Dairy producer The A2 Milk Company is dramatically expanding its business in the United States, rolling out its products across the north-east of the country to give it a presence in 5,000 stores nationwide.

The company says sales levels in its initial markets around California now support a swing into the rich north-eastern states, reaching a potential 60 million milk drinkers from New York, through Connecticut, to Vermont and Maine, or some 20 per cent of the US milk market by volume.

“Sales velocities are now achieving sustainable levels in California, the South East region and select natural retail chains, which supports the expansion into an additional region,” the company said in a statement on Wednesday.

A2 Milk USA chief executive Blake Waltrip said the company hit its sales targets while national brand awareness was still relatively low and he expects the next stage could double its US business.

“Our strategy has been: we establish a stable and consistent market presence that is strong and sustainable and then we build on that to expand into the next region. And, that’s exactly what we’ve done here,” Mr Waltrip said.

A2 milk, which listed on the ASX in 2015 at 56.5 cents a share, bases its products on a number of patented processes including genetic testing to identify A1 and A2 proteins in cow milk.

A2 Milk can license dairy farmers that prove their cows produce only the A2 protein in their milk, and not the A1 protein, which the company associates with digestive discomfort.

Mr Waltrip said 75 million US consumers identify themselves as milk intolerant.

“The incredible focus of consumers on health and wellness here is nothing short of amazing,” he said.

A2 Milk on Wednesday said it had been accepted into major retailers and, starting in January, will lift its US presence from 3,600 stores to 5,000 including major US retailers, such as Shoprite, Safeway and H-Mart.

The news boosted A2 Milk Company’s shares which were up 18 cents, or 2.4 per cent, at $7.60,at 1143 AEDT.