Est. 1910. Five point purity checklist. At Mayfield Dairy Farms we strive to achieve the highest quality standards in everything we do - so you can trust. Our products meet the standards of our Five-Point Purity Checklist: Our farmers pledge not to use artificial growth hormones (No significant difference has been shown in milk from cows treated with the artificial growth hormone rbST and non rbST treated cows.). Our milk comes from cows fed a nutritious diet. We reject any milk that contains commonly used antibiotics. Tested for quality at every key step. Cold shipped from dairy to store within hours. Our Farmers Pledge: Not to use artificial growth hormones (No significant difference has been shown in milk from cows treated with the artificial growth hormone rbST and non rbST treated cows.). Comments? 1-800-MAYFIELD.