Evaluation of the Use of Sodium Thiocyanate and Sodium Percarbonate in the Activation of the Lactoperoxidase System in the Conservation of Raw Milk without Refrigeration in the Ecuadorian Tropics

摘要

Milk production in Ecuador has enormous economic importance and large-, medium- and small-scale producers all participate in the market. There are multiple climatic regions, and dairy production is present in every one of them. High ambient temperatures in the Ecuadorian tropics represent a key challenge to the conservation of milk in the custody of smallholders. The objective of the present study was to evaluate the efficiency of the application of a chemical activator of the Lactoperoxidase System (LP-s) in the conservation of raw milk, at room temperature, in the Ecuadorian tropics. In the present study, sodium thiocyanate—0.36 g·L-1 of milk—and sodium percarbonate—1.36 g·L-1 of milk—as an activator of LP-s were used and the pH and microbiological characteristics (total coliforms, Staphylococcus aureus, total aerobes, molds and yeasts) of the milk at different storage times (0, 4 and 8 hours). The results obtained in the present study showed a significant difference between the two groups under study at 8 hours of storage at room temperature in all parameters (except yeasts where there was no growth in the two treatments), being relevant the significant decrease of the bacterial content. Thus the present study shows that the use of sodium thiocyanate and sodium percarbonate in the above described concentrations could be modulating the activation of LP-s that provides an efficient alternative for the conservation of the raw milk without refrigeration, improving the income for losses of the product and obtaining a raw material of good quality for sale or for further processing, mainly for small producers who do not have the economic resources to have refrigeration means for their product and who must transport their milk for considerably longer distances until they arrive at the collection centers or the processing plants for sale, thus showing that the method used in the present study is not only effective but also has a relatively low cost and easy application.