Listeria Monocytogenes in fresh cheeselets.

Abstract

Human listeriosis, the disease caused by the bacterium, has been previously linked to the consumption of cheeses. A study carried out in Portugal to detect and characterize L. monocytogenes in cheese production, established that although L. monocytogenes was not detected in cheese samples, 2 of 105 samples of raw milk destined to be used for cheese production were tested positive for Listeria monocytogenes. The isolates represented a ribotype that previously was linked to multiple human listeriosis outbreaks. The study also showed that during the ripenening of cheese, the physicochemical properties allowed the growth and the survival of L. monocytogenes (Kongo et al, 2006). Another study concluded that 6.3% of tested Latin-style Fresh cheese samples were found contaminated with L. monocytogenes. The most common isolated ribotype was previously linked to a multi state human listeriosis outbreak in the United States in 1998. According to this study, listeriosis outbreaks were previously linked to Latin-style fresh cheese made from unpasteurised milk, however the presence of the organism in pasteurized cheese products illustrates that persistent environmental contamination also represents an important source of finished product contamination (Kabuki et al, 2004).

The aim of this dissertation is to establish whether locally produced Fresh Cheeselets can be considered safe from Listeria Monocytogenes. It should be kept in mind that results obtained from this study cover only the period when the study was carried out and is not a reflection of the past or the future.