Inactivation‐Rate Studies on a Radiation‐Resistant Spoilage Microorganism III. Thermal Inactivation Rates in Beef<sup>a,</sup><sup>b</sup>

Duggan, D. E.; Anderson, A. W.; Elliker, P. R.

doi:10.1111/j.1365-2621.1963.tb00170.x

Cited by 10 publications

(4 citation statements)

References 6 publications

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“…It was isolated by Anderson et al (1956) from a meat packing plant in Oregon, and besides its very high resistance to ionizing radiation it is also resistant to ultraviolet irradiation (Duggan et aE., 1959). It is not particularly heat resistant (Duggan, Anderson & Elliker, 1963) and is fortunately not pathogenic. It is a large tetrad-forming coccus with salmon pink colonies, and in general properties resembles M .…”

Section: (D) Micrococcus Radioduransmentioning

confidence: 99%

Radiation Resistance among Bacteria

Thornley

1963

Journal of Applied Bacteriology

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Section: (D) Micrococcus Radioduransmentioning

confidence: 99%

Radiation Resistance among Bacteria

Thornley

1963

Journal of Applied Bacteriology

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“…To the best of our knowledge, M. radiodurans is neither a food spoilage organism, a public health hazard, nor a measure of food sanitation. Moreover, it is heat sensitive (Duo0 = 0.75, z = 10.65); the calculations by Duggan et al (10) indicate that a thermal process of 65.6 C (150 F) for 2 min should reduce the contamination cell level in raw beef by a factor of 10-20. Since meat prepared for radiation sterilization is heated to a center temperature of 70 C (158 F) to inactivate the meat enzymes, M. radiodurans would not be expected to present a radiation problem.…”

Section: Resultsmentioning

confidence: 99%

Comparative Resistance of Nonsporogenic Bacteria to Low-Temperature Gamma Irradiation

Anellis

Berkowitz

Kemper

1973

Applied Microbiology

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A total of 36 microorganisms, comprising 19 species of 11 genera, were screened for radiation resistance with 60Co gamma rays at a radiation temperatore of-80 2 C in phosphate buffer (pH 7.0) under vacuum. Micrococcus radiodurans was the most resistant organism. An initial population of 2.8 x 105 cells per dose of this species survived 2.4 but not 2.7 Mrad. Of the remaining 18 species with initial populations of about 10. cells per dose, Streptococcus faecium survived 0.9 to 1.5 Mrad, depending on the strain tested. S. faecalis QM survived 0.9 but not 1.2 Mrad. S. faecalis 1539 and Alcaligenes faecallis survived 0.6 but not 0.9 Mrad. Three species of Salmonella, one strain each of Escherichia coli, Streptococcus lactis, and Aerobacter aerogenes survived 0.3 but not 0.6 Mrad. The remaining 22 bacteria did not survive 0.3 Mrad, the lowest dose tested. Detailed survival curve determinations for four strains of S. faecium, the most resistant of the test bacteria of public health significance, indicated the following order of resistance at-80 C: a21 > 012 = F. > FEC. Each strain produced two exponential survival curves with different slopes, the breaks occurring at 0.3 to 0.5 Mrad. The D values (doses which reduce the microbial population by 90%) of the more resistant cell fractions were twoto threefold higher than the more sensitive cell fraction. The resistance of strain a21 was determined at different radiation temperature (+5,-30,-80,-140,-196 C). The D value-radiation temperature relationship followed a quadratic equation. Computations of Ea and Q%0 values (activation energy and temperature coefficient, respectively) showed a very small thermodynamic effect on radiation death. An Arrhenius evaluation of the temperature effect on cell kill indicated that there was no simple physicochemical mechanism which might explain the change in D value as a function of temperature.

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“…The with PCA + 0.8% NaCl. The times on the abscissa latter, mixed in beef, had aD6o'c = 0.75 mi (7).…”

Section: Time (Min)mentioning

confidence: 99%

“…The radiation-resistant vegetative bacteria isolated from foods include Micrococcus radiodurans (6,25) and other micrococci (5,14) and Moraxella-Acinetobacter (M-A) (26). However, radiation-resistant viruses (24) and vegetative cells such as Micrococcus ra-15S diodurans (1) are heat sensitive (7,23) and would be eliminated or reduced during the thermal process. Any vegetative cells surviving the heat treatment would probably be injured and sensitive to subsequent freezing or irradiation.…”

mentioning

confidence: 99%

Thermal inactivation and injury of Moraxella-Acinetobacter cells in ground beef

Firstenberg‐Eden¹,

Rowley²,

Shattuck³

1980

Appl Environ Microbiol

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The thermal inactivation and injury (sensitivity to 0.8% NaCI) of a radiationresistant culture of Moraxella-Acinetobacter mixed in minced beef were determined. Survival curves for Moraxella-Acinetobacter cells in beef had an initial shoulder preceding a logarithmic decline when the cells were heated at 65, 70, and 750C, but not at 800C. In all cases, the experimental points not included in the shoulder were linearized by means of a least-squares straight line, and the latter was used to determine D values. Shoulder values of 12.2, 4.1, and 0.6 min at temperatures of 65, 70, and 750C were added to the respective D values of 35.4, 6.6, and 1.4 min to determine the time required to destroy one log cycle. The Z value was 7.3°C. Moraxella-Acinetobacter cells in meat were more rapidly injured than inactivated, on initial exposure to heat. The number of cells injured by this initial exposure increased as the temperature was increased. At 650C the percentage of injured cells increased more rapidly with exposure time than did the inactivated cells. As the temperature was increased, the rates of inactivation and injury became more and more similar. Radiation has been proposed as a means of preserving a variety of highly perishable foods (e.g., pork, chicken, beef) for long periods of time under nonrefrigerated conditions (20). In this high-dose (>1 Mrad) process, the above foods are formulated to contain 0.5 to 0.8% (wt/wt) NaCl and 0.3 to 0.4% (wt/wt) sodium tripolyphosphate to improve the juiciness of the final product (21). The formulated food is placed in cellulose casing, heated to an internal temperature of 73 to 770C to inactivate autolytic enzymes, chilled, vacuum packed in cans, frozen to about-40°C, and subjected to gamma irradiation. The dose used in the irradiation process is that which was determined by inoculated-pack studies to reduce the number of spores of the most radiation-resistant strain of Clostridium botulinum by 12 orders of magnitude, i.e., from 1012 to 100 (120).

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Inactivation‐Rate Studies on a Radiation‐Resistant Spoilage Microorganism III. Thermal Inactivation Rates in Beef^a,^b

Cited by 10 publications

References 6 publications

Radiation Resistance among Bacteria

Radiation Resistance among Bacteria

Comparative Resistance of Nonsporogenic Bacteria to Low-Temperature Gamma Irradiation

Thermal inactivation and injury of Moraxella-Acinetobacter cells in ground beef

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Inactivation‐Rate Studies on a Radiation‐Resistant Spoilage Microorganism III. Thermal Inactivation Rates in Beefa,b

Cited by 10 publications

References 6 publications

Radiation Resistance among Bacteria

Radiation Resistance among Bacteria

Comparative Resistance of Nonsporogenic Bacteria to Low-Temperature Gamma Irradiation

Thermal inactivation and injury of Moraxella-Acinetobacter cells in ground beef

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Product

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Inactivation‐Rate Studies on a Radiation‐Resistant Spoilage Microorganism III. Thermal Inactivation Rates in Beef^a,^b