GROWTH MODELING OF THE PREDOMINANT MICROBIAL GROUPS IN HAMBURGERS IN RELATION TO THE MODULATION OF ATMOSPHERE COMPOSITION, STORAGE-TEMPERATURE, AND DIAMETER OF MEAT PARTICLE

The gas composition, storage temperature, and diameter of meat particles in modified-atmosphere-packaged hamburgers were modulated according to a Central Composite Design with the aim of assessing the effects of these variables and their interaction on the predominant spoilage microbial groups, gas atmosphere and colour modifications. The parameters of the growth curves, analyzed according to the Gompertz equation, as well as the rate of gas composition and colour modification, were analyzed in order to obtain polynomial equations. The model obtained emphasized the role attributable to a structural variable such as the diameter of particles and to its interaction with atmosphere composition and temperature. Brochothrix thermosphacta was the organism endowed with the highest growth potential in the three-dimensional space defined by the range of the variables taken into consideration. The iso-response surfaces obtained and a comparison of the responses of the various groups permit the identification of the conditions able to reduce the growth of potentially hazardous micro-organisms.