Revised model for aerobic growth of Shigella flexneri to extend the validity of predictions at temperatures between 10 and 19 degrees C

• Published in: International journal of food microbiology 1998-05, Vol.41 (1), p.9-19
• Main Authors: Zaika, L.L, Phillips, J.G, Fanelli, J.S, Scullen, O.J
• Format: Article
• Language: English
• Subjects: aerobic conditions; beef broth; brain heart infusion broth; canned fish; chicken broth; Colony Count, Microbial; culture media; equations; food contamination; Food Microbiology; Food Preservation; foods; Forecasting; growth; growth models; Hydrogen-Ion Concentration; infant foods; Kinetics; Least-Squares Analysis; Linear Models; meat products; microbial contamination; Models, Biological; salmon; Shigella flexneri; Shigella flexneri - growth & development; sodium chloride; Sodium Chloride - metabolism; sodium nitrite; Sodium Nitrite - metabolism; Temperature; UHT milk
• ISSN: 0168-1605; 1879-3460
• DOI: 10.1016/S0168-1605(98)00037-3

Although Shigella is a major foodborne pathogen, its growth in foods has received little attention. Growth of S. flexneri 5348 inoculated into commercially available sterile foods (canned broths, meat, fish, UHT 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 were fitted by the Gompertz equation. Observed growth kinetics values and values calculated using a previously developed surface model compared favorably for growth at 19 to 37 degrees C, but not at < 19 degrees C. To refine the model, additional data were collected for growth at 10 to 19 degrees C. A total of 844 tests in BHI broth, representing 197 variable combinations of temperature (10-37 degrees C), pH (5.0-7.5), NaCl (0.5-5.0%) and NaNO2 (0-1000 ppm) was used for the revised model. The revised model, developed in BHI, gave significantly better agreement of calculated growth kinetics values with those observed in 10 to 19 degrees C.