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Chilling invokes different morphologies in two Salmonella enteritidis PT4 strains
L E Phillips1, T J Humphrey, H M Lappin-Scott
1PHLS Food Microbiology Research Unit, Hatherly Laboratories, Exeter, UK. lisa.phillips@oxdgo.sprint.com
Journal of Applied Microbiology
|July 23, 1998
Summary
Chilling food causes cell elongation and injury in Salmonella enteritidis PT4 strain E, but not strain I. This highlights chilling
Area of Science:
- Food Science
- Microbiology
- Bacteriology
Background:
- Reduced chemical preservatives in food processing leads to increased use of refrigerated (chilled) products.
- The impact of chilling on Salmonella enteritidis PT4 isolates is not well understood.
Purpose of the Study:
- To investigate the effects of chilling on two Salmonella enteritidis PT4 isolates (E and I).
- To compare the responses of isolates with differing tolerance to heat, acidification, surface survival, and animal model behavior.
Main Methods:
- Comparative analysis of two Salmonella enteritidis PT4 isolates (E and I) under chilling conditions.
- Assessment of cell morphology (elongation, size), sublethal injury, and recovery of resistance.
- Hypothesizing mechanisms for observed cell elongation, including cell division and outer membrane changes.
Main Results:
- Chilling induced significant cell elongation and approximately 90% sublethal injury in isolate E.
- Isolate I showed neither substantial cell elongation nor significant injury under chilling.
- Recovery of desoxycholate resistance in isolate E correlated with a return to normal cell size.
Conclusions:
- Chilling profoundly affects Salmonella enteritidis PT4 isolate E, causing cell elongation and injury, unlike isolate I.
- Incomplete cell division is a likely cause of chilling-induced cell elongation in Salmonella.
- Cell elongation in the heat- and acid-tolerant strain E may be linked to its pathogenicity.