Effect of six organic acids on staphylococcal growth and enterotoxin production.
Four Staphylococcus aureus strains were incubated at 37 degrees C for 24 h in broth progressively acidified with lactic, citric, ascorbic, acetic, pyruvic and propionic acids, and their survival rate and enterotoxin producing ability was studied. Acids were chosen based on their frequent use by the food industry. Periodically, samples were withdrawn to determine counts, pH and the presence of enterotoxins A, B, C, and D. For a given acid, the effect on growth and enterotoxin synthesis was different. The most inhibitory acid for the growth of strains FRI-100 and FRI-472 was pyruvic acid, for strain FRI-137 was lactic acid, all six acids were equally effective on strain S6. Lactic acid was very inhibitory to enterotoxin synthesis, but the effect on this parameter of acetic and citric acids was almost nil. Enterotoxins were seen to be inactivated at acid pH values; enterotoxin B was the most resistant to inactivation.
Domenech
A
A
Departamento de Patologia Animal I, Facultad de Veterinaria, Universidad Complutense, Madrid, Spain.
Hernandez
F J
FJ
Orden
J A
JA
Goyache
J
J
Lopez
B
B
Suarez
G
G
Gomez-Lucia
E
E
D000085:Acetates / Q000494:pharmacology; D019342:Acetic Acid; D001205:Ascorbic Acid / Q000494:pharmacology; D002264:Carboxylic Acids / Q000494:pharmacology*; D002951:Citrates / Q000494:pharmacology; D019343:Citric Acid; D004768:Enterotoxins / Q000037:antagonists & inhibitors / Q000096:biosynthesis*; D004797:Enzyme-Linked Immunosorbent Assay; D005516:Food Microbiology; D006863:Hydrogen-Ion Concentration; D007773:Lactates / Q000494:pharmacology; D019344:Lactic Acid; D011422:Propionates / Q000494:pharmacology; D011773:Pyruvates / Q000494:pharmacology; D019289:Pyruvic Acid; D013211:Staphylococcus aureus / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism
D000085:Acetates; D002264:Carboxylic Acids; D002951:Citrates; D004768:Enterotoxins; D007773:Lactates; D011422:Propionates; D011773:Pyruvates; D019343:Citric Acid; D019344:Lactic Acid; D019289:Pyruvic Acid; C029658:propionic acid; D001205:Ascorbic Acid; D019342:Acetic Acid