The effect of the application of CO2 to extend the cold storage of raw and pasteurized milk on the
content of fat-soluble vitamins of milk was investigated. CO2-treated milk (pH 6.2) was compared
with a control (unacidified) milk. CO2-treated and control raw milk samples were stored at 4 °C
for 4 days. CO2-treated milk was then vacuum degasified, and both control and treated samples
were pasteurized and stored at 4 °C for 7 days. CO2 addition inhibited the growth of microorganisms
in raw milk without affecting the stability of vitamin A (retinol and â-carotene) and vitamin E
(R-tocopherol). Acidity and pH data indicated that subsequent vacuum degasification and
pasteurization on a pilot scale partially removed CO2, making milk acceptable for liquid consumption.
However, the residual CO2 present extended the cold-storage period of pasteurized milk by inhibiting
bacterial survivors without detrimental effects on retinol, â-carotene, and R-tocopherol. Slightly
higher (not statistically significant, p > 0.05) concentrations of retinol, â-carotene, and R-tocopherol
were detected during cold storage in raw and pasteurized CO2-treated milk with respect to the
control milk, which could be related to a certain protective effect of the C
This work was financially supported by the Comisión Interministerial de Ciencia y Tecnología of Spain (Grant ALI96-0406) and by a contract with the S. E. de Carburos Metálicos.
Peer reviewed