PLATELET-ACTIVATING-FACTOR (PAF) ANTAGONISTS IN FOODS - A STUDY OF LIPIDS WITH PAF OR ANTI-PAF-LIKE ACTIVITY IN COWS MILK AND YOGURT

Yogurt, a food with indisputable nutritional value, is also used for t herapeutic purposes. Milk derivatives are blamed for some pathological effects of yogurt noted in selected subjects such as sensitive newbor ns or infants, In this study, we investigated the probable existence o f platelet-activating factor (PAF) and lipids inhibiting PAF action in raw and incubated milk and yogurt. Detection of these substances may explain the controversial properties of these milk products. The in vi tro biological study of lipids in washed platelets showed little produ ction of PAF in incubated milk (0.3-0.8 ng/100 mL sample) although the concentration of PAF in milk fat remained constant during the majorit y of the incubation time. Yogurt lipids of intermediate polarity prese nted stronger inhibitory activity against PAF than lipids corresponded to raw or incubated milk. Our data demonstrated that Streptococcus th ermophilus and Lactobacillus bulgaricus biosynthesize important quanti ties of PAF inhibitors, whereas random contamination of milk leads to the production of small amounts of PAF and PAF inhibitors.