Developments in Brief : It’ll Be a Long Summer Without Raw Oysters

The current issue of the monthly Harvard Medical School Health Letter reminds readers that May is the first of four consecutive months without the letter “r” in its name. May through August are months during which raw oysters should not be eaten, according to an obscure if sensible custom.

It is during these warm months that shellfish most readily support the growth of disease organisms. Contaminated clams and oysters can cause hepatitis and typhoid, as well as less serious problems, like diarrhea.

The “r” rule has been relaxed in recent years as confidence has grown in the regulation of harvesting, holding and purifying shellfish. But, the newsletter says, current standards are either not high enough or not being adequately enforced.