HEAT RESISTANCE IN LIQUID EGGS OF SOME STRAINS OF THE GENUS SALMONELLA ^a,b

Abstract

Thermal destruction of the Salmonella group of micro-organisms, which are commonly present in commercially broken out raw egg pulp, is the prime objective of pasteurizing liquid egg in the manufacture of frozen and dried egg products. It is clearly recognized from Salmonella pathogenicity studies by McCullough and Eisele (24,25,26,27) and from other public health investigations that there is a need f o r eliminating these offending bacteria from egg products in order to prevent the occurrence of salmonellosis in institutional and 'military feeding and to minimize the latent "carrier state" of infectiousness, particularly among the food handlers. Adequacy of pasteurization depends on many factors, such as numbers and types of Salmonella present in the raw material, the pH of the liquid egg, and the time-temperature relationships involved in the heat resistance of these bacteria.Thermal process evaluations for food sterilization were established on a scientific basis in 1920 following the classical paper by Bigelow, Bohart, Richardson, and Ball (7). The ensuing three decades have brought many improvements in the technique of heat resistance determinations (1, 8, 14, 34, 37, 43, 4 8 ) and in the mathematical treatments of the thermal death time data secured (2, 3, 4, 7, 15, 16, 17, 20, 21, 22, 30, 32, 38, 39, 44, 45, 46). Although the literature concerning the thermal resistance of bacterial spores is rich in these advances, it is unfortunate that the same principles have not been as widely adopted by bacteriologists studying the Bansporulating organisms. I n connection with their investigation of t h e m 1 death time curves of coliform bacteria in milk, Olson, Macy, and Halvorson (29) stated recently: "With few exceptions the data on the thermal destruction of non-spore-forming bacteria are of such a nature that thermal death-time curves for the organisms studied cannot be constructed." A thermal death time curve defines the heat resistance of an organism at a given temperature (F value) as well as its sensitivity to changes in temperature ( z value). Such a curve, however, assumes the existence of absolute time-temperature relationships for the total destruction of a particular bacterial concentration. Hence, a sufficient change in the initial population of the suspension undergoing heat treatment would produce a change in the properties of the "absolute" thermal death time curve. A

Effective Heat Processing for the Destruction of Pathogenic Bacteria in Turkey Rolls

“…These results are in agreement with those of Anellis et al (1954). They reported that heating perishable foods (custard, chicken a la king and ham salad) to 150°F.…”

Combined effects of heat, acetic acid, and salt for inactivating Escherichia coli O157:H7 in laboratory media

“…A similar synergistic effect of low pH on heat treatment has been observed with the inactivation of E. coli O157:H7 and S. enteritidis in buffer (Teo, Raynor, Ellajosyula, & Knabel, 1996), Salmonella in liquid whole egg (Anellis, Lubas, & Rayman, 1954) and L. monocytogenes in beef gravy (Juneja & Eblen, 1999). In fact, temperature is a primary factor influencing organic acids activity and there are several studies reporting that increasing temperature increased the effectiveness of organic acids (Brudzinski & Harrison, 1998;Presser, Ross, & Ratkowsky, 1998;Uljas & Ingham, 1998).…”

Kinetics Model Comparison for the Inactivation ofSalmonellaSerotypes Enteritidis and Oranienburg in 10% Salted Liquid Whole Egg

“…Our third isolate (Salmonella serotype Oranienburg DD2229) was originally provided by Dupont from their Salmonella library ( Jensen and Hubner, 1996). Salmonella serotype Oranienburg is, historically, a common strain of Salmonella used for LE pasteurization studies (Gibbons and Moore, 1944;Schneider, 1946;Solowey et al, 1946;Winter et al, 1946;Cantor and McFarlane, 1949;Solowey et al, 1949;Anellis et al, 1954;Cotterill, 1968;Cotterill and Glauert, 1969;McBee and Cotterill, 1971;Cotterill and Glauert, 1972;Cotterill et al, 1973). The estimated asymptotic z-value of Salmonella in 10% SLWE is 11.5°C (standard error = 2.1°C), which is approximately 85% higher than the 6.2°C reported by Jung and Beuchat (2000), while our estimated asymptotic D-values are also larger ( Table 2) than these authors reported.…”