Almonds surely don’t lactate—but keeping various milk products straight may not be a breeze.

HP Hood LLC is voluntarily recalling more than 145,000 half-gallon cartons of its Vanilla Almond Breeze almond milk after a batch was tainted with cow’s milk. “Employee error” was to blame for spoiling the non-dairy drink, according to the company, which announced the recall late last week.

The udder mix-up spilled the bitter truth about the almond milk’s production: it’s being processed in the same facility as cow’s milk, its legen-dairy rival. The revelation may leave a sour taste for some as regulators and lawmakers are currently grappling with the definition of “milk.” The dairy industry, of course, is continuing with its long-standing argument that companies selling non-dairy beverages are profiting off moo-juice’s good name.

Just last month, Food and Drug Administration Commissioner Scott Gottlieb noted that current agency standards indeed identify milk products specifically as those derived from lactating animals—which would exclude non-mammary liquids wrung from nuts, soy beans, rice, coconuts etc. from being called “milk.” Gottlieb said the agency would review the situation and soon issue a new regulatory guidance on how beverage makers should use the term in product marketing and labeling.

While the dairy industry cheered the news, some lawmakers had a cow. Republican Sen. Mike Lee of Utah introduced legislation that would skim funding from the FDA, curdling its efforts to review milk marketing.

“Consumers are not deceived by these labels,” Lee told Roll Call last week. “No one buys almond milk under the false illusion that it came from a cow. They buy it because it didn’t come from a cow.”

Wisconsin Democrat Tammy Baldwin, meanwhile, called the legislation “an attack on dairy farmers,” Roll Call noted.

The Senate ultimately voted 14-84 to defeat the measure.

The National Milk Producers Federation applauded the vote, writing in a statement (PDF):

Today’s vote should send a very strong message to food marketers who have long been ignoring FDA’s food labeling standards by inappropriately using dairy terms on products that do not contain any dairy. Those days are numbered.

For now, almond-milk maker Hood is trying to mop up its mess from inappropriately using actual dairy in its product. The company noted that the tainted almond milk is not harmful unless a drinker has a sensitivity or allergy to dairy. At the time of the recall notice, there was one report of a consumer having an allergic reaction from the muddled milk. That person did not require medical attention.

In an email to CBS News, a Hood representative explained the situation, writing:

Although the almond milk is processed on a separate line and filler and we confirmed that the allergen-control protocol [sic] all standard validation testing was conducted in accordance with our allergen-control program, this particular batch of almond milk was contaminated with one container of milk through an employee error. Hood made the decision to recall all of the product from this batch as a precaution.

To get specifics on which almond milk cartons are being recalled, you can see Hood’s announcement here.