A Comparison Study of Quality Attributes of Ground Beef and Veal Patties and Thermal Inactivation of Escherichia coli O157:H7 after Double Pan-Broiling Under Dynamic Conditions (original) (raw)
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Journal of Food Science, 2011
This study evaluated inactivation of Escherichia coli O157:H7 in moisture-enhanced restructured nonintact beef cooked to 65 • C using different cooking appliances set at different temperatures. Batches (2 kg) of coarse-ground beef (approximately 5% fat) were mixed with an 8-strain composite (100 mL) of rifampicin-resistant E. coli O157:H7 (6.4 ± 0.1 log CFU/g) and a solution (100 mL) of sodium chloride plus sodium tripolyphosphate to yield concentrations (wt/wt) of 0.5% and 0.25%, respectively, in the final product. Beef portions of 2.54 cm thickness (15 cm dia) were prepared and were vacuum-packaged and frozen (−20 • C, 42 h). Partially thawed (−2.5 ± 1.0 • C) portions were pan-broiled (Presto R electric skillet and Sanyo R grill) or roasted (Oster R toaster oven and Magic Chef R kitchen oven) to 65 • C. The appliances were set at, and preheated before cooking to 149 or 204 • C (electric skillet), 149 or 218 • C (grill), 149 or 232 • C (toaster oven), and 149, 204, or 260 • C (kitchen oven). Temperatures of appliances and beef samples were monitored with thermocouples, and meat samples were analyzed for surviving microbial populations. In general, the higher the appliance temperature setting, the shorter the time needed to reach 65 • C, and the higher the edge and surface temperatures of the meat samples. Temperatures of 204 to 260 • C, regardless of appliance, resulted in greater (P < 0.05) pathogen reductions (3.3 to 5.5 log CFU/g) than those obtained at 149 • C (1.5 to 2.4 log CFU/g). The highest (P < 0.05) reduction (5.5 log CFU/g) was obtained in samples cooked in the kitchen oven set at 260 • C. The results should be useful to the food service industry for selection of effective nonintact beef cooking protocols, and for use in risk assessments for nonintact meat products.
Meat Science, 2013
This study evaluated chemical tenderizers and cooking methods to inactivate Escherichia coli O157:H7 in ground beef patties (model system for non-intact beef). Ground beef was inoculated with E. coli O157:H7 and mixed with (i) nothing (control), (ii) calcium chloride (CC) and flavoring agents (FA), (iii) CC, FA, and acetic acid (AA), (iv) sodium chloride (SC), sodium tripolyphosphate (ST), and potassium lactate (PL), and (v) the combination of SC, ST, PL, and AA. Patties were stored in aerobic or vacuum bags at − 20, 4, and 12°C. Samples were grilled, broiled, or pan-fried to 60 or 65°C. Total bacterial and E. coli O157:H7 populations remained unchanged during storage. Broiling was more effective in reducing E. coli O157:H7 than grilling and pan-frying, and acidified tenderizers reduced E. coli O157:H7 more than non-acidified tenderizers in broiling. Higher reductions were observed at 65°C than 60°C in broiled and grilled samples. These results indicate that acidified tenderizers and broiling may be useful in non-intact beef safety.
Journal of food protection, 2010
This study compared thermal inactivation of Escherichia coli O157:H7 in nonintact beefsteaks of different thicknesses by different cooking methods and appliances. Coarsely ground beef was inoculated with rifampin-resistant E. coli O157:H7 (eight-strain composite, 6 to 7 log CFU/g) and then mixed with sodium chloride (0.45%) plus sodium tripolyphosphate (0.23%); the total water added was 10%. The meat was stuffed into bags (10-cm diameter), semifrozen (-20 degrees C, 6 h), and cut into 1.5-, 2.5-, and 4.0-cm-thick steaks. Samples were then individually vacuum packaged, frozen (-20 degrees C, 42 h), and tempered (4 degrees C, 2.5 h) before cooking. Partially thawed (-2 +/- 1 degrees C) steaks were pan broiled (Presto electric skillet and Sanyo grill), double pan broiled (George Foreman grill), or roasted (Oster toaster oven and Magic Chef standard kitchen oven) to a geometric center temperature of 65 degrees C. Extent of pathogen inactivation decreased in order of roasting (2.0 to 4.2...
