Radiation Sensitization and Postirradiation Proliferation of Listeria monocytogenes on Ready-to-Eat Deli Meat in the Presence of Pectin-Nisin Films†

2009 ◽  
Vol 72 (3) ◽  
pp. 644-649 ◽  
Author(s):  
TONY JIN ◽  
LINSHU LIU ◽  
CHRISTOPHER H. SOMMERS ◽  
GLENN BOYD ◽  
HOWARD ZHANG
Keyword(s):  
Listeria Monocytogenes ◽  
Ionizing Radiation ◽  
Meat Products ◽  
Meat Sample ◽  
Turkey Meat ◽  
Film Treatment ◽  
Microbial Analysis ◽  
Radiation Sensitization ◽  
Meat Samples ◽  
Potential Use

In this study, the ability of pectin-nisin films in combination with ionizing radiation to eliminate Listeria monocytogenes and inhibit its postirradiation proliferation was evaluated. Pectin films containing 0.025% nisin were made by extrusion. The surface of a ready-to-eat turkey meat sample was inoculated with L. monocytogenes at 106 CFU/cm2 and covered with a piece of pectin-nisin film. The samples were vacuum packaged and irradiated at 0, 1, and 2 kGy. The treated samples were stored at 10°C and withdrawn at 0, 1, 2, 4, and 8 weeks for microbial analysis. Reductions in L. monocytogenes viability of 1.42, 1.56, 2.85, 3.78, and 5.36 log CFU/cm2 were achieved for the treatments of 1 kGy, pectin-nisin film, 2 kGy, 1 kGy plus pectin-nisin film, and 2 kGy plus pectin-nisin film, respectively. The greatest reduction (5.5 log CFU/cm2) was observed at 1 week for the 2 kGy plus pectin-nisin film treatment, suggesting that nisin was further released from the film to the surface of meat samples. Pectin-nisin films used in this study did not prevent but did significantly slow (P < 0.05) the proliferation of the L. monocytogenes cells that survived irradiation during 8 weeks of storage at 10°C. These data indicate the potential use of pectin-nisin films alone or in combination with ionizing radiation for preventing listeriosis due to postprocessing contamination of ready-to-eat meat products.

Cross-Contamination between Processing Equipment and Deli Meats by Listeria monocytogenes

2006 ◽  
Vol 69 (1) ◽  
pp. 71-79 ◽  
Author(s):  
CHIA-MIN LIN ◽  
KAZUE TAKEUCHI ◽  
LEI ZHANG ◽  
CYNTHIA B. DOHM ◽  
JOSEPH D. MEYER ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Enrichment Culture ◽  
Meat Products ◽  
Major Product ◽  
Cross Contamination ◽  
Sample Sizes ◽  
Processing Equipment ◽  
Turkey Meat ◽  
Meat Samples ◽  
Sampling Times

Contamination of luncheon meats by Listeria monocytogenes has resulted in outbreaks of listeriosis and major product recalls. Listeriae can survive on processing equipment such as meat slicers which serve as a potential contamination source. This study was conducted to determine (i) the dynamics of cross-contamination of L. monocytogenes from a commercial slicer and associated equipment onto sliced meat products, (ii) the influence of sample size on the efficacy of the BAX-PCR and U.S. Department of Agriculture–Food Safety and Inspection Service enrichment culture assays to detect L. monocytogenes on deli meat, and (iii) the fate of L. monocytogenes on sliced deli meats of different types during refrigerated storage. Three types of deli meats, uncured oven-roasted turkey, salami, and bologna containing sodium diacetate and potassium lactate, were tested. A five-strain mixture of L. monocytogenes was inoculated at ca.103 CFU onto the blade of a commercial slicer. Five consecutive meat slices were packed per package, then vacuum sealed, stored at 4°C, and sampled at 1 and 30 days postslicing. Two sample sizes, 25 g and contents of the entire package of meat, were assayed. Total numbers of L. monocytogenes–positive samples, including the two sample sizes and two sampling times, were 80, 9, and 3 for turkey, salami, and bologna, respectively. A higher percentage of turkey meat samples were L. monocytogenes positive when contents of the entire package were assayed than when the 25-g sample was assayed (12.5 and 7.5%, respectively). Lower inoculum populations of ca. 101 or 102 CFU of L. monocytogenes on the slicer blade were used for an additional evaluation of oven-roasted turkey using two additional sampling times of 60 and 90 days postslicing. L. monocytogenes–positive samples were not detected until 60 days postslicing, and more positive samples were detected at 90 days than at 60 days postslicing. When BAX-PCR and enrichment culture assays were compared, 12, 8, and 2 L. monocytogenes–positive samples were detected by both the enrichment culture and BAX-PCR, BAX-PCR only, and enrichment culture only assays, respectively. The number of L. monocytogenes–positive samples and L. monocytogenes counts increased during storage of turkey meat but decreased for salami and bologna. Significantly more turkey samples were L. monocytogenes positive when the contents of the entire package were sampled than when 25 g was sampled. Our results indicate that L. monocytogenes can be transferred from a contaminated slicer onto meats and can survive or grow better on uncured oven-roasted turkey than on salami or bologna with preservatives. Higher L. monocytogenes cell numbers inoculated on the slicer blade resulted in more L. monocytogenes–positive sliced meat samples. In addition, the BAX-PCR assay was better than the enrichment culture assay at detecting L. monocytogenes on turkey meat (P < 0.05).

