Within food at home, four of the six major grocery store food group indexes decreased in May, led by nonalcoholic beverages, which fell 1.1 percent.
The index for dairy and related products, which was flat in April after several months of declines, again finished lower, falling 0.8 percent in May.
Also finishing lower was the index for cereals and bakery products, which fell 0.4 percent, and the index for food at home, which declined 0.3 percent.
The index for meats, poultry, fish, and eggs was flat.
The only grocery store food group index to rise during May was fruits and vegetables, which increased 0.4 percent after a 1.4 percent decline in April.
Over the past 12 months, the food at home index has risen 0.8 percent, with the fruits and vegetables index increasing the most over that span, 2.1 percent.
After two consecutive months of declines, the overall Consumer Price Index increased in May, rising 0.1 percent. Over the past 12 months, the index has increased 1.4 percent.