Amongst the Listeria species, only Listeria monocytogenes is considered to be a significant human and animal pathogen, and is distinguished by its ability to cause hemolytic activity, which is usually tested with conventional sheep blood agar plates (Perrin and others 2003). This indicates a risk where they are present in food products, and are more prevalent in ready-to-eat (RTE) meat and poultry products. Being ubiquitous in the environment and in food, Listeria innocua is considered to be a nonpathogenic bacterium (Perrin and others 2003). However, L. innocua is important because it possess many characteristics of the foodborne pathogen L. monocytogenes but is non-pathogenic in character, therefore making it favorable to be tested as a …show more content…
In order to detect the potential growth and the maximum growth rate of L. innocua, performing experimental inoculation challenge tests is essential to determine the efficacy of various preservatives on various microorganisms, including the Listeria species. These experiments can validate the lethality of certain treatments on foodborne microbes and benefit the food industry by finding methods to prolong shelf life of refrigerated and ambient temperature stored food products. One of the common treatments include the usage of nisin, which is one of the most effective natural compounds against the growth of Gram positive bacteria. The objectives of this experiment was to learn experimental inoculation challenge studies in food microbiology; to learn about inoculum preparation, the level of inoculum, and food product inoculation; and to study the effect of surface application of nisin on the growth and survival of L.