Elimination of Listeria monocytogenes from Ready-to-Eat Turkey and Cheese Tortilla Wraps Using Ionizing Radiation†

2005 ◽  
Vol 68 (1) ◽  
pp. 164-167 ◽  
Author(s):  
CHRISTOPHER H. SOMMERS ◽  
GLENN BOYD
Keyword(s):  
Listeria Monocytogenes ◽  
Radiation Dose ◽  
Ionizing Radiation ◽  
Wheat Flour ◽  
Radiation Resistance ◽  
Meat Product ◽  
Processed Cheese ◽  
Turkey Meat ◽  
Luncheon Meat ◽  
The Individual

Listeria monocytogenes is a common postprocess contaminant on ready-to-eat foods including premade ready-to-eat sandwiches. One popular type of sandwich product is the tortilla wrap, which contains sliced luncheon meats and cheeses rolled within a flour tortilla. This study determined the radiation resistance of L. monocytogenes surface inoculated onto two types of commercially available wheat flour tortillas, processed cheese slices, and deli turkey meat. The D10-values for L. monocytogenes (the radiation dose required to inactivate 1 log of the pathogen) were 0.27 kGy when inoculated onto two flour tortilla types, 0.28 and 0.30 kGy when inoculated onto two types of sliced processed cheeses, and 0.58 and 0.65 kGy when inoculated onto two types of sliced deli turkey meat. When two types of tortilla wraps were assembled from the individual components and L. monocytogenes was inoculated into the interfaces between the individual components, the D10-values were 0.27 to 0.37 kGy in the tortilla and cheese interfaces, 0.33 to 0.41 kGy in the cheese and turkey interfaces, and 0.25 to 0.33 kGy in the turkey and tortilla interfaces. The ability of ionizing radiation to reduce pathogen levels on the complex tortilla, cheese, and luncheon meat product was limited by the higher radiation resistance of L. monocytogenes when inoculated onto the ready-to-eat turkey-meat component.

Evaluation of Direct Saponification Method for Determination of Cholesterol in Meats

1986 ◽  
Vol 69 (5) ◽  
pp. 844-846 ◽  
Author(s):  
Mark L Adams ◽  
Darryl M Sullivan ◽  
Randall L Smith ◽  
Earl F Richter
Keyword(s):  
Lipid Extraction ◽  
Meat Products ◽  
Internal Standard ◽  
Meat Sample ◽  
Official Method ◽  
Flame Ionization ◽  
Aoac Method ◽  
Aoac Official ◽  
Meat Samples

Abstract A gas chromatographic (GC) method has been developed for determination of cholesterol in meats. The method involves (a) ethanolic KOH saponification of the sample material, (b) homogeneous-phase toluene extraction of the unsaponifiables, (c) derivatization of cholesterol to its trimethylsilylether, and (d) quantitation by GC-flame ionization detection using 5-α-cholestane as internal standard. This direct saponification method is compared with the current AOAC official method for determination of cholesterol in 20 different meat products. The direct saponification method eliminates the need for initial lipid extraction, thus offering a 30% savings in labor, and requires fewer solvents than the AOAC method. It produced comparable or slightly higher cholesterol results than the AOAC method in all meat samples examined. Precision, determined by assaying a turkey meat sample 16 times over 4 days, was excellent (CV = 1.74%). Average recovery of cholesterol added to meat samples was 99.8%.

