Al Capone and his Brother Ralph are responsible for milk expiration dating.

It was reported in the early 1930s that one of Alphonse (Al) Gabriel "Scarface" Capone's Chicago family members became sick from drinking milk that wasn't fresh... but had not soured yet. At that time, there were no controls on milk production or distribution.
That’s probably the reason he wanted to buy a dairy processing and bottling business. Al had been trying to diversify his investments in legitimate businesses for some time, even while consolidating his brewing, distilling, and distribution concerns. 

As Al put it himself; "You gotta have a product that everybody needs every day. We don't have it in booze. Except for the lushes, most people only buy a couple of fifths of gin or scotch when they're having a party. The working man laps up half a dozen bottles of beer on Saturday night, and that's it for the week. 

But with milk! Every family, every day, wants it on the table. The people on Lake Shore Drive want thick cream in their coffee. The big families out back of the yards have to buy a couple of gallons of fresh milk every day for the kids. Do you guys know there's a bigger markup in fresh milk than there is in alcohol? Honest to God, we've been in the wrong racket right along."

Raffaele (Ralph "Bottles") James Capone, Al Capone’s older brother, with the help of Murray "The Hump" Humphreys, Frankie Diamond, and Diamond's brother, Johnny Maritote, who was married to Al’s sister, Mafalda bought Meadowmoor Dairies at 1334 South Peoria Street in Chicago on May 4, 1932. Ralph Capone got the nickname "Bottles" not from the Capone bootlegging empire but from his bottling milk at Meadowmoor and lobbying the dairy industry to date milk. Al Capone and Ralph are responsible for milk expiration dating in Chicago in 1933. Ralph took the reigns on milk dating once Al was incarcerated in Atlanta U.S. Penitentiary in May 1932. Then he was sent to  Alcatraz in late August of 1934.

“My grandfather [Ralph Capone] went to Springfield, Illinois, totally on his own, and he lobbied the milk industry to start putting the date that they bottled the milk right on the bottle,”  said Deirdre Marie Capone. “Then people would make up their own mind if it was too old.”

Ralph was most famous for being named "Public Enemy Number Three" when his younger brother Al was "Public Enemy Number One."

Ralph planned to undercut local fixed dairy pricing by the Pure Dairy Association Union. Ralph had milk shipped in from Wisconsin dairies and bottled by Meadowmoor. Chicago dairy retailers refused to sell Meadowmoor milk. In those days, milk was sold by the dairy companies to vendors. The vendors operated their own trucks, and they resold the milk to retailers. The retailer then sold to the general public. The vendors also refused to deliver Meadowmoor milk to retailers. 

Chicago gangsters were accused of responding by bombing Pure Dairy Association plants resulting in a literal Milk War in 1932-33.

Four years later, in November of 1936, Cook County State’s Attorney Investigator, Tubbo Gilbert, was indicted for helping the Teamsters fix retail milk prices in Chicago. By that time, the Chicago teamsters were little more than an extension of the Chicago mob. The scandal involved Dr. Herman Bundesen of the Chicago board of health and officials of local 753 of the Milk Drivers Union. The indictment read that they had conspired to fix the amount of milk delivered in the city to squeeze the smaller distributors out of business, leaving only Meadowmoor Dairies.

Despite a mountain of evidence, the case went nowhere. States Attorney Courtney refused to bring it to court and refused to allow Tubbo Gilbert to resign. 

It's also interesting to note that a few years after the price-fixing scandal died away, Murray Humphreys managed to drive most of his competitors in the dairy business out of the market by following through with Al's idea of eating fresh dairy products. 

Ralph insisted, and you've read how persuasive the Capones' could be, that a law is passed that Grade “A” milk could not be sold as fresh milk more than 72 hours after it left the cow. He convinced the Chicago City Council to pass a law in 1933 that clearly stamped the date on milk bottles where the consumer could read and understand it. The practice is now required of all meat, fish, and dairy distributors across the country. 

Meadowmoor became the Richard Martin Milk Company in 1961, although the Meadowmoor name still appeared on their milk containers for some time after '61.

It was likely that the Capones’ had already cornered the market on equipment to stamp expiration dates on bottles, and the passage of the legislation would help him take over the Chicago milk market.

The United States Supreme Court Case No. 56:
MILK WAGON DRIVERS UNION OF CHICAGO, LOCAL 753 v. MEADOWMOOR, (1941)
Decided: February 10, 1941

Compiled by Dr. Neil Gale, Ph.D. 
Contributor, Deirdre Marie Capone, Al's grandniece.