Death Rate of the Indigenous Mixed Spore Flora in Skimmilk and Skimmilk Concentrates

By means of strictly regulated treatment conditions to heat skimmilk and skimmilk concentrates the conditions for the destruction of the natural mesophilic and thermophilic mixed spore flora in the products were found. It could be shown that the heat resistance of mesophilic spores increased as the concentration of the product was raised up to 30% total solids (TS) and remained fairly constant in media of higher concentration. The heat resistance of thermophilic spores remained constant up to a product concentration of about 30% TS and decreased considerably in more highly concentrated products. This suggests that the changes in the product produced by concentration stabilized the mesophilic mixed spore flora and destabilized the thermophilic spore flora.