Pasteurize deli turkey products to reduce L. monocytogenes.

Deli turkey products have been part of the largest deli poultry recalls in U.S. history. Increased testing by the USDA Food Safety Inspection Service to find the source of outbreaks and deaths in the United States has implicated L. monocytogenes contamination in several deli turkey products.

Scientists at Oklahoma State University investigated the pasteurization of pre-packaged, post-packaged and combination pre-post-packaged deli turkey products. They wanted to find a way to reduce potential L. monocytogenes surface contamination that could come from environmental contamination or worker handling. The researchers determined that the surface pasteurization of ready-to-eat (RTE) processed meats could alleviate product contamination and the potential for recalls. Deli products are prone to acquiring contamination during the final packaging steps.

A radiant heat oven and temperature-controlled water bath were used for pre-package, post-package and combination pre-post-package pasteurization of four types of deli turkey products: roast, pepper-seasoned, skin-on and oil-browned turkey. The samples were contact-inoculated with four strains of L. monocytogenes.

Using either a 60-second or 75-second pre-package pasteurization process, the scientists obtained 1.6 to 3.4 [log.sub.10] or 2.25 to 4.2 [log.sub.10] reductions of L. monocytogenes, respectively, for the products. Similarly, using either a 2-minute or 3-minute post-package pasteurization process, the researchers obtained 1.75 to 2.9 [log.sub.10] or 2.2 to 3.6 [log.sub.10] reductions in microbial levels, respectively.

However, when using only a 1-minute pre-package and 1-minute post-package pasteurization process at 200 F, researchers obtained 3.5 to 4.1 [log.sub.10] reductions in the levels of L. monocytogenes.

In addition, the scientists examined the utility of thermal imaging as a way to obtain hundreds of surface temperature measurements of pasteurized products. The problem is cost. One thermal imaging camera they initially examined cost about $35,000 to 40,000, so that might be expensive for even large processors.

But the concept was interesting in what it could do. Every computer pixel in the digital record became a temperature monitoring event. You could cover a wide area of product with thousands of measurements instead of making just a few pin-point measurements as you do with hand-held infrared guns that shine a few beams and measure the surface temperatures at just a few points in a product. Further information. Peter M. Muriana, Oklahoma State University, Food and Agricultural Products Center and Department of Animal Sciences, 109 FAPC Building, Monroe St., Stillwater, OK 74078; phone: [phone]; fax: [phone]; email: [e-mail].