The prices of farm produce in 36 major Chinese cities slightly retreated for a second straight week due to rising supplies, the Ministry of Commerce said on Tuesday.

The wholesale prices of 18 kinds of vegetables went down 4.6 percent last week from a week earlier, while the prices of eight aquatic products shed 0.4 percent.

The cost of eggs dipped 0.1 percent week on week, but the price of pork, the country's staple meat, gained 0.5 percent, the ministry said.

Meanwhile, the prices of major production materials, including nonferrous metals, rubber and fuel, continued to ease last week, marking the seventh straight weekly decline.

Food prices account for about one-third of the prices used to calculate China's consumer price index (CPI), a main gauge of inflation.

China's CPI growth slowed to 2.1 percent in May.