What is rBST?

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Cows grazing in a field

Cows naturally create bovine somatotropin (BST)—it’s a hormone produced in the pituitary gland. The “r” in front of BST stands for recombinant which means it’s genetically modified using recombinant DNA technology.* That’s something created in a lab, not in a cow. You may also have seen it labeled rBGH or recombinant bovine growth hormone.

In 1993, the FDA approved the use of Monsanto’s injectable rBST formula called Posilac. Why would a cow need rBST/rBGH? Simply put, it is used to increase a cow’s ability to produce milk.

Farm-Fresh Dairy DepartmentrBST Free-Products at Sprouts

Although the dairy industry has been allowed to use rBST in their cows for decades, we believe GMO and rBST-free milk is best. rBST free milk can be used to make a variety of products like rBST free yogurt, ice cream or cheese. We’ve got a fantastic selection of delicious cheeses—next time you’re in the store, swing by our deli section and check out the 21 varieties of bulk-cut cheeses (hand cut in-store) that are rBST-free!


*Recombinant DNA technology is the joining together of DNA molecules from two different species that are inserted into a host organism to produce new genetic combinations that are of value to science, medicine, agriculture and industry.