The effect of food conditioning films on the attachment of Listeria monocytogenes to food contact surfaces
LE3 .A278 2013
Bachelor of Science
Listeria monocytogenes is a Gram-positive bacterium that is one of the most commonly detected foodborne pathogens resulting in food recalls. Listeriae are problematic for the food processing industry as they can survive harsh environmental conditions through the formation of biofilms. Since L. monocytogenes is capable of growing at refrigeration temperatures, surviving cells of this pathogen residing in biofilms can reach dangerous levels on foods or food contact surfaces. I investigated the effects different food-conditioning films have on the attachment of L. monocytogenes 568 (Lm 568; serotype 1/2a) and L. monocytogenes 21F10 (Mutant) to several surfaces relevant to those found in dairy processing environments (polycarbonate, Buna-N rubber, silicone rubber, stainless steel). The attachment trials were conducted under static conditions using CDC biofilm reactors containing small circular coupons (standardized dimensions) consisting of the test materials. In order to coat the surfaces with dairy-related food films, the coupons were first submerged in different dairy-related solution/suspensions for 20-24 hours. The reactors were drained and the coupons gently washed with sterile water. The bioreactors were then refilled with a suspension of Lm 568 cells and incubated at room temperature for two hours to allow for attachment. After the bioreactors were emptied, the coupons were washed with water and the bacteria from each coupon were enumerated. My results showed that not only does the type of surface affect attachment, but also certain food coatings can either reduce or promote attachment. By understanding how certain food film coatings inhibit bacterial attachment to surfaces found in a food processing plant environment, it may be possible to treat or design food contact surfaces that deter biofilm and/or make sanitization procedures more efficient.
The author grants permission to the University Librarian at Acadia University to reproduce, loan or distribute copies of my thesis in microform, paper or electronic formats on a non-profit basis. The author retains the copyright of the thesis.