Effects of holder pasteurization operating parameters on pasteurized raw milk quality

Abstract

A batch pasteurizer could be considered a closed system and it mostly makes use of heat, stirring, or agitation and speed variation as a process parameter for pasteurization. This study investigates if these parameters support the holder pasteurization method using White Fulani cow breed milk samples. The milk samples were pasteurized at 63°C for 30 minutes with slight but insignificant variations in pH values up to 7.55. The stirring speeds used in this study were 30 rpm, 36 rpm, and 42 rpm. The results showed a significant difference in the microbial loads and phytochemical values due to the study treatments. The microbial loads varied between 1.05* 104CFU/ml to 8.25*107 CFU/ml while the phytochemical values were between 0.12 mg/ml to 27.67 mg/ml. The milk samples were poor in phenol and flavonoid but their differences were significant at p≤0.05 after pasteurization. The speed of 30 rpm and 36 rpm did not show a significant difference at p≤0.05 in the fungi counts after the pasteurization. The blade shapes considered were anchor, helical, and vane. These blade shapes used contributed to the holder pasteurization process