Antioxidant Power, Lipid Oxidation, Color, and Viability of Listeria monocytogenes in Beef Bologna Treated with Gamma Radiation and Containing Various Levels of Glucose†

2002 ◽  
Vol 65 (11) ◽  
pp. 1750-1755 ◽  
Author(s):  
CHRISTOPHER H. SOMMERS ◽  
XUETONG FAN
Keyword(s):  
Antioxidant Activity ◽  
Listeria Monocytogenes ◽  
Ionizing Radiation ◽  
Lipid Oxidation ◽  
Thermal Processing ◽  
Meat Products ◽  
Color Analysis ◽  
Antioxidant Power ◽  
Ferric Reducing Antioxidant Power ◽  
Radiation Induced

Ionizing radiation can be used to pasteurize ready-to-eat (RTE) meat products. Thermal processing of RTE meats that contain dextrose results in the production of antioxidants that may interfere with ionizing radiation pasteurization of RTE meat products. Beef bologna was manufactured with dextrose concentrations of 0, 2, 4, 6, and 8%. Antioxidant activity, as measured by the Ferric Reducing Antioxidant Power assay, increased with dextrose concentration but was unaffected by ionizing radiation. Lipid oxidation increased significantly in irradiated bologna (4 kGy) that contained dextrose. Hunter color analysis indicated that the addition of dextrose reduced the ionizing radiation-induced loss of redness (a-value) but promoted the loss of brightness (L-value). The radiation resistance, D10-value, of Listeria monocytogenes that was surface-inoculated onto bologna slices was not affected by dextrose concentration. L. monocytogenes strains isolated from RTE meats after listeriosis outbreaks were utilized. Increased antioxidant activity generated by thermal processing of dextrose in fine emulsion sausages does not present a barrier to radiation pasteurization of RTE meats. However, a high dextrose concentration in combination with gamma irradiation increases lipid oxidation significantly.

Prevalence of Listeria monocytogenes and Salmonella in Ready-to-Eat Food in Catalonia, Spain

2008 ◽  
Vol 71 (4) ◽  
pp. 855-859 ◽  
Author(s):  
L. CABEDO ◽  
L. PICART i BARROT ◽  
A. TEIXIDÓ i CANELLES
Keyword(s):  
Listeria Monocytogenes ◽  
Food Industry ◽  
Pathogenic Bacteria ◽  
Meat Product ◽  
Meat Products ◽  
Smoked Salmon ◽  
Cooked Ham ◽  
Fish Product ◽  
Luncheon Meat ◽  
Meat Samples

Listeria monocytogenes and Salmonella are pathogenic bacteria that can contaminate food products during or after processing. Ready-to-eat (RTE) food does not undergo any treatment to ensure its safety before consumption, and therefore risk of foodborne disease must be considered if these pathogens are present in the food. To evaluate the prevalence of these pathogens in RTE food, 140 RTE fish product samples, 501 RTE meat product samples, 462 RTE dairy samples, and 123 RTE dishes and desserts, providing a total of 1,226 samples, were collected from retail stores and food industry and analyzed for the presence of L. monocytogenes. A total of 1,379 samples consisting of 187 RTE fish products and 569 RTE meat products, 484 RTE dairy products, and 139 RTE dishes and desserts were collected and analyzed for the presence of Salmonella. L. monocytogenes was isolated from 20% of frozen Atlantic bonito small pies, 7.9% of smoked salmon samples, 11.1% of the pork luncheon meat samples, 6.2% of frozen chicken croquettes, 16.9% of cured dried sausage samples, 12.5% of cooked ham samples, and 20% of cooked turkey breast samples. L. monocytogenes was also found to be present in 1.3% of fresh salty cheese samples and 15.1% of frozen cannelloni samples. Salmonella was isolated from 1.2% of smoked salmon samples, 1.5% of frozen chicken croquettes, 2% of cooked ham samples, and 11.1% of cured dried sausage samples. Overall, occurrence of these pathogens in RTE foods was similar to that previously reported in the literature.

