Temperature Effect on Inactivation Kinetics of Escherichia coli O157:H7 by Electron Beam in Ground Beef, Chicken Breast Meat, and Trout Fillets

Cells of a strain of Lactobacillus lactis selected for ability to produce hydrogen peroxide were added to Trypticase soy broth (TSB) containing Escherichia coli O157:H7 to determine if L. lactis was antagonistic toward the E. coli during storage at 7°C for 7 days. E. coli was enumerated on violet red bile agar. Three strains of E. coli O157:H7 (43894, 43890, and 35150) were evaluated. Control samples containing no L. lactis did not show significant declines in numbers of E. coli during the 7 days of storage. However, samples inoculated with at least 5.0 × 107 L. lactis per ml exhibited significant declines in numbers of E. coli after only 3 days of storage for all strains. Samples inoculated with fewer L. lactis displayed varying effects on E. coli O157:H7 depending on the strain. E. coli O157:H7 strain 43894 appeared to be the most resistant to the antagonistic action of the L. lactis. Interaction experiments in the presence of catalase indicated that hydrogen peroxide was the main factor responsible for the inhibitory action produced by the lactobacilli. Raw chicken breast meat inoculated with E. coli O157:H7 strain 43894 plus the cells of L. lactis and stored at 5°C exhibited declines in numbers of the pathogen, whereas those inoculated only with the E. coli exhibited no declines during storage at 5°C.

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Thermal Inactivation Kinetics of Salmonella and Listeria in Ground Chicken Breast Meat and Liquid Medium

Journal of Food Science ◽

10.1111/j.1365-2621.2000.tb16076.x ◽

2000 ◽

Vol 65 (4) ◽

pp. 706-710 ◽

Cited By ~ 80

Author(s):

R.Y. Murphy ◽

B.P. Marks ◽

E.R. Johnson ◽

M.G. Johnson

Keyword(s):

Liquid Medium ◽

Thermal Inactivation ◽

Chicken Breast ◽

Inactivation Kinetics ◽

Breast Meat ◽

Kinetics Of ◽

Chicken Breast Meat

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Carvacrol and Cinnamaldehyde Facilitate Thermal Destruction of Escherichia coli O157:H7 in Raw Ground Beef†

Journal of Food Protection ◽

10.4315/0362-028x-71.8.1604 ◽

2008 ◽

Vol 71 (8) ◽

pp. 1604-1611 ◽

Cited By ~ 27

Author(s):

VIJAY K. JUNEJA ◽

MENDEL FRIEDMAN

Keyword(s):

Escherichia Coli ◽

Ground Beef ◽

Inactivation Kinetics ◽

Escherichia Coli O157 ◽

Internal Temperature ◽

Circulating Water ◽

Critical Control Points ◽

Thermal Death ◽

D Values ◽

D Value

The heat resistance of a four-strain mixture of Escherichia coli O157:H7 in raw ground beef in both the absence and presence of the antimicrobials carvacrol and cinnamaldehyde was tested at temperatures ranging from 55 to 62.5°C. Inoculated meat packaged in bags was completely immersed in a circulating water bath, cooked for 1 h to an internal temperature of 55, 58, 60, or 62.5°C, and then held for predetermined lengths of time ranging from 210 min at 55°C to 5 min at 62.5°C. The surviving bacteria were enumerated by spiral plating onto tryptic soy agar overlaid with sorbitol MacConkey agar. Inactivation kinetics of the pathogens deviated from first-order kinetics. D-values (time for the bacteria to decrease by 90%) in the control beef ranged from 63.90 min at 55°C to 1.79 min at 62.5°C. D-values determined by a logistic model ranged from 43.18 min (D1, the D-value of a major population of surviving cells) and 89.84 min (D2, the D-value of a minor subpopulation) at 55°C to 1.77 (D1) and 0.78 min (D2) at 62.5°C. The thermal death times suggested that to achieve a 4-D reduction, contaminated processed ground beef should be heated to an internal temperature of 60°C for at least 30.32 min. Significantly increased sensitivity to heat (P < 0.05) was observed with the addition and/or increasing levels of carvacrol or cinnamaldehyde from 0.5 to 1.0%. The observed thermal death times may facilitate the design of acceptance limits at critical control points for ground beef at lower times and temperatures of heating.

