Qualidade do leite de cabra in natura e do produto pasteurizado armazenados por diferentes períodos

Abstract

QUALITY OF IN NATURA GOAT MILK AND PASTEURIZED PRODUCT STORED FOR DIFFERENT PERIODS. Different periods (0, 3 and 6 days) and 2 temperatures (4 °C and 10 °C) of raw goat’s milk storage and its impact on pasteurized product quality and shelf life were evaluated. In the described periods, slow pasteurization (65 °C/30 min) was carried out and the pasteurized product was stored at 10 °C for 6 days. Raw milk samples were characterized after milk handling and after 3 and 6 days of storage. Pasteurized milk was evaluated immediately after heat treatment and after 3 and 6 days of storage at 10 °C. The counting of mesophiles, total, lipolytic and proteolytic psichotrophic bacteria, total and fecal coliforms, acidity, fat and free fatty acid (FFA) contents were determined. The microorganisms’ populations had a higher growth at 10 °C than 4 °C. Acidity remained in acceptable levels during storage at 4 °C for 6 days, but not at 10 °C. There was a significant decrease (p < 0.05) in raw milk fat content during storage in both temperatures and a gradual increase of free fatty acids (FFA). Pasteurization was efficient in the reduction of bacteria populations and the lipolytic and proteolytic psichrotrophic microorganisms were non-detectable after heat treatment. However, alterations during raw milk storage affected physical-chemical characteristics of pasteurized milk. During storage, values of pasteurized milk acidity and fat content remained stable, while the amount of FFA increased significantly. It was concluded that raw goat’s milk can be stored for up to 3 days at 4 °C before heat treatment. This condition promotes 6 days of shelf-life after pasteurization. In addition, 10 °C is not a suitable