scholarly journals THE INFLUENCE OF IONIZING RADIATION ON THE THERMOPHYSICAL PROPERTIES OF MEAT FROM THE BROILER CHICKENS WITH DIFFERENT STRESS RESISTANCE

2019 ◽  
Vol 4 (1) ◽  
pp. 4-8
Author(s):  
Roza T. Timakova ◽  
Sergey L. Tikhonov ◽  
Natal’ya V. Tikhonova ◽  
Sergey V. Shikhalev ◽  
Leonid S. Kudryashov
Keyword(s):  
Ionizing Radiation ◽  
Thermophysical Properties ◽  
Broiler Chickens ◽  
Radiation Treatment ◽  
Meat Product ◽  
Meat Products ◽  
Poultry Meat ◽  
Thermal Processes ◽  
Capacity Coefficient ◽  
Meat Samples

The studies on the influence of radiation treatment of carcasses from the stress-resistant and stress-sensitive broiler chickens on the thermophysical properties of raw meat are presented. An increase in thermal diffusivity of meat from the stress-resistant poultry by 24.7 % and 54.7 % after radiation treatment of carcasses with ionizing radiation doses of 9 kGy and 12 kGy, respectively, was established. In meat from the stress-sensitive poultry, this figure increased by 33.3 % and 35.8 % compared to the untreated carcasses.It is shown that radiation treatment of carcasses by applied doses increased the thermal conductivity coefficient of meat from the stressresistant poultry by 5.3% and 7.0 %; in meat from the stress-sensitive poultry, this figure increased by 2.0 and 6.2 times compared to meat from the carcasses not exposed to radiation. At the same time, the value of the heat capacity coefficient was reduced. The irradiated poultry meat samples accumulate energy of ionizing radiation more intensively, which allows the intensification of the thermal processes occurring at various stages of meat product production. Treatment of meat from the stress-resistant poultry with ionizing radiation can reduce the amount of meat with non-traditional autolysis due to changes in its functionaltechnological properties. The results of the research should be taken into account in technological processes in the production of meat products with non-traditional autolysis.

Radiation (Gamma) Resistance and Postirradiation Growth of Listeria monocytogenes Suspended in Beef Bologna Containing Sodium Diacetate and Potassium Lactate†

2003 ◽  
Vol 66 (11) ◽  
pp. 2051-2056 ◽  
Author(s):  
CHRISTOPHER SOMMERS ◽  
XUETONG FAN ◽  
BRENDAN A. NIEMIRA ◽  
KIMBERLY SOKORAI
Keyword(s):  
Listeria Monocytogenes ◽  
Radiation Dose ◽  
Ionizing Radiation ◽  
Foodborne Pathogen ◽  
Meat Products ◽  
Radiation Doses ◽  
Refrigerated Storage ◽  
Potassium Lactate ◽  
Sodium Diacetate

Listeria monocytogenes, a psychrotrophic foodborne pathogen, is a frequent postprocessing contaminant of ready-to-eat (RTE) meat products, including frankfurters and bologna. Ionizing radiation can eliminate L. monocytogenes from RTE meats. When they are incorporated into fine-emulsion sausages, sodium diacetate (SDA) and potassium lactate (PL) mixtures inhibit the growth of L. monocytogenes. The radiation resistance of L. monocytogenes, and its ability to proliferate during long-term refrigerated storage (9°C), when inoculated into beef bologna that contained 0% SDA–0% PL, 0.07% SDA–1% PL, and 0.15% SDA–2% PL, were determined. The radiation doses required to eliminate 90% of the viable L. monocytogenes cells were 0.56 kGy for bologna containing 0% SDA–0% PL, 0.53 kGy for bologna containing 0.07% SDA–1% PL, and 0.46 kGy for bologna containing 0.15% SDA–2% PL. L. monocytogenes was able to proliferate on bologna containing 0% SDA–0% PL during refrigerated storage, but the onset of proliferation was delayed by the addition of the SDA-PL mixtures. An ionizing radiation dose of 3.0 kGy prevented the proliferation of L. monocytogenes and background microflora in bologna containing 0.07% SDA–1% PL and in bologna containing 0.15% SDA–2% PL over 8 weeks of storage at 9°C. Little effect on lipid oxidation and color of the control bologna, or bologna containing SDA-PL mixtures, was observed upon irradiation at either 1.5 or 3.0 kGy.

