Heat‐Resistance of Escherichia Coli O157:H7 in Meat and Poultry as Affected by Product Composition

Abstract

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.

Effectiveness of Composting Road-Killed Deer In New York State

“…1981, Graven and Blankenship 1983, Mitscherlich and Marth 1984, Doyle and Schoeni 1984, Ahmed, et al 1995, Junega, et al 1995, Lihono, et al 2003, Murphy, et al 2004, Price and Tom 2005. Most of the pathogens found in road-killed deer appear to be fairly easily killed by temperatures above 60°G, so in order to assess the effectiveness of destruction of pathogens due to composting, it was decided that hardier indicator organisms should be used.…”

Heat Inactivation of Mycobacterium avium subsp. paratuberculosis in Aseptically Prepared Ground Beef

“…The D-values we obtained for E. coli were different but the organism we used was not a pathogenic strain. The calculated Dvalues obtained were lower in the case of Doyle and Schoeni (1984), higher compared to Ahmed et al (1995) and higher at 51.7 and 57.2 °C but lower at 62.7 °C compared to the results obtained by Line et al (1991). Differences in meat composition, strains and devices used for the heat treatment (laboratory test tube vs. Whirl-pak TM sampling bag) are likely to account for such differences.…”

“…It is less variable than the D-value and usually reaches between 4 and 7 °C for vegetative cells and 10 °C for bacterial spores (Mafart, 1991;Brennan, 2006). For enterohemorrhagic E. coli, Ahmed et al (1995) obtained a z-value of 4.78 °C in ground meat with 7% fat and Line et al (1991) obtained 7.3 °C in ground meat with 2% fat, with both using laboratory test tubes for the experiment, whereas Juneja et al (1997) obtained a zvalue of 6.0 °C using a Whirl-Pak™ sampling bag. In pork mixed with salt and nitrite, Houben (2003) obtained a z-value of 10 °C for E. facaelis, which is higher than our results (Table 2).…”

“…As the temperature increased, the Dvalue decreased significantly for each microorganism studied (Table 3). Doyle and Schoeni (1984), Ahmed et al, (1995) and Line et al (1991) evaluated the Dvalue of enterohemorrhagic E. coli in ground beef and they observed a reduction in D-value with temperature increase. The D-values we obtained for E. coli were different but the organism we used was not a pathogenic strain.…”

“…The slightly higher fat content and the difference in E. coli strains would likely explain the higher values they obtained at 55, 60 and 65 °C. Fat is known to protect the cell by reducing the water activity and thermal conductivity of the matrix (Ahmed et al, 1995;Doyle and Schoeni;1984). Furthermore, constituents of the food matrix can absorb part of the heat which reduces heat transfer to the cells (Gordon and Ahmad, 1991;Marcotte et al, 2008).…”