Journal of Food Science, 2009
This study evaluated the effects of meat binding or restructuring formulations, including salt/phosphate, algin/calcium, Activa TM RM, and Fibrimex R , with or without 0.27% (wt/wt) lactic acid, on thermal inactivation of internalized Escherichia coli O157:H7 in ground beef, serving as a model system for restructured products. Ground beef batches (700 g; approximately 5% fat) were mechanically mixed with a 5-strain composite of E. coli O157:H7 (7 log CFU/g) and then with the restructuring formulations. Product portions (30 g) were extruded into plastic test tubes (2.5 × 10 cm) and stored at 4 • C (18 h), before heating to 60 or 65 • C in a circulating water bath to simulate rare or medium-rare doneness of beef, respectively. Cooking to 60 or 65 • C reduced (P < 0.05) bacterial counts of control samples by 1.8 and 3.2 log CFU/g, respectively. Thermal destruction at 60 • C was not different (P > 0.05) among all treatments and the control. At 65 • C, greater (P < 0.05) thermal inactivation of E. coli O157:H7, as compared to the control, was obtained in samples treated with lactic acid alone (reductions of 4.9 log CFU/g), whereas for all other treatments, microbial destruction (reductions of 2.2 to 4.5 log CFU/g) was comparable (P > 0.05) to that of the control. Cooking weight losses were lower (P < 0.05) in salt/phosphate samples (<1%) compared to other formulations and the control (7.4% to 15.9%). Findings indicated that, under the conditions examined, restructuring of beef with salt/phosphate, algin/calcium, Activa TM RM, or Fibrimex R did not affect inactivation of internalized E. coli O157:H7 in undercooked (60 or 65 • C) samples, whereas inclusion of lactic acid (0.27%) in nonintact beef products enhanced pathogen destruction at 65 • C.
International Journal of Food Microbiology, 1997
We investigated the heat resistance of a four-strain mixture of Escherichia coli O157:H7 in raw ground beef in both the absence and presence of white and green tea powders and an apple skin extract. Inoculated meat was cooked using the sousvide technique, i.e., the meat was packaged in sterile bags and completely immersed in a circulating water bath at low temperature for a period of time. The bags were cooked for 1 h to an internal temperature of 55, 58, 60, or 62.5ЊC, and then held from 240 min at 55ЊC to 10 min at 62.5ЊC. 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, in minutes, required for the bacteria to decrease by 90%) in the control beef ranged from 67.79 min at 55ЊC to 2.01 min at 62.5ЊC. D-values determined by a logistic model ranged from 36.22 (D 1 , the D-value of a major population of surviving cells) and 112.79 (D 2 , the D-value of a minor subpopulation) at 55ЊC to 1.39 (D 1) and 3.00 (D 2) at 62.5ЊC. A significant increase (P Ͻ 0.05) in the sensitivity of the bacteria to heat was observed with the addition of 3% added antimicrobials. D-value reductions of 62 to 74% were observed with apple powder and 18 to 58% with tea powders. Thermal death times from this study will assist the retail food industry to design cooking regimes that ensure the safety of beef contaminated with E. coli O157:H7.
Heat-Resistance of Escherichia Coli O157:H7 in Meat and Poultry as Affected by Product Composition
Journal of Food Science, 1995
The effects of fat level and low fat formulation on survival of Escherichiu coli 0157:H7 isolate 204P heated in ground beef [7%, 10% and 20% fat], pork sausage [7%, lo%, and 30% fat], chicken (3% and 11% fat), and turkey (3% and 11% fat) were determined by D-and z-values. D-values for E. coli 0157:H7 in lowest fat products were lower than in traditional beef and pork products (P < 0.05). Overall, higher fat levels in all products resulted in higher D-values. D,, values (min) ranged from 0.4550.47 in beef, 0.37-0.55 in pork sausage, 0.38-0.55 in chicken and 0.5550.58 in turkey. D,, and D,, values were respectively longer. Zvalues ranged from 4.44.8"C. Product composition affected lethality of heat to E. coli 0157:H7.
Kansas Agricultural Experiment Station Research Reports, 2005
USDA/FSIS guidelines require sausage manufacturers to validate their processes to assure that they can achieve a five-log (99.999%) reduction of E. coli O157:H7. Some small meat processors use encapsulated acids instead of lactic acid starter cultures to produce directly acidified sausages. The objectives of this study were to determine 1) the effects of typical thermal processing temperatures and times on reducing E. coli O157:H7 in directly acidified all-beef and venisoncontaining beef snack sticks, 2) the effect of fat content (10 and 25%) on lethality, and 3) the effect of acid type (citric versus lactic) on lethality. For both all-beef and venisoncontaining beef snack sticks, E. coli O157:H7 reductions of approximately 3 log cycles (99.9%) were observed when product internal temperature reached 148 and 155ºF. Reductions increased to more than 5 log cycles after 2 hours of slow drying in which the smokehouse temperature was sequentially decreased to 70°F. Encapsulated citric acid was slightly more effective at lowering product pH, compared with the encapsulated lactic acid. Similar pathogen reductions were observed with 10 and 25% fat content. This study demonstrates that the defined processing schedule used to manufacture beef and venison-containing beef snack sticks is adequate to provide microbiologically safe products and to meet USDA guidelines for pathogen reduction. The processing schedule must include an extended drying phase, in addition to the thermal step, to meet these requirements.