Food Protection Trends - November 2008 - (Page 760)

ARTICLES Copyright© 2008, International Association for Food Protection 6200 Aurora Ave., Suite 200W, Des Moines, IA 50322-2864 Food Protection Trends, Vol. 28, No. 11, Pages 760–764 Biofilm Formation of Listeria monocytogenes on Various Conveyor Belt Surfaces SHANKAR PITCHIAH, CHRISTINE Z. ALVARADO* and MINDY M. BRASHEARS Dept. of Animal and Food Sciences, Texas Tech University, Box 4214, Lubbock, TX 79409, USA INTRODUCTION SUMMARy Biofilm formation depends on many factors, including the number of bacteria and the amount of debris lodged on processing belts during production. This study compared different processing belts and mesh sizes (stainless steel single-loop 80% mesh, stainless steel balance-weave 70% mesh, polypropylene meshtop 24% mesh, polypropylene 48% mesh, acetal 3.2% mesh, and polyurethane with monoester polyethylene fabric-canvas < 1% mesh) with regard to their effects on the ability of Listeria monocytogenes to form biofilms. This important information can be used in selecting conveyor belts for environments in which ready-to-eat products are produced. Biofilms were formed on test surfaces of each belt over 2, 3 and 4 days in Trypticase Soy Broth at 10ºC. Surface attached cells were removed by agitation and the numbers of attached cells were determined on Brain Heart Infusion Agar. Variation of belt size and mesh (%) were normalized to per-square-centimeter surface area. After 2 days, biofilm formation was least on the stainless steel single loop, followed by stainless steel balance weave, canvas, polypropylene, polypropylene-meshtop, and acetal. After 3 days, biofilm formation was greatest on both acetal and canvas belts compared with that on the stainless balance-weave. By day 4, the stainless steel single loop belt showed significantly less biofilm formation than the canvas belt, with no significant differences among the other belts. The results of this study indicate that biofilm accumulation differs with belt type. A peer-reviewed article *Author for correspondence: 806.742.2805 ext. 234; Fax: 806.742.4003 Email: christine.alvarado@ttu.edu Listeria monocytogenes causes over 2,500 illnesses and 500 deaths in the United States each year (10). Most symptoms are flu-like and occur within a few days to up to three weeks after infection (11). Healthy adults may have very few symptoms when infected. However, in immunocompromised people, the risk of death is elevated. In pregnant women, L. monocytogenes can cross the placenta and infect the fetus. This fetal infection can cause miscarriages, stillbirths, or serious medical complications such as pneumonia, meningitis, or septicemia in newborns. The mortality rates can be as high as 80% for neonatal infections and 50%–70% for meningitis and septicemia patients (11). The minimum infectious dose of L. monocytogenes is currently unknown because of the differing virulence among strains and extraneous factors such as age and health of the individual (30). L. monocytogenes is very widespread in nature. It has been known to survive extreme environmental temperatures such as refrigeration, freezing, heating, and drying. The optimum growth temperatures for L. monocytogenes is 30–37°C, but it can grow at temperatures as low as 1°C and as high as 45°C 760 FOOD PROTECTION TRENDS | NOVEMBER 2008

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Food Protection Trends - November 2008 Contents Sustaining Members Perspectives from Your President Commentary from the Executive Director Biofilm Formation of Listeria monocytogenes on Various Conveyor Belt Surfaces Third-Party Certification of Agro-Products in China:�A Study of Agro-Product Producers in Guangzhou, Shenzhen, Hangzhou and Qingdao IAFP 2008 in Review Award Winners 3M Microbiology - Black Pearl Award Winner Ivan Parkin Lecture - Russell S. Flowers John H. Silliker Lecture - Michael P. Doyle Student Travel Scholarships Session Summaries Highlights of the Executive Board Meeting Minutes of the 95th Annual Business Meeting Committee Minutes Executive Board Response to Committee Recommendations Exhibitors of IAFP 2008 Special Contributors and Sponsors Call for Awards - IAFP 2009 New Members What's Happening in Food Safety Industry Products Coming Events Advertising Index Journal of Food Protection Table of Contents Audiovisual Library Order Form Booklet Order Form Membership Application

Food Protection Trends - November 2008

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