Journal of Food Processing & Technology

The effect of enrichment broth and temperature on the recovery of Salmonella

21^st Euro-Global Summit on Food and Beverages

March 08-10, 2018 | Berlin, Germany

Douglas E Cosby

USDA, USA

Scientific Tracks Abstracts: J Food Process Technol

Abstract:

Statement of the Problem: No single enrichment broth or temperature is used consistently throughout the research, regulatory or industry laboratories for the detection of Salmonella. This lack of a single methodology leads to confusion and possible bias both for and against Salmonella serotypes. The objective was to evaluate four selective enrichment broths [selenite cystine (SC), tetrathionate Hajna (TT), GN broth (GN) and Rappaport-Vassialiadis (RV)] at two temperatures (37�?? and 42�??) to determine the best for growth of four Salmonella serovars. Methodology: Four Salmonella serovars [Enteritidis (SE), Heidelberg (SH), Kentucky (SK) and Typhimurium (ST)] were inoculated individually (101 cfu) into duplicate tubes containing 10 mL of each of four enrichment broths at each temperature. After overnight enrichment, serial dilutions were plated onto brilliant green sulfa (BGS) agar plates for enumeration. Counts were made and recorded after 24 h incubation. Three replicates were conducted. Conclusion & Significance: All four enrichment broths were significantly (P<0.05) more effective for recovery at 37�?? than at 42�??. When incubated at 37�??, recovery in SC was log10 4.4, 7.7, 7.6 and 7.5 for SE, SH, SK and ST, respectively; recovery in GN was log10 8.2, 8.4, 8.5 and 8.4 for SE, SH, SK and ST, respectively; recovery in TT was log10 6.9, 7.6, 8.1, and 7.3 for SE, SH, SK and ST, respectively; and recovery in RV was log10 8.1, 8.2, 8.2 and 7.9 for SE, SH, SK and ST respectively. At 37�??, significant differences were observed between TT/GN; TT/RV; SC/GN; and SC/RV and none observed between SC/TT or GN/RV. At 42�??, no significant difference was observed between three broths (SC, TT and RV) when Salmonella was recovered. Recovery of Salmonella strains can unintentionally be biased by on the incubation temperature or the enrichment broth selected simply because of laboratory preference or regulatory protocol. Recent publications 1. Cosby D E, N A Cox and M E Berrang (2016) Ecometric evaluation of Salmonella selective enrichment broths to suppress background microflora. Poultry Sci. 95(E-Suppl 1):161-162. 2. Cosby D E, N A Cox and M E Berrang (2016) Growth of Salmonella in four enrichment broths at 37 or 42�??. Poultry Sci. 95(E-Suppl 1):161. 3. Cox N A, K E Richardson, D E Cosby, M E Berrang, N Holcombe and C Weller (2017) The effect of environmental poultry samples on the pH of typical pre-enrichment and enrichment media following incubation. J. Appl. Poult. Res., 27(1):112-115. 4. Richardson K E, N A Cox, D E Cosby, M E Berrang and L DeRome (2017) Acid tolerance of dry-stressed Salmonella. Poult. Sci. 96(E-Suppl. 1):312. 5. Richardson K E, N A Cox, D E Cosby and M E Berrang (2017) Impact of desiccation and heat exposure stress on Salmonella tolerance to acidic conditions. J. Environ. Sci. and Health, Part B., 53(2):141-144.

Biography :

Douglas E Cosby received his PhD in Food Science from University of Georgia (2012). His expertise is in the research and development of intervention strategies to reduce or eliminate Salmonella, Campylobacter, Listeria, and Clostridium species from poultry and poultry products on farm and in the processing plant. He has worked at the US Department of Agriculture, Agriculture Research Service for the past 30 years and serves an Adjunct Assistant Graduate Professor at the University of Georgia, Department of Food Science and Technology. His current research is aimed at preventing and/or reducing enteropathogenic salmonella and campylobacter on poultry and poultry products by preventing the colonization of poultry through the use of biosecurity and/or feed additives in live poultry and through the mechanical removal of enteropathogenic bacteria and/or the use of gras chemicals to reduce or eliminate the bacteria.
Email:douglas.cosby@ars.usda.gov