THERMAL AND BIOLOGICAL TREATMENTS TO CONTROL PSYCHROTROPHIC PATHOGENS

Over the past decade, advances in egg processing technologies have per mitted commercial production of ultrapasteurized liquid whole egg (LWE ) products with a shelf-life of greater than 10 wk at 4 C. The inactiv ation and control of psychrotrophic pathogens such as Listeria monocyt ogenes and Aeromonas hydrophila in extended shelf-life LWE and convent ionally pasteurized egg products is an ongoing food safety concern. Th is manuscript reports on the common features of these two psychrotroph ic pathogens, their incidence in egg products, and their survival, gro wth potential, and heat resistance in liquid egg. Furthermore, this ma nuscript reports in detail on the results of two specific studies cond ucted in our laboratory whose objectives were: 1) to determine the hea t resistance (D-values) of A. hydrophila in LWE using a low-volume imm ersed sealed glass capillary tube (ISCT) procedure; 2) to assess the i mpact of methodology (i.e., ISCT procedure vs a conventional capped te st tube procedure) on the apparent thermal resistance of A. hydrophila ; and 3) to report on the use of the bacteriocin nisin to restrict the survival of L. monocytogenes in ultrapasteurized LWE stored at refrig eration temperatures.