Research Article

The survival of listeria monocytogenes in yoghurt and ice cream

Saadia H. Elshinaway, Arafa M.S. Meshref, Mohamed M.A. Zeinhom and DaliaA. A. Hafez
Department of Milk hygiene, Faculty of Veterinary Medicine, Beni-Suef University, Beni-Suef 62511, Egypt

Abstract

The ability of L. monocytogenesas an opportunistic pathogen of humans and animals, to survive and growunder various adverse environmental conditions, makes it a potential health hazard afterthe consumption of contaminated dairy products, it often implicated in several outbreaks of listeriosis. This study was conducted to investigatethe survival of L. monocytogenes strain (NCTC13372)wheninoculated with a population level of 6.95 log cfu/g and 7.64 log cfu/g and stored at 4ºC for 15 days and 3 months at -18ºC for yoghurt and ice cream respectively. The obtained results indicatedthat complete inactivation of the tested organism wasn’t achieved till the end of storage periods and the inoculated L. monocytogenes wassurvived in both yoghurt and ice cream throughout thetrial. It is concluded that in the dairy industry, we cannot rely upon either fermentation process and storage at refrigerating temperature or upon storage at freezing temperature during yoghurt and ice cream manufacturing tocontrol L.monocytogenes pathogen in order to provide safe products for consumption.

Keywords

survival, listeriamonocytogenes,