scholarly journals Occurrence and molecular characteristics of Listeria monocytogenes isolated from ready-to-eat meats in Hanoi, Vietnam

2020 ◽  
Vol 9 (3) ◽  
Author(s):  
Thuy Phung ◽  
Tung Tran ◽  
Dung Pham ◽  
Anh To ◽  
Hoa Le
Keyword(s):  
Genetic Diversity ◽  
Listeria Monocytogenes ◽  
Spanning Tree ◽  
Minimum Spanning Tree ◽  
Meat Products ◽  
Control Measures ◽  
Molecular Characteristics ◽  
Meat Samples ◽  
And Control ◽  
Sequence Types

Listeria monocytogenes represents one of the most serious threats to food safety. Several studies have shown that Ready-To- Eat (RTE) meats are an important vehicle responsible for listeriosis in human. In Vietnam, little is known about the occurrence and molecular characteristics of L. monocytogenes in meat products, which are essential for developing monitoring plans and control measures. In the present study, we investigated the occurrence of L. monocytogenes in 258 sausage and sliced meat samples collected during the period of 2013-2015 and determined the genetic diversity of the isolates using multi-locus sequence typing (MLST). Overall, L. monocytogenes was present in 19/129 (14.7 %) and 40/129 (31.0 %) sausage and sliced meat samples respectively, with the peak of occurrence being in summer. Furthermore, a minimum spanning tree was constructed based on MLST data of 47 isolates. A total of 15 sequence types were found, with five being novel. Notably, the majority of the isolates (34/47) belonged to the hypervirulent clonal complexes 1, 2, and 3.

Reverse transcription – loop-mediated isothermal amplification assay for the rapid detection of pathogenic Listeria monocytogenes in meat products

2019 ◽  
Vol 65 (12) ◽  
pp. 913-921
Author(s):  
Ling-Zhi Zhan ◽  
Da-Feng Song ◽  
Qing Gu ◽  
Ting-Ting Yan ◽  
Cong-Cong Ma
Keyword(s):  
Listeria Monocytogenes ◽  
Reverse Transcription ◽  
Rapid Detection ◽  
Meat Products ◽  
Isothermal Amplification ◽  
National Standard ◽  
Raw Meat ◽  
Loop Mediated Isothermal Amplification ◽  
Amplification Assay ◽  
Meat Samples

This study reports the use of reverse transcription – loop-mediated isothermal amplification (RT–LAMP) to detect Listeria monocytogenes in meat. The assay was designed to target the iap gene of L. monocytogenes, to which four primers, recognizing six distinct iap sites, were designed. We optimized the RT–LAMP conditions and established the following optimal systems: 60 min, 63 °C, 2.0 mmol/L MgSO4, 1.0 mol/L betaine, 2.0 mmol/L dNTPs, 320 U/mL Bst DNA polymerase, 0.4 μmol/L outer primers, and 0.8 μmol/L inner primers. The RT–LAMP amplification products were identified by a visible white Mg2P2O7 precipitate or electrophoresis on a 2% agarose gel. RT–LAMP has a sensitivity of 7.3 × 101 CFU/mL, which is 2-fold higher than that of LAMP. When commercially available raw meat samples (including beef, pork, mutton, and rabbit) were analyzed simultaneously with RT–LAMP and the Chinese National Standard GB 4789.30-2016, their abilities to detect L. monocytogenes were the same. Samples containing L. monocytogenes killed by 15 psi at 121 °C for 15 min were used to confirm the specificity of RT–LAMP for live microorganisms. Thus, we used RT–LAMP to efficiently detect L. monocytogenes in meat products.

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