Efecto de la adición de mucílago de Opuntia ficus-indica y Opuntia atropes a la leche cruda sobre bacterias mesófilas aerobias y coliformes totales

Abstract

Raw milk is one of the most important food for human consumption, particularly for small dairy farms who produce milk either self-consumption or to sell it to local artisanal cheese makers; due to the elevate risk of contamination by pathogenic bacteria, it is important to offer alternatives to enhance microbiological quality of raw milk. Thus, the objective of this study was to evaluate the addition of liquid mucilage and dried mucilage from Opuntia ficus-indica and Opuntia atropes to the raw milk on the growth of mesophilic aerobic bacteria and total coliforms. Raw milk samples from Holstein cows supplied by a smallholder was added with liquid mucilage or dried mucilage from O. ficus-indica or O. atropes at concentrations of 0.5, 1.0 and 2.0%. Samples were measured for mesophilic aerobic bacteria and total coliforms and results were analyzed by the fixed effects model and means comparisons. In general, counts of mesophilic aerobic bacteria and total coliforms were significant reduced (P<0.05) when both mucilages were added at 0.5%, independently of the physical form (dried or liquid) added to the raw milk. Lower counts of mesophilic aerobic bacteria (P<0.05) were observed when dried mucilage from O. ficus indica (log10 2.6 CFU mL-1) and O. atropes (log10 2.7 CFU mL-1) were added at 0.5%, respectively. Control raw milk with no added mucilage had log10 3.6 CFU mL-1. The best response for total coliforms was observed when dried mucilage was added at 1% from O. ficus-indica (log10 3.0 CFU mL-1) and liquid mucilage at 1% from O. atropes (log10 2.7 CFU mL1). Dried mucilage or liquid mucilage from O. ficus-indica and O. atropes reduced the microbial content of raw milk.