Short-chain organic acids at ph 5.0 kill Escherichia coli and Salmonella spp. without causing membrane perturbation.
When strains of Escherichia coli K12 and Salmonella spp. were incubated with 0.5-0.7 mol/l formic or propionic acid at pH 5.0, propionic acid was more active than formic acid. It killed 90% of the cell population within 60 min compared with over 3 h for formic acid. Cell death was not associated with a reduction in culture turbidity or a loss of membrane integrity since morphologically normal membranes were observed by electron microscopy and only a small proportion of the cytoplasmic enzyme beta-galactosidase leaked into the supernatant fluid of acid-treated E. coli K12 cultures.
Cherrington
C A
CA
Department of Veterinary Medicine, University of Bristol, Langford, Avon, UK.
Hinton
M
M
Pearson
G R
GR
Chopra
I
I
D002462:Cell Membrane / Q000187:drug effects / Q000201:enzymology; D004926:Escherichia coli / Q000187:drug effects* / Q000201:enzymology / Q000648:ultrastructure; D005561:Formates / Q000494:pharmacology*; D006863:Hydrogen-Ion Concentration; D008854:Microscopy, Electron; D011422:Propionates / Q000494:pharmacology*; D012475:Salmonella / Q000187:drug effects*; D001616:beta-Galactosidase / Q000032:analysis
D005561:Formates; D011422:Propionates; C030544:formic acid; D001616:beta-Galactosidase; C029658:propionic acid