The effect of physical and microbiological factors on food container leakage

摘要

The effect of physical and microbiological factors on food container leakage was investigated in a container leakage model system (CLMS). The leakage ofAcineto‐bacter calcoaceticus, Staphylococcus sp., Pseudomonassp.,Bacillussp., a coryneform,Staph. aureus, and two biotest organisms (Enterobacter cloacaeNC1B 8151 andEnt. aerogenesMB31) was studied. The rate of bacterial leakage (log10cells/channel/s) was greater in the presence of a partial vacuum of 51–305 mm Hg than at atmospheric pressure. Fluid flow (ml) through leakage channels was increased by the application of vacuum. Leakage varied with vacuum, bacterial morphology, cell concentration, leakage channel size (0.78–120 μm2) and channel shape (straight or convoluted). The number of leaked cells was not proportional to vacuum or channel size. The effect of channel shape varied with bacterial species. Increased container medium viscosity decreased bacterial leakage. Fluid flow through leakage channels was generally reduced by the most viscous solution. Cells from biofilms and mono‐layers ofAc. calcoaceticusorStaph. aureusattached to nylon (Hyfax) or stainless steel surfaces underwent leakage. Mixed bacterial populations had characteristic leakage rates against vacuum different from the leakage pattern of individual species in the population. The composition of the leaked population was different from the original inoculum. The results indicated that container leakage is a complex process involving a range of interdependent