Viability of Shiga Toxin–Producing Escherichia coli, Salmonella spp., and Listeria monocytogenes during Preparation and Storage of Fuet, a Traditional Dry-Cured Spanish Pork Sausage

Abstract

The primary objective of this study was to monitor viability of Shiga toxin–producing Escherichia coli (STEC), Salmonella spp., and Listeria monocytogenes during preparation and storage of fuet. Regarding methodology, coarse-ground pork (ca. 35% fat) was mixed with salt (2.5%), dextrose (0.3%), starter culture (ca. 7.0 log CFU/g), celery powder (0.5%), and ground black pepper (0.3%) and then separately inoculated with a multistrain cocktail (ca. 7.0 log CFU/g) of each pathogen. The batter was stuffed into a ca. 42-mm natural swine casing and fermented at 23 ± 2°C and ca. 95% ± 4% relative humidity to ≤pH 5.3 (≤48 h). Sausages were then dried at 12 ± 2°C and ca. 80% ± 4% relative humidity to a water activity (aw) of 0.89 (within 33 days) or aw 0.86 (within 60 days). A portion of each batch of fuet was subjected to high-pressure processing (HPP; 600 MPa for 3 min) before chubs were vacuum packaged and stored for 30 days at 20 ± 2°C. The results revealed that pathogen numbers remained relatively unchanged after fermentation (≤0.35 log CFU/g reduction), whereas reductions of ca. 0.8 to 3.2 log CFU/g were achieved after drying fuet to aw 0.89 or 0.86. Regardless of whether fuet was or was not pressure treated, additional reductions of ca. 2.2 to ≥5.3 log CFU/g after drying were achieved following 30 days of storage at 20°C. For non–HPP-treated fuet dried to aw 0.89 and stored for 30 days at 20°C, total reductions of ≥5.3 log CFU/g in levels of STEC or Salmonella spp. were achieved, whereas levels of L. monocytogenes were reduced by ca. 3.6 log CFU/g. Total reductions of ≥5.3 log CFU/g in levels of all three pathogens were achieved after drying non–HPP-treated fuet to aw 0.86. For fuet dried to aw 0.89 or 0.86, that were pressure treated and then stored for 30 days at 20°C, total reductions of >6.2 log CFU/g in levels of all three pathogens were achieved. In conclusion, the processing parameters tested herein, with or without application of HPP, validated that reductions of ≥2.0 or ≥5.0 log CFU/g in levels of STEC, Salmonella spp., and L. monocytogenes were achieved during preparation and storage of fuet.