Removal of Bacteria from Food Raw Materials by Electrophoresis

SUMMARY To determine proper conditions for removal of bacteria from food by electrophoresis, a microscopic study was made of the influences of electrical double layer, intensity of electrical field, electric density gradient, pH of the buffer solution, ionic strength of buffer solution, stage of growth of bacteria, and anion surface‐active agent upon the electropboretie mobility of some species of bacteria. The effect of the electrical double layer between the electrophoretic cell wall and bacterial solution was determined. The observed mobility of the bacteria was smaller at the upper and bottom sides of the cell than the true mobility, and was larger at the center of the cell. The migration velocity (μ/sec) of the bacterial cell is proportional to the intensity of the electric field. The mobility of the bacteria increased at random with increased voltage. The mobility of the bacteria varied directly with the pH value of the buffer solution in which they were suspended. With increase of ionic strength of buffer solution, the mobility of bacterial cells decreased for each species of bacteria used. The mobilities of some sporeforming bacteria varied at various stages of the growth period: mobility increased rapidly after germination and during the logarithmic phase, decreased for vegetative cells in the stationary phase, and decreased much more as the cells entered the sporeforming stage. Bacterial mobility was increased substantially by sodium tetradecyl sulfate.