Food Protection Trends - July 2012 - (Page 384)

ARTICLES Food Protection Trends, Vol. 32, No. 7, Pages 384–390 Copyright© 2012, International Association for Food Protection 6200 Aurora Ave., Suite 200W, Des Moines, IA 50322-2864 Inhibition of Listeria monocytogenes by Carnobacterium piscicola in Fresh and Pasteurized Crab Meat CARLA GUTIERREZ TYLER1, MICHAEL JAHNCKE*1,2, SUSAN SUMNER1, CAMERON HACKNEY3, RENEE BOYER1, HENGJIAN WANG1 AND TOM RIPPEN4 1 Virginia Polytechnic Institute and State University, Food Science and Technology, 22 Duck Pond Road, Blacksburg, VA 24061, USA; 2Virginia Seafood AREC, 102 S. King St., Hampton,VA 23669, USA; 3The Davis College of Agriculture, Forestry Natural Resources and Design, West Virginia University, Morgantown, WV 26506, USA; 4University of Maryland Eastern Shore, 2122 Richard A. Henson Center, Princess Anne, MD 21853, USA ABSTRACT The ability of Carnobacterium piscicola to inhibit Listeria monocytogenes at different concentration levels, storage times and temperatures was examined. Twenty-five g samples of fresh and previously pasteurized blue crab meat were placed into separate sterile 59 ml soufflé cups, inoculated with 0.1 ml C. piscicola at three different concentration levels (2, 4 and 6 log CFU/g) and 0.1 ml (log 2.0 CFU) of L. monocytogenes (ratios of 1:1, 2:1 and 3:1 of C. piscicola to L. monocytogenes). Fresh crab meat and previously pasteurized crab meat was stored at 4oC or 10oC and sampled until aerobic plate count reached ≥ 7 log CFU/g, which was considered spoilage. At each sampling time, crab meat inoculated with both organisms was plated on modified Lactobacillius deMan Rogosa Sharpe (pH 7) and modified oxford agar (MOX). Uninoculated crab meat was plated on trypticase soy agar and meat inoculated with only L. monocytogenes was plated on MOX. In both fresh and pasteurized crab meat, regardless of the inoculation levels, L. monocytogenes and C. piscicola followed similar growth trends. C. piscicola reduced growth of L. monocytogenes in pasteurized crab meat after 14 day at 4oC and 10 day at 10oC (P < 0.05). INTRODUCTION Fresh crab meat is a fully cooked product, where the crab meat is “picked” from cooked crabs, packed into plastic containers and sold refrigerated. Bacteria found in fresh crab meat are primarily the result of environmental contamination during the picking and packaging process. In coastal areas, it is not uncommon, or illegal as long as the containers do not state “Fresh Crab Meat,” for pasteurized crab meat to be repacked into cups for refrigerated sales to maintain a steady supply of crab meat products throughout the year (13). Crab processors are aware of possible contamination of crab meat by pathogens, preventing contamination by Listeria monocytogenes in fresh crab meat (ready to eat; RTE) a high priority. L. monocytogenes is a psychrotroph capable of growth at refrigeration temperatures (22). The pathogen is found in a wide variety of fish and shellfish products and can be isolated from different water sources (18). The ability of Listeria spp. to persist in the marine environment and fresh water streams, indicates that fish and other aquatic animals can be contaminated in their natural habitat (14). There is a higher incidence of Listeria spp. present in chi- *Author for correspondence: Phone: +1 757.727.4861; Fax: +1 757.727.4871 E-mail: mjahncke@vt.edu 384 FOOD PROTECTION TRENDS | JULY 2012 http://www.foodprotection.org/files/food-protection-trends/Jul-12-Gutierrez.pdf

Table of Contents for the Digital Edition of Food Protection Trends - July 2012

Food Protection Trends - July 2012
Contents
Sustaining Members
Food for Thought from Your President
Commentary from the Executive Director
Inhibition of Listeria monocytogenes by Carnobacterium piscicola in Fresh and Pasteurized Crab Meat
Gold Sustaining Member Profiles
IAFP’s European Symposium on Food Safety
New Members
What’s Happening in Food Safety
Industry Products
Award Winners
General Information
Registration Information
Special Contributors and Sponsors
Advertising Index
Coming Events
Journal of Food Protection Table of Contents

Food Protection Trends - July 2012