Title: Comparison of supplements to enhance recovery of thermally-injured Salmonella from liquid egg white Authors
|Kornacki, Jeffrey - KORNACKI MICROBIOLOGY SOL|
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: April 12, 2008
Publication Date: August 4, 2008
Citation: Gurtler,J., Kornacki, J. 2008. Comparison of supplements to enhance recovery of thermally-injured salmonella from liquid egg white [abstract].International Association for Food Proection, 95th Annual Meeting. Columbus, OH. p.1. Technical Abstract: The recovery of Salmonella from liquid egg white (LEW) is complicated by thermal and innate LEW antimicrobial-induced injury. Numerous supplements have been reported to promote the recovery of injured bacteria. The purpose of this study was to determine the efficacy of twelve media supplements to affect the recovery of heat-injured Salmonella from LEW. A five-strain composite of Salmonella was inoculated in LEW at 7.72 log CFU/ml, heated at 53.3C for 4 min., inducing ca. 2 log CFU/ml inactivation, and serial dilutions were plated on media with or without supplements. Greater numbers of Salmonella (P < 0.05) recovered with the addition of 1g/L ferrous sulfate (FeSO4) to Tryptic Soy agar (TSA) than with the addition of any other supplement, except for 0.5 or 1g/L 3’3’-thiodipropionic acid. Addition of 1g/L sodium pyruvate (CH3COCOONa), or 6g/L yeast extract plus 1g/L CH3COCOONa to TSA supported greater resuscitation than unsupplemented TSA or TSA supplemented with 0.01 or 0.1g/L N-propyl gallate, 10g/L activated charcoal, 0.1g/L KMnO4, or 50mg/L ethoxyquin. Even fewer numbers of Salmonella (P > 0.05) recovered on solidified Fluid Thioglycollate medium or on TSA with addition of the following compounds, ranked in order of performance: 1g/L EDTA > 50g/L sodium thiosulfate (Na2S2O3) > 15g/L NaCl. The remaining supplements supported recovery of equivalent numbers of Salmonella, which was fewer cells than recovered on TSA with 1g/L FeSO4 yet greater populations than recovered on TSA with 50mg/L ethoxyquin. These compounds included 3.5g/L or 6g/L CH3COCOONa, 1 or 5g/L activated charcoal, 0.1 or 0.01g/L FeSO4, 6g/L yeast extract, 1 or 0.5g/L EDTA, 5 or 0.5mg/L ethoxyquin, 0.5 or 5g/L Na2S2O3, 1, 0.1, or 0.01g/L ferric ammonium citrate, as well as unsupplemented plate count agar or TSA. These data suggest that media supplementation with FeSO4, 3’3’-thiodipropionic acid, or CH3COCOONa may aid in recovering sublethally injured Salmonella from LEW.