Purpose: The goal of this study was to determine if traditional processing (fermentation and drying; no heat step) would result in a 5 log CFU/g reduction of Escherichia coli O157:H7 (EC), Listeria monocytogenes (LM) and Salmonella Typhimurium (ST) in experimentally-inoculated Landjäger.
Methods: Pre-seasoned meat batter (4°C) containing pork, beef, and a commercial starter culture (Pediococcus acidilactici, P. pentosaceus, Staphylococcus carnosus, S. xylosus, and Lactobacillus sakei), was obtained from a sausage processor. The meat batter was divided proportionally and inoculated with individual pathogens or a pathogen cocktail of EC, ST, and LM. A negative control was made by inoculating sausage batter with 0.1% sterile buffer. Sausage links (~50 g each) were formed, pressed, fermented (24°C, for 72 h to pH ~4.8), cold smoked, and dried to a water activity of 0.88. Sausages were vacuum packaged in 3 mil plastic barrier film pouches and stored up to 20 days at ~23°C. Two sausages per treatment were randomly selected at each time point for microbial analysis, pH measurements, and water activity.
Results: Results suggest that fermentation and drying alone could reduce the pathogens > 3 log. LM was reduced 5.5 and 5.3 log CFU/g in individual- and cocktail-inoculated sausages, respectively. Similarly, ST was reduced 5.6 and 4 log CFU/g in individual- and cocktail-inoculated sausages, respectively. However, the process only achieved a ~4 and 3 log CFU/g reduction of EC in individual- or cocktail-inoculated sausages.
Significance: This study is the first to demonstrate that traditional processing of Landjäger, without a heat step, may result in a safe product. Future studies will address the impact of the traditional fermentation process on sausages made with all-pork formulations.