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Microbiological and Other Characteristics of Chicken Breast Meat Following Electron-Beam and Sous-Vide Treatments

Journal of Food Protection ◽

10.4315/0362-028x-55.7.528 ◽

1992 ◽

Vol 55 (7) ◽

pp. 528-533 ◽

Cited By ~ 34

Author(s):

K. SHAMSUZZAMAN ◽

N. CHUAQUI-OFFERMANNS ◽

L. LUCHT ◽

T. MCDOUGALL ◽

J. BORSA

Keyword(s):

Electron Beam ◽

Shelf Life ◽

Storage Period ◽

Lethal Effect ◽

Chicken Breast ◽

Slight Reduction ◽

Breast Meat ◽

Thiamine Content ◽

Sous Vide ◽

Chicken Breast Meat

The combined effects of radiation and sous-vide treatment of chicken breast meat were investigated with respect to survival and growth of Listeria monocytogenes, shelf life, thiamine content, and sensory qualities. Chicken breasts were inoculated with L. monocytogenes 81–861 (105 CFU/g), vacuum-packed, irradiated with electron beam (EB) up to 2.9 kGy, and cooked to an internal temperature of 65.6°C. Sous-vide treatment alone had marginal lethal effect on the L. monocytogenes; the residual inoculum reached 107 CFU/g after 8 weeks at 2°C. However, after the combined treatments of sous-vide and EB at 2.9 kGy, the organism remained undetectable during the 8-week storage period. Parallel studies on uninoculated breast meat revealed that sous-vide samples had a shelf life of less than 6 weeks without EB treatment, whereas samples that were irradiated and then received sous-vide treatment had a shelf life of at least 8 weeks. There was a slight reduction in thiamine levels as a result of the EB treatment, but there was essentially no additional loss of thiamine due to the subsequent sous-vide treatment and storage at 2°C. Electron-beam treatment had very little effect on the odor and flavor of the reheated samples. It was concluded that EB treatment combined with sous-vide treatment can greatly enhance the microbial safety and shelf life of chicken breast meat.

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Viability of Salmonella, Escherichia coli O157:H7, and Listeria monocytogenes in Yellow Fat Spreads as Affected by Storage Temperature

Journal of Food Protection ◽

10.4315/0362-028x-66.4.549 ◽

2003 ◽

Vol 66 (4) ◽

pp. 549-558 ◽

Cited By ~ 10

Author(s):

SARAH L. HOLLIDAY ◽

LARRY R. BEUCHAT

Keyword(s):

Escherichia Coli ◽

Listeria Monocytogenes ◽

Storage Temperature ◽

Salt Content ◽

Inactivation Kinetics ◽

Escherichia Coli O157 ◽

E Coli ◽

Inhibition Of Growth ◽

Time Required ◽

Kinetics Of

A study was conducted to characterize the survival and inactivation kinetics of a five-serotype mixture of Salmonella (6.23 to 6.55 log10 CFU per 3.5-ml or 4-g sample), a five-strain mixture of Escherichia coli O157:H7 (5.36 to 6.14 log10 CFU per 3.5-ml or 4-g sample), and a six-strain mixture of Listeria monocytogenes (5.91 to 6.18 log10 CFU per 3.5-ml or 4-g sample) inoculated into seven yellow fat spreads (one margarine, one butter-margarine blend, and five dairy and nondairy spreads and toppings) after formulation and processing and stored at 4.4, 10, and 21°C for up to 94 days. Neither Salmonella nor E. coli O157:H7 grew in any of the test products. The time required for the elimination of each pathogen depended on the product and the storage temperature. Death was more rapid at 21°C than at 4.4 or 10°C. Depending on the product, the time required for the elimination of viable cells at 21°C ranged from 5 to 7 days to >94 days for Salmonella, from 3 to 5 days to 28 to 42 days for E. coli O157:H7, and from 10 to 14 days to >94 days for L. monocytogenes. Death was most rapid in a water-continuous spray product (pH 3.66, 4.12% salt) and least rapid in a butter-margarine blend (pH 6.66, 1.88% salt). E. coli O157:H7 died more rapidly than did Salmonella or L. monocytogenes regardless of storage temperature. Salmonella survived longer in high-fat (≥61%) products than in products with lower fat contents. The inhibition of growth is attributed to factors such as acidic pH, salt content, the presence of preservatives, emulsion characteristics, and nutrient deprivation. L. monocytogenes did not grow in six of the test products, but its population increased between 42 and 63 days in a butter-margarine blend stored at 10°C and between 3 and 7 days when the blend was stored at 21°C. On the basis of the experimental parameters examined in this study, traditional margarine and spreads not containing butter are not “potentially hazardous foods” in that they do not support the growth of Salmonella, E. coli O157:H7, or L. monocytogenes.

