Abstracts - January 2005

Food Protection Trends

Abstracts - January 2005

Guidelines for Listeria Testing of Environmental, Raw Product and Finished Product Samples in Smoked Seafood Processing Facilities

Single and Sequential Treatment of Beef Tissue with Lactic Acid, Ammonium Hydroxide, Sodium Metasilicate, and Acidic and Basic Oxidized Water to Reduce Numbers of Inoculated Escherichia coli O157:H7 and Salmonella Typhimurium

Guidelines for Listeria Testing of Environmental, Raw Product and Finished Product Samples in Smoked Seafood Processing Facilities

Virginia N. Scott,1* Martin Wiedmann,2 Doris Hicks,3 Robert Collette,4 Michael L. Jahncke,5 and Ken Gall 6

1-National Food Processors Association, Washington, D.C. 20005, USA;
2-Department of Food Science, Cornell University, Ithaca, NY 14853, USA;
3-University of Delaware Sea Grant College Program, Lewes, DE 19958, USA, 4-National Fisheries Institute, McLean, VA 22102, USA; 5-Virginia Seafood Agricultural Research and Extension Center, Hampton, VA 23669, USA; 6-New York Sea Grant and Cornell Cooperative Extension, Stony Brook, New York 11794, USA

SUMMARY

The Smoked Seafood Working Group (SSWG), a collaboration of two US industry trade organizations, smoked seafood processors and academia, developed guidelines for controlling Listeria monocytogenes in smoked seafood operations. To minimize the potential for L. monocytogenes contamination of finished products, it is necessary to have sanitation procedures that prevent contamination of product contact surfaces and eliminate niches where L. monocytogenes can become established, grow, and persist. Environmental testing can be used to help identify problem areas or locate contamination sources in the plant, and to confirm that problem-solving procedures have been effective. Raw seafood and finished product testing can be used to evaluate raw product suppliers and verify the effectiveness of control procedures. Regular testing can also help to track performance over time and identify new sources or reservoirs of contamination in the processing plant environment. This paper describes considerations for developing effective environmental and product testing programs for L. monocytogenes and provides four examples to illustrate how testing programs could be structured for various types of smoked seafood processors.

J. D. Stopforth, L. V. Ashton, P. N. Skandamis, J. A. Scanga, G. C. Smith, J. N. Sofos, and K. E. Belk*

Department of Animal Sciences, Colorado State University, Fort Collins, Colorado 80523-1171, USA

SUMMARY
This study was conducted to determine if several potential decontamination intervention solutions, applied either singly or sequentially onto beef tissue, could effectively reduce numbers of inoculated Escherichia coli O157:H7 and Salmonella Typhimurium. Samples (5¥2.5¥1 cm) of boneless beef plates were inoculated (ca. 10⁵ CFU/cm²) with four-strain composites of E. coli O157:H7 or S. Typhimurium and dipped (5 pieces in 1.5 l for 30 s at 23°C, unless otherwise indicated), either singly or sequentially into all possible combinations of two of the following solutions: acidic oxidative water (AOW; 0.005%, pH 2.67); basic oxidative water (BOW; pH 11.21); lactic acid (LA; 2.5%, pH 2.12 at 55ºC); ammonium hydroxide (AH; 0.1%, pH 10.89); sodium metasilicate (SM; 4%, pH 12.35 at 82°C); or distilled water (W, pH 7.01). In phase II, an approach incorporating sequential treatments that could be applied in commercial beef harvesting plant multiple-hurdles systems was evaluated. That system included sequential dipping in 1% SM (82°C), hot (82°C) water, and 5% LA (55°C), followed by 5% LA (55°C) after 48 h (at -3ºC for 10 h and 1°C for 38 h) of simulated carcass spray-chilling (by overhead misting of the inoculated product surface every 30 min for the first 10 h by use of a handheld sprayer). Additional systems ranged from no dipping steps to four sequential dipping steps using combinations of 1% SM (82°C), 5% LA (55°C), warm (55°C) or hot (82°C) water. Treatments, individual or in combinations, W, AOW, BOW or AH resulted in minimal decontamination (0.1–0.4 log CFU/cm²) compared with treatments using 2.5% LA at 55°C and 4% SM at 82°C. In general, pathogen reductions via the multiple-hurdles approach were separated into two groups with respect to efficacy: those treatments with one or more hot (82°C) application or a single 5% LA application were less effective than those combining two 5% LA applications or at least one hot (82°C) and one 5% LA application.