Growth of Pseudomonas fluorescens and Candida sake in homogenized mushrooms under modified atmosphere

• Published in: Journal of food engineering 2002-09, Vol.54 (2), p.125-131
• Main Authors: Masson, Yannick, Ainsworth, Paul, Fuller, David, Bozkurt, Hüseyin, İbanoǧlu, Şenol
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Food industries; Fruit and vegetable industries; Fundamental and applied biological sciences. Psychology; Growth kinetics; Growth parameters; Mathematical models; Microorganisms; Modeling; Modified atmosphere; Mushrooms; Packaging; pH effects; Regression analysis; Spoilage microorganism; Thermal effects
• ISSN: 0260-8774; 1873-5770
• DOI: 10.1016/S0260-8774(01)00193-5

Pseudomonas fluorescens and Candida sake were inoculated into mushrooms and stored under different gaseous atmospheres: air, CO 2:N 2:O 2 (25:74:1%) and CO 2:N 2:O 2 (50:49:1%). The growth of both microorganisms was measured during 18 days of storage at 5 and 10 °C. The percentages of O 2 and CO 2 inside the package and the pH of mushrooms were monitored during the storage. The maximum specific growth rate constant ( μ m), lag time ( λ) and maximum population density ( A) were evaluated from the modified Gompertz model using non-linear regression. The percentage of O 2 in the samples stored in air decreased progressively during an 18-day storage while the percentage of CO 2 increased. The pH of the samples stored under CO 2 decreased whereas the pH of samples stored in air at 10 °C increased during the first 4 days followed by a decrease for the rest of the storage. The lag time increased with an increase in the percentage of CO 2 in the atmosphere. The results suggest that the modified Gompertz model can be used successfully to describe the growth of both C. sake and P. fluorescens in mushrooms. Low CO 2/high storage temperature combinations were found to favor the growth for both microorganisms.