Survival of Listeria monocytogenes during Storage of Ready-to-Eat Meat Products Processed by Drying, Fermentation, and/or Smoking

Abstract

The survival of Listeria monocytogenes was evaluated on 15 ready-to-eat meat products made using drying, fermentation, and/or smoking. The products were obtained from six processors and included summer sausage, smoked cured beef, beef jerky, snack stick, and pork rind and crackling products. The water activity of the products ranged from 0.27 (pork rinds and cracklings) to 0.98 (smoked cured beef slices). Products were inoculated with a five-strain cocktail of L. monocytogenes, repackaged under either vacuum or air, and then stored either at room temperature (21ЊC) or under refrigeration (5ЊC) for 4 to 11 weeks. Numbers of L. monocytogenes fell for all products during storage, ranging from a decrease of 0.8 log CFU on smoked cured beef slices during 11 weeks under vacuum at 5ЊC to a decrease of 3.3 log CFU on a pork rind product stored 5 weeks under air at 21ЊC. All of the products tested could be produced under alternative 2 of the U.S. Department of Agriculture regulations mandating control of L. monocytogenes on ready-to-eat meat and poultry products. For many of the products, 1 week of postprocessing storage prior to shipment would act as an effective postlethality treatment and would allow processors to operate under alternative 1 of these regulations.On 6 June 2003, the U.S. Department of Agriculture (USDA) published an interim final rule addressing the control of Listeria monocytogenes on ready-to-eat (RTE) meat and poultry products (2). This rule went into effect 6 October 2003 and has already had a major effect on processors of these products. The rule is intended to encourage processors of RTE products to take one or more specific steps to ensure the absence of L. monocytogenes from their products. These steps range from focused sanitation steps to formulation or processing steps designed to kill L. monocytogenes or inhibit its growth. The processor is also required to test for L. monocytogenes or Listeria spp. on food-contact surfaces in the area of the plant in which RTE products are handled after cooking. The amount of testing is related to the type of RTE product, product ingredients, and how the products are processed and handled. In particular, the rule requires processors of RTE meat and poultry products to adopt one of three designated alternatives for control of L. monocytogenes on their products. The alternatives involve various levels of control and microbiological testing. Under alternative 1, the processor uses a postlethality treatment that reduces or eliminates L. monocytogenes and uses an antimicrobial agent or process that suppresses or limits L. monocytogenes growth throughout product shelf life. Under alternative 2, the processor uses either a postlethality treatment that reduces or eliminates L. monocytogenes or uses an antimicrobial agent or process that suppresses or limits L. monocytogenes growth through-* Author for correspondence. Tel: 608-265-4801; Fax: 608-262-6872; E-mail: scingham@wisc.edu.out product shelf life. Under alternative 3, only sanitation measures are rel...

Listeria monocytogenes on cured meat products. A case study on Speck (a typical Italian smoked ham) according to EC Regulation 2073/2005

“…In agreement with previous studies carried out on Italian dry cured meat products (Grisenti et Similar findings were reported for other European and US typical meat products (Ingham et al 2004;Dourou et al 2009). In other terms, the combination of salting, smoking and drying as practiced with the Italian Speck can be considered an effective antilisterial process (Mittich et al 2009) as there was no growth of the pathogen when it was inoculated at post-lethality stages and stored at either refrigeration temperature or room temperature.…”

Health and Safety Considerations of Fermented Sausages

“…In general, enhanced reductions were obtained in products with low pH and low and stored under ambient conditions [103,116,155]. Reductions of L. monocytogenes during fermentation and drying in fermented sausages are dependent on many factors, including strain differences in their ability to tolerate and adapt to DFS conditions that are also dependent on recipe and processing conditions [147,156].…”

Behavior of Listeria monocytogenes type1 355/98 (85) in meat emulsions as affected by temperature, pH, water activity, fat and microbial preservatives

“…Listeria spp. has been found in a great variety of meats and meat products, even in sausages (Ingham, Beuge, Dropp, & Losinski, 2004;Jonson, Doyle, & Cassens, 1990).…”