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United States Department of Agriculture

Agricultural Research Service

Research Project: VALIDATION OF THE EFFECT OF INTERVENTIONS AND PROCESSES ON PERSISTENCE OF PATHOGENS ON FOODS Title: Effectiveness of fermentation/drying and post-process pressurization on viability of Listeria monocytogenes and Salmonella spp. in Genoa salami

item Call, Jeffrey
item Porto-Fett, Anna
item Shoyer, Brad
item Pshebniski, C. - SANTA MARIA FOODS
item Cocoma, George - PROFESSIONAL RES. CO.
item Luchansky, John

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: January 29, 2009
Publication Date: July 12, 2009
Citation: Call,J.,Porto-Fett,A.,Shoyer,B.,Pshebniski,C.,Cocoma,G.,Luchansky,J. 2009.Effectiveness of fermentation/drying and post-process pressurization on viability of Listeria Monocytogenes and salmonella spp. in Genoa salami [abstract].IAFP.Grapevine,TX. p.1.

Technical Abstract: We evaluated the effectiveness of fermentation and drying alone and in combination with high pressure processing (HPP) to inactivate five-strain cocktails of L. monocytogenes or Salmonella spp. (ca. 7.0 log10 per gram of each in batter) in Genoa salami. The inoculated chubs were fermented at 20 degree C for 6 hours and 27 degree C for 26 hours and then dried at 20 degree C for 40 hours and 17 degree C: i) for 25 days (65 mm casing; aw 0.883 +/- 0.014) or 35 days (105 mm casing; aw 0.917 +/- 0.006), or ii) to a target aw of 0.920 that was attained in 11 to 13 days (65 mm casing; aw 0.920 +/- 0.041), or iii) to a target aw of 0.940 that was attained in 20 to 24 days (105 mm casing; aw 0.939 +/- 0.006). After drying, four chubs in each of two trials for each treatment were post-processed pressurized at 70,000 (483 mPa) or 87,000 (600 mPa) psi for 0 to 12 min. Following HPP chubs were cut into quarters, after which some were sampled for the pathogen while others were vacuum sealed and stored at 4 degree C. The extent of inactivation of L. monocytogenes and Salmonella after fermentation/drying ranged from 1.0 to 1.62 and 3.5 to 4.5 log10 CFU/g, respectively. Following HPP, numbers of Salmonella were reduced by ca. an additional 2.5 log10 CFU/g within 1 and 5 min at 87,000 psi and 70,000 psi, respectively, whereas an additional decrease of ca. 3.0 and 5.0 log10 CFU/g was achieved after 5 min at 70,000 psi and 3 min at 87,000 psi, respectively, for L. monocytogenes. After 28 days at 4 degree C L. monocytogenes levels decreased by ca. an additional 0.61 to 1.7 log10 CFU/g, whereas a decrease of ca. 0.5 log10 CFU/g was observed for Salmonella. Thus, fermentation/drying and/or HPP as a post-process intervention can appreciably reduce the levels of L. monocytogenes and Salmonella in Genoa salami.

Last Modified: 10/23/2014
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