZD) ranged from 4.52 to 6.38 C with a single exception. There was no statistical heterogeneity among the remaining values. Results were in close agreement with published results of similar studies conducted at somewhat lower temperatures and support the practice of using a slope value (ZD) of 5.56 C for establishing time-temperature relationships for food processing. It is recommended that such a decimal reduction time curve not be extrapolated to temperatures more than 5.56 C higher than those actually tested. Modern technology has made available many new food products, frozen, canned, or dried, both cooked and uncooked. The wide distribution of many of these products, with their increasing use for quantity service in cafeterias and large

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Section: Methodsmentioning

confidence: 74%

Thermal Resistance of Salmonellae and Staphylococci in Foods

Thomas

White

Longrée

1966

Applied Microbiology

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“…We applied a selection procedure consisting of alternating cycles of pressure exposure and outgrowth of surviving E. coli populations. Similar procedures using repeated exposure of surviving populations to irradiation or heat have been used previously to develop radioresistance or thermoresistance, respectively, in populations of E. coli or Salmonella or Lactobacillus species (5,20,24,33).…”

mentioning

confidence: 99%

Escherichia coli mutants resistant to inactivation by high hydrostatic pressure

Hauben

Bartlett

Soontjens

et al. 1997

Appl Environ Microbiol

208

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Alternating cycles of exposure to high pressure and outgrowth of surviving populations were used to select for highly pressure-resistant mutants of Escherichia coli MG1655. Three barotolerant mutants (LMM1010, LMM1020, and LMM1030) were isolated independently by using outgrowth temperatures of 30, 37, and 42؇C, respectively. Survival of these mutants after pressure treatment for 15 min at ambient temperature was 40 to 85% at 220 MPa and 0.5 to 1.5% at 800 MPa, while survival of the parent strain, MG1655, decreased from 15% at 220 MPa to 2 ؋ 10 ؊8 % at 700 MPa. Heat resistance of mutants LMM1020 and LMM1030 was also altered, as evident by higher D values at 58 and 60؇C and reduced z values compared to those for the parent strain. D and z values for mutant LMM1010 were not significantly different from those for the parent strain. Pressure sensitivity of the mutants increased from 10 to 50؇C, as opposed to the parent strain, which showed a minimum around 40؇C. The ability of the mutants to grow at moderately elevated pressure (50 MPa) was reduced at temperatures above 37؇C, indicating that resistance to pressure inactivation is unrelated to barotolerant growth. The development of high levels of barotolerance as demonstrated in this work should cause concern about the safety of high-pressure food processing.

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“…Members of this species have been found to possess some rather unusual nutritional requirements (Evans and Niven, 1951;Deibel et al, 1955), and to show a wide range of heat tolerance (Niven et al, 1954).…”

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confidence: 99%