Surface contamination in the form of discrete colony-forming units is the main source of bacteria associated with meat spoilage. The fate of these bacteria is determined by the microenvironment at the meat-atmosphere interface, where the constraints determine the nature of a developing microflora. Nutrients, water availability and nutrient diffusion are prominent factors influencing microbial activity. While surface growth is most commonly recognized through enumeration studies based on removal of microorganisms, the less-studied phenomenon of movement of bacteria may be of considerable significance. In model systems, Serratia marcescens moves rapidly in intact meat as well as in compacted comminuted meat. The invasion process may depend on specific enzymes rather than the general class of collagenases. Need for more knowledge about factors that control surface microenvironment of meat is apparent.