FSSAI said that these claims do not conform with the Food Safety and Standards Act, 2006.

"It has come to the notice of FSSAI that several Food Business operators are selling/marketing Milk and Milk products such as Ghee, Butter, Curd, etc in the name of A1 and A1 under FSSAI License Number and/or Registration Certificate Number," the notice read.

The Food Safety and Standards Authority of India (FSSAI), in its latest order, said that it had examined the issues and found that A1 and A2 differentiation is linked to the structure of beta-casein protein in milk.

A1 and A2 milk differ in their beta-casein protein composition, which differs based on cow breed.

But this differentiation is not recognised by the current regulations of the FSSAI.

"FBOs are instructed to remove such claims from their products," the regulator said while referring to food business operators. E-commerce platforms have been told to remove these claims from products and websites with immediate effect.

FSSAI has given 6-months time to the companies to exhaust the pre-printed labels, with no further extensions to be granted.

The president of the Indian Diary Association (IDA), RS Sodhi, said that this landmark notification by the FSSAI is to "protect consumers from unscientific claims by food and dairy companies".

WHAT DOES A1, A2 MEAN?

Understandably, many milk-based products in the market are sold with A1 and A1 labels, making consumers wonder as to what it means to have an A1 or A2 milk product.

A1 and A2 milk differ in their beta-casein protein composition, which varies based on cow breed.

According to Healthline, Casein is the biggest group of proteins in milk, which makes up of 80 per cent of the total protein content.

Milk contains several types of casein and of these beta-casein is the second most prevalent, existing in at least 13 different forms.

The two most prevalent forms are:

• A1 beta-casein: This form is mostly found in the cow breeds that originate from northern Europe, including Holstein, Friesian, Ayrshire and British Shorthorn.

• A2 beta-casein: Milk high in this form of beta-casein is primarily found in cow breeds that originate in southern France and Channel Islands, including Guernsey, Jersey, Charolais and Limousin cows.

While regular milk has both A1 and A1 beta-casein, A2 milk contains only the A2 variant. Notably, some studies have suggested that A1 beta-casein might be harmful while A2 variant is a safer choice.

What's Wrong With A1?

According to Healthline, an opioid peptide -- Beta-casomorphin-7 (BCM-7) -- is released during the digestion of the A1 beta-casein.

Some studies have revealed that BCM-7 might be linked to type-1 diabetes, heart disease, infant death, autism and digestive issues.

However, reports said that it remains unclear as to till what extent does BCM-7 is absorbed intact into one's blood.

One of the studies found high levels of BCM-7 in infants' blood, who temporarily stopped breathing during sleep. A condition, known as sleep apnea, which is connected to an increased risk of sudden infant death syndrome (SIDS).

One another factor is lactose content. While the amount of lactose in A1 and A2 milk is the same, some people feel that A2 causes less bloating in comparison to A1.

Scientists, as per Healthline, suggested that some of the milk proteins might be the reason behind some people's intolerance towards milk.

One of the studies conducted among Chinese adults found that A2 milk caused them significantly less discomfort after meals. Studies based on both animals and humans have suggested that A1 beta-casein might increase inflammation in the digestive system.