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Effects of Low-Dose, Low-Penetration Electron Beam Irradiation of Chilled Beef Carcass Surface Cuts on Escherichia coli O157:H7 and Meat Quality†

Journal of Food Protection ◽

10.4315/0362-028x-68.4.666 ◽

2005 ◽

Vol 68 (4) ◽

pp. 666-672 ◽

Cited By ~ 33

Author(s):

TERRANCE M. ARTHUR ◽

TOMMY L. WHEELER ◽

STEVEN D. SHACKELFORD ◽

JOSEPH M. BOSILEVAC ◽

XIANGWU NOU ◽

...

Keyword(s):

Escherichia Coli ◽

Electron Beam ◽

Low Dose ◽

Ground Beef ◽

Escherichia Coli O157 ◽

Beam Irradiation ◽

Beam Radiation ◽

Beef Carcasses ◽

Antimicrobial Intervention ◽

Potential Use

Low-dose, low-penetration electron beam (E-beam) irradiation was evaluated for potential use as an antimicrobial intervention on beef carcasses during processing. The objectives of this study were (i) to assess the efficacy of E-beam irradiation to reduce concentrations of Escherichia coli O157:H7 on a large beef surface and (ii) to evaluate the effect of the treatment on the sensory properties of the product. A 1-kGy dose of E-beam radiation reduced E. coli O157:H7 inoculated onto sections of cutaneous trunci at least 4 log CFU/cm2. In assessing organoleptic impact, flank steak was used as the model muscle. Flank steaks with various levels of penetration by radiation (5, 10, 25, 50, and 75%) were evaluated. None of the flank steak sensory attributes were affected (P > 0.05) by any penetration treatment. Ground beef formulations consisting of 100, 50, 25, 10, 5, and 0% surface-irradiated beef were tested. A trained sensory panel did not detect any difference between the control (0%) and either the 5 or 10% treatments. These results suggest that if chilled carcasses were subjected to low-dose E-beam irradiation, aroma and flavor of ground beef would not be impacted. The data presented here indicate that low-dose, low-penetration E-beam irradiation has potential use as an antimicrobial intervention on beef carcasses during processing and minimally impacts the organoleptic qualities of the treated beef products.

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A New Kinetic Model for Thermal Inactivation of Microorganisms: Development and Validation Using Escherichia coli O157:H7 as a Test Organism†

Journal of Food Protection ◽

10.4315/0362-028x-64.12.2078 ◽

2001 ◽

Vol 64 (12) ◽

pp. 2078-2082 ◽

Cited By ~ 15

Author(s):

LIHAN HUANG ◽

VIJAY K. JUNEJA

Keyword(s):

Escherichia Coli ◽

Kinetic Model ◽

Thermal Inactivation ◽

Test Organism ◽

Nonlinear Behavior ◽

Ground Beef ◽

Inactivation Kinetics ◽

Escherichia Coli O157 ◽

First Order ◽

Test Microorganism

A new kinetic model has been proposed to simulate the nonlinear behavior of survivor curves frequently observed in thermal inactivation of microorganisms. This model incorporates a time component into the first-order inactivation kinetics and is capable of describing the linear, convex, and concave survivor curves. The model was validated using Escherichia coli O157:H7 as a test microorganism. Ground beef (93% lean) samples inoculated to 107 to 108 CFU/g of meat were subjected to immersion heating at 55, 57.5, 60, 62.5, and 65°C, respectively, in a water bath. All the survivor curves in this study showed upward concavity. Linear and nonlinear regressions were used to fit the survivor curves to the linear first-order inactivation kinetics and the proposed model. Analyses showed that the new kinetic model provides a much better estimate of the thermal inactivation behavior of E. coli O157:H7 in ground beef.

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