title: Survival and growth of Salmonella enterica serovar enteritidis in membrane-processed liquid egg white with pH, temperature, and storage conditions as controlling factors.
abstract: Processing temperature and pH are known to influence the lethality and cell injury in many microbial interventions. A study was undertaken to determine the effects of variations in solution pH and process temperature on the removal and growth of Salmonella enterica serovar Enteritidis  in liquid egg white (LEW) by microfiltration (MF) membrane process. The effects of various storage conditions on the growth of Salmonella in membrane-separated LEW were evaluated. Pretreated and pH-adjusted (pH 6 to pH 9) LEW was inoculated with a five-strain composite of S. enterica  serovar Enteritidis at ca. 7 log CFU/ml, microfiltered at 25 or 40°C, and stored at 4 or 10°C. Temperature had a greater influence on Salmonella reduction than did pH. The maximum reduction of Salmonella and background microflora in LEW by MF was observed at 40°C  and pH 8 and 9. However, the influence of temperature on permeate flow was less than that of pH. The mean permeate flow increased by 180% at 25°C as the pH decreased from 9 to 6, while flow increased merely by 18% at pH 6 as temperature increased from 25 to 40°C. Salmonella  populations in processed LEW at 4°C storage remained quite stable (0.01 to 0.55 log CFU/ml), irrespective of MF experimental conditions. At 10°C the population was greater, but no major outgrowth was observed. Findings from this study would be advantageous to liquid egg processing industries.
authors.affiliation: U.S. Department of Agriculture, Agricultural Research Service, Eastern Regional Research Center, Wyndmoor, PA 19038, USA. sudarsan.mukhopadhyay@ars.usda.gov
authors.forename: Sudarsan
authors.initials: S
authors.lastname: Mukhopadhyay
authors.forename: Dike
authors.initials: D
authors.lastname: Ukuku
authors.forename: John G
authors.initials: JG
authors.lastname: Phillips
authors.forename: Vijay K
authors.initials: VK
authors.lastname: Juneja
mesh_terms: D015169:Colony Count, Microbial; D003257:Consumer Product Safety; D004529:Egg White / Q000382:microbiology*; D005374:Filtration / Q000379:methods; D005511:Food Handling / Q000379:methods; D005516:Food Microbiology; D061353:Food Storage / Q000379:methods*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D012477:Salmonella enteritidis / Q000254:growth & development*; D013696:Temperature