Model for the survival of Staphylococcus aureus in nongrowth environments.
A model was developed to estimate the survival times of Staphylococcus aureus in nongrowth environments. A four strain mixture of S. aureus was inoculated into BHI broth that had a lactate buffer with various combinations of pH (3-7) and lactate (0-1%), NaCl (0.5-20%) and NaNO2 (0-200 ppm) and stored at different temperatures (4-42 degrees C). At appropriate times the survivors were enumerated by sampling and spreading on TSA plates. The survival curves were modeled with two forms of a logistic equation and the D values were determined. Polynomial regression equations were then calculated to predict the effect of the environmental factors on the D values. Survival times were increased with higher pH values, lower temperatures, and lower nitrite and lactate concentrations. Added salt increased survival times until the salt concentrations exceeded that of most foods.
Whiting
R C
RC
Microbial Food Safety Research Unit, U.S. Department of Agriculture, Wyndmoor, PA 19038, USA.
Sackitey
S
S
Calderone
S
S
Morely
K
K
Phillips
J G
JG
D005516:Food Microbiology; D006863:Hydrogen-Ion Concentration; D007773:Lactates / Q000494:pharmacology*; D008954:Models, Biological; D012965:Sodium Chloride / Q000494:pharmacology*; D012977:Sodium Nitrite / Q000494:pharmacology*; D013211:Staphylococcus aureus / Q000187:drug effects / Q000254:growth & development*; D013696:Temperature; D013997:Time Factors
D007773:Lactates; D012965:Sodium Chloride; D012977:Sodium Nitrite