U.S. inflation remains tame at the consumer level, but prices at the producer level jumped unexpectedly in March, largely on higher food and service sector prices.

The U.S. Labor Department said Friday the producer price index increased 0.5 percent in March after slipping 0.1 percent in February. That was the largest increase since June last year, Reuters reported.

Economists polled by Reuters had forecast prices received by the nation's farms, factories and refineries to rise just 0.1 percent in March.

Food prices jumped 1.1 percent, the largest increase since May, after rising 0.6 percent in February.

Food prices were pushed up by a surge in the cost of pork, which saw its largest rise since August 2008. Sausage, deli meat and boxed meat prices rose by the most since August 1980, Reuters reported.

Producer prices excluding volatile food and energy costs rose 0.6 percent, the biggest gain since March 2011. The so-called core PPI for final demand had declined 0.2 percent in February.