REVISED MODEL FOR AEROBIC GROWTH OF SHIGELLA-FLEXNERI TO EXTEND THE VALIDITY OF PREDICTIONS AT TEMPERATURES BETWEEN 10-DEGREES-C AND 19-DEGREES-C

Although Shigella is a major foodborne pathogen, its growth in foods h as received little attention. Growth of S. flexneri 5348 inoculated in to commercially available sterile foods (canned broths, meat, fish, UH T milk, baby foods) was studied at 10 to 37 degrees C. S. flexneri was enumerated by surface-plating on Tryptic Soy Agar and growth curves w ere fitted by means of the Gompertz equation. Observed growth kinetics values and values calculated using a previously developed response su rface model compared favorably for growth at 19 to 37 degrees C, but n ot at < 19 degrees C, To refine the model, additional data were collec ted for growth at 10 to 19 degrees C. A total of 844 tests in BHI brot h, representing 197 variable combinations of temperature (10-37 degree s C), pH (5.0-7.5), NaCl (0.5-5.0%) and NaNO2, (0-1000 ppm) was used f or the revised model. The revised model, developed in BHI, gave signif icantly better agreement of calculated growth kinetics values with tho se observed in foods at 10 to 19 degrees C. (C) 1998 Elsevier Science B.V.