IAFP 2009 Program Book and Abstract Book - AB24

T1-03 Evaluating the Potential for Translocation of Listeria monocytogenes from Floor Drains to Food Contact Surfaces DSC in the Surrounding Environment Using Listeria innocua as Surrogate JASDEEP K. SAINI, James Marsden, Daniel Fung and Beth Ann Crozier-Dodson Kansas State University, Animal Science and Industry, Manhattan, KS, USA Introduction: Floor drains in processing environments harbor Listeria spp. due to continuous presence of humidity and organic substrates. The cleaning and washing activities undertaken in the processing facilities may translocate the bacterial cells from the drain into the surrounding environment thus contaminating food products being produced. Purpose: This study evaluates the potential for translocation of Listeria monocytogenes from drains to food contact surfaces in the surrounding environment using Listeria innocua as a surrogate. Methods: A 7 × 7 × 8 foot flexi-glass chamber was built in which a cast iron drain mounted on an aluminum cabinet was placed. Stainless steel coupons (6.4 × 1.9 × 0.1 cm, 12 per height) were hung at 3 different heights 1, 3 and 5 feet inside the chamber. The drain was inoculated with meat slurry (10 g ground beef/liter water, and 6 to 7 log CFU/ml of L. innocua four strain cocktail) and a commercial cleaner and a sanitizer was used. Cell translocation from the drain onto the coupons due to aerosols generated during cleaning and washing of drain was studied. Coupons were incubated in Listeria enrichment broth for 48 h. Turbid broths were streaked onto modified oxford medium (MOX) agar. Typical colonies that appeared on MOX plates were confirmed using VIP Listeria rapid test. For statistical analysis, Single Factor Model with binomial distribution was used and data were analyzed using GENMOD procedure in SAS. Results: Significantly higher translocation (P < 0.05) was seen at 1 foot (up to 25%), followed by 3 feet (up to 11%) and 5 feet (up to 2.7%) indicating that the closer the surface from the drain, the greater the number of bacterial cells that transfer from the drain to the surrounding surfaces. Significance: Results show that L. monocytogenes may translocate from drain to food contact surfaces via aerosols generated due to cleaning and washing, thus contaminating food products. T1-04 Sanitizing Efficacy on Sessile and Planktonic Listeria monocytogenes Cells CRISTINA D. CRUZ, Anthony N. Mutukumira, Fiona McKenzie and Graham C. Fletcher New Zealand Institute for Plant & Food Research, Food & Health, Auckland, New Zealand Introduction: Bacterial attachment and the subsequent biofilm formation on various environmental surfaces in food manufacturing is an important contributor to Listeria monocytogenes contamination of final food products. Even with intensive sanitation regimes, biofilms containing L. monocytogenes can remain on environmental surfaces, resulting in increased resistance to chemical sanitizers. Purpose: The objective of this study was to assess the bactericidal concentration of 24 sanitizing agents against 20 L. monocytogenes strains. Methods: All strains were inoculated in tryptic soy broth containing 0.6% of yeast extract. Planktonic cells were incubated for 24 h at 37°C and biofilms for 48-h at 30°C. Biofilms were rinsed with water to remove non-attached cells. Sanitizers were diluted in hard water (200 ppm), using the manufacturer’s instructions. Experiments were conducted in microtitre polystyrene plates. Results: The results showed that all sanitizers were effective against planktonic L. monocytogenes cells at the manufacturer’s recommended concentrations. With respect to L. monocytogenes biofilms, only the peroxyacetic acid, chlorine dioxide and acidified chlorine-based sanitizers were able to achieve a 5 log reduction of viable bacterial cells at the recommended concentrations after 5 minutes of contact time. Independent of the PFGE profile, serotype, ability to form biofilm or source (human, environment or food) of the isolates, they all showed similar responses to the sanitizers. Significance: This study suggests that biofilms are more sensitive to certain chemicals with high oxidizing power. No relationship was observed between the chemical susceptibility of the isolates and the other intrinsic characteristics investigated. T1-05 Efficiency and Optimization of UV Exposure to Reduce Listeria monocytogenes Contamination DSC on Conveyor Belts Made from Four Different Materials AMIT MOREY and Manpreet Singh Auburn University, Dept. of Poultry Science, Auburn, AL, USA Introduction: Listeria monocytogenes (LM) has been repeatedly isolated from foods and food processing facilities. LM can harbor on conveyor belts (CB) and disseminate on food. CB are often difficult to clean and involve rigorous sanitation programs to get rid of bacteria. Ultraviolet (UV) light has exhibited microbicidal properties on food and food contact surfaces. Disinfection efficiency of UV depends on bacterial species, their growth stage and surface of attachment. There is little published information on the use of UV to disinfect CB. Purpose: This study was conducted to determine efficiency and optimize parameters for the use of UV to kill LM on CB made of four different belting materials. Methods: A cocktail of five LM isolates (serotypes 3, 4b, 4c and strains 108M, 109) was made to give a suspension of approximately 106 CFU/mL. The suspension was inoculated on four types of CB; (1) Ronanyl DM 8/2 A2 + 04, (2) Volta FRMW-3.0, (3) Volta FRMB-3.0 and (4) Ropanyl DM. Each inoculated CB was subjected separately to UVC (254 nm) for 1 and 3 s at 5.95 mW/cm2 and 5.53 mW/cm2. Effect of bacterial age on disinfection efficiency was determined by exposing 12 h and 24 h old culture suspensions for 1, 3 and 5 s at 3.83 mW/cm2 and 3.52 mW/cm2 intensities on one type of belt (CB1). Analysis was conducted in triplicates and results analyzed using SAS. Results: LM count was significantly reduced on all the belts irrespective of energy intensities and time of exposure. No bacterial colonies were recovered on exposure of CB1 and 2 for 3 s at an energy intensity of 5.93 mW/cm2 CB 1 and 2 exposed to 5.95 mW/cm2 showed a higher survival (0.85 to 2.29 log CFU/cm2) as compared to 5.93 mW/cm2. CB 4 showed a survival of 1.62 to 2.39 log CFU/cm2. Maximum reduction in LM count (2.1 log CFU/cm2) was observed in 12 h culture at 3 and 5 s at 3.83 mW/cm2. Significance: UV can be effectively used to reduce the risk of LM contamination via CB. 24 — Abstract Book Technical

IAFP 2009 Program Book and Abstract Book

Table of Contents for the Digital Edition of IAFP 2009 Program Book and Abstract Book