The aim of this study was to make a new teat dip formula containing lactic acid and evaluate its stability and antibacterial activity by physico-chemical and microbiological tests. After selecting the concentrations of the thickener xanthan gum (0.67%) and lactic acid (6.3%), a teat dip solution was composed, which contains teat skin saving components: glycerol, sorbitol, oat and calendula extracts. According to the recipe, a teat dip solution of orange colour, homogeneous appearance, and a specific lactic acid smell was composed, the viscosity of which was 930–940 mPa*s., pH 2.7. Product physical, chemical properties and stability for 24 months were confirmed by realtime and accelerated stability studies. The teat dip solution remains homogenous, orange colour with a typical lactic acid smell, and did not become cloudy or flaky after 24 months following production. Viscosity reduction was determined after 6 months 33 mPa*s, i.e. it was 3.4%, while after 24 months, it was 12.7%. The measured pH value remains stable between 2.6 and 2.8 (P > 0.05). An antimicrobial

study was performed according to EN 1656 by 80%, 50% and 10% concentrations with reference Staphylococcus aureus, Streptococcus uberis and Escherichia coli strains. The teat dip solution showed bactericidal efficiency (log R > 5) against S. uberis and E. coli reference strains. An antimicrobial effect to S. aureus was insufficient and the product was not effective against this bacteria. Teat dip at 10% did not show an antimicrobial effect to all tested strains. According to these data, the new model teat dip solution containing lactic acid, teat skin saving substance and thickener xanthan gum retains unchanged physical parameters and shows bactericidal activity against the reference E. coli and S. uberis strains.