Bottled water, tea and energy drinks are being sold under the Wahaha brand in parallel with authorized products produced by the joint venture, said Danone, the maker of Danone yogurt and bottler of Evian and Volvic water.

Danone's accusations follow a lengthy report Mr. Zong released on a Web site that accused Danone of trying to take control of businesses he owns and saying terms of their existing agreements are unfair.

The stakes for both sides are high. Danone's main toehold in China is Wahaha, and the accusations challenge the integrity of one of China's most famous consumer brands, which remains closely identified with its founder, Mr. Zong.

In his comments, the 61-year-old Mr. Zong pitted himself as a defender of China against Danone. Mr. Zong said it is unfair that Danone has separate joint ventures making juice and milk under other brand names that compete with Wahaha-branded products. "So these terms are unfair and need to be revised. Either you call off the restrictions on us, or I add restrictions on you,"Mr. Zong said.

Emmanuel Faber, president of Danone Asia Pacific, asserted that Wahaha products are being made at factories owned and managed by Mr. Zong's family interests that haven't been approved under the joint venture. Some of these products are secretly fed into the joint venture's existing sales network, the Danone executive said; others are sold separately.

In addition, he said, some factories designated as third-party manufacturers are secretly owned by Mr. Zong's family.

Mr. Faber played down the nationalistic tone of Mr. Zong's online commentary, saying it is an attempt to use "public leverage to serve personal interest."The Danone executive added, "I would not derive from this particular situation that the environment in China is becoming more hostile."

To sign up for The Wall Street Journal Briefing please visit http://www.briefing.wsj.com/hktdc.