Thermal Resistance of Salmonellae and Staphylococci in Foods

Abstract

The heat-resistant Salmonella senftenberg 775W and two strains of Staphylococcus aureus were tested at temperatures up to 68.3 C (71.1 C for S. senftenberg) in four different media. From the survival data, decimal reduction times (D values) were calculated for each set of conditions, and decimal reduction time curves were constructed for each bacterial strain in each medium. Slopes of decimal reduction time curves (ZD) ranged from 4.52 to 6.38 C with a single exception. There was no statistical heterogeneity among the remaining values. Results were in close agreement with published results of similar studies conducted at somewhat lower temperatures and support the practice of using a slope value (ZD) of 5.56 C for establishing time-temperature relationships for food processing. It is recommended that such a decimal reduction time curve not be extrapolated to temperatures more than 5.56 C higher than those actually tested. Modern technology has made available many new food products, frozen, canned, or dried, both cooked and uncooked. The wide distribution of many of these products, with their increasing use for quantity service in cafeterias and large

Effect of combined ultrasonic and heat treatment (thermoultrasonication) on the survival of a strain ofStaphylococcus aureus

“…It can be seen that Z-values are dependent on the suspension medium. The Z-values for the heat treatment are in general agreement with those found by Thomas et al (1966). Figs 1 and 2 show the Arrhenius plot of each treatment.…”

The heat resistance of Listeria monocytogenes

“…Based on the ST model, L. monocytogenes is substantially more heat-resistant than common Salmonella serotypes but less resistant than S. senfenberg 775W (D values at 62.8"C are 46, 5 and 126-228 s respectively; Read et al. 1968;Thomas et al 1966).…”

Recovery of Staphylococcus aureus in Gray Mugil cephalus Roe (Bottarga): Investigation by an Integrated Cultural/Molecular Approach

“…These virulence factors can induce gastroenteric syndrome and toxic shock syndrome (Wilson and others ; Walden and others ; Pereira and others ). In this circumstance, bottarga manufacturing could be a possible cause of bacterial contamination in different attendant situations: (i) considerable manual work, (ii) S. aureus salt and temperature resistance (Thomas and others ), (iii) temperatures in bottarga work processing, ranging from 0 to 30 °C.…”