Dankner notes that "not all Mexican milk is pasteurized, and there is a belief that cheese tastes better if un-pasteurized milk products are used to produce it." (He doesn't dispute that un-pasteurized milk products may be tastier.)
"No toda la leche mexicana se pasteuriza", observa Dankner, "y existe la creencia de que el queso sabe mejor si se hace con leche no pasteurizada."