Effect of microbiological characteristics of raw milk on the quality of whole milk powder

Abstract

The relationship between microbiological characteristics of raw milk and the quality of high-heat whole powder made from it was investigated. To this end, 16 lots of milk standardized for fat and non-fat solids were used. Powder average levels of mesophiles and psychrotrophs were 7.8 × 101 and 4.0 × 101 CFU/g, respectively, and these values correlated positively (P < 0.05) with the corresponding raw milk counts (8.1 × 106 and 1.8 × 107 CFU/g, respectively). A significant positive correlation (P < 0.05) was also observed between raw milk psychrotroph counts and titratable acidity of milk powder (range: 0.15-0.19 as % lactic acid). Samples of powder produced from raw milk with higher psychrotroph levels were found to have higher insolubility indexes, yet this relationship was not statistically significant. The importance of milk hygienic control as a basic instrument to warrant commercial milk powder quality is discussed.