Antiviral Substances in Raw Bovine Milk Active Against Bovine Rotavirus and Coronavirus.

After experimental contamination of bovine raw and heat-treated milks with bovine rotavirus and coronavirus strains, we observed a strong viral inhibition only with raw milks, from which virus recovery was 5 × 10-4%. Between 30% and 80% of the virus was recovered from the heat-treated milks, depending on the level of inoculation. The antiviral substance is heat-labile (destroyed within 30 min at 100°C), precipitated by ammonium sulfate and filtrable (0.45 μm Millipore membrane). It also has neutralizing activity on tissue culture.