Physico-chemical and microbiological properties of high pressure treated cow and goat milk

Tan, Sok Fern (2019) Physico-chemical and microbiological properties of high pressure treated cow and goat milk. [Project Paper] (Submitted)

Text lp FK 2019 8.pdf Download (47MB)

Abstract

High pressure processing (HPP) on cow and goat milk was conducted at 450 MPa for 7 min, 600 MPa for 5 min and 600 MPa for 7 min to investigate the effects on physic-chemical and microbiological properties in comparison to high-temperature-short-time (HTST) pasteurization at 72⁰C for 15 sec. Both HPP and pasteurization effectively reduced the bacterial and spore populations to beyond the permissible limit, with highest total plate count reduction 99.99% by HPP treatment at 600 MPa and 5 min. All treatments caused no significant changes to most of the physic-chemical properties such as titratable acidity, specific gravity, total protein, total fat, total solid and solid-non-fat. However, pH of pasteurized cow milk has decreased significantly (from 6.59 to 6.52) while both pasteurized and HPP treated goat milk have significant increased pH (from 6.34 to 6.38-6.42). During storage at 8⁰C, HPP treated cow and goat milk both achieved microbial shelf life of 22 days with no increased in Bacillus cereus, maesophilic aerobic spores, coliform, yeast and mould but slight increase in psychotropic bacteria and total plate count. However, pasteurised goat milk was spoilt at the end of the storage as both psychotropic bacteria (9.0 x 10⁸CFU/ml) and total plate count (3.5 x 10⁸CFU/ml) have exceeded the permissible limits. HPP treated cow milk exhibited higher physic-chemical stability than goat milk which is most evident in the significant increment (average 0.04%) in goat milk’s titratable acidity while no significant changes observed in cow milk.

Item Type:	Project Paper
Faculty:	Faculty of Engineering
Depositing User:	Ms. AZLINA ZAINAL ABIDIN
Date Deposited:	20 Oct 2023 07:54
Last Modified:	20 Oct 2023 07:54
URI:	http://psaspb.upm.edu.my/id/eprint/1582

Actions (login required)

View Item