Amazon registered a trademark in the U.S. for a service described as: "We do the prep. You be the chef." The service will provide customers with "prepared food kits ... ready for cooking and assembly as a meal," according to company's application, which was filed July 6.
"Look, you just have to hope that you don't wake up in the morning and see Amazon has decided to get in your business," Cramer said on "Squawk on the Street."
"It's very significant. I think that Blue Apron will be struggling mightily to keep its business if Prime makes it so you don't have to pay a full boat," he said but added he was rooting for Blue Apron.
Besides Amazon, Blue Apron's rivals include HelloFresh and Plated, which both ship boxes to customer's doorsteps with raw ingredients needed to cook home meals.
Blue Apron, the largest meal-kit provider in the U.S., recently went public but its stock has tumbled. Last week, the shares closed at a new low after an analyst slapped Blue Apron with a $2 price target. The stock at one point Monday was down 10 percent but regained some ground to a drop of 8.2 percent in midmorning trading.
Watch: This is a make or break week for earnings: Jim Cramer