Chinese authorities have found 157 dead pigs in a river, state media said Wednesday, underscoring the country's food safety problems a year after 16,000 carcasses were discovered in Shanghai's main waterway. The dead porkers were recovered from the Gan river in Jiangxi, which supplies drinking water to the provincial capital Nanchang, the official news agency Xinhua said. Tests showed that the tap water remains safe for drinking, it said, citing Nanchang authorities. The Gan is a tributary of the Yangtze, one of China's main waterways. "Another 20 pigs have been fished out of the Gan River, for a total of 157," state broadcaster CCTV said on an account on Sina Weibo, a Chinese version of Twitter. Photos posted by CCTV showed staff in white clothing and face masks inspecting carcasses lined up on a riverbank. Ear tags indicated the animals came from Zhangshu, which is part of Yichun city in the central Chinese province, CCTV said, citing Jiangxi's agriculture department. An official with the Yichun agriculture bureau surnamed Zhao told AFP it was unclear where the pigs originated, while Zhangshu authorities could not immediately be reached. A year ago China was stunned by the appearance of more than 16,000 dead pigs floating along parts of the Huangpu river which flows through Shanghai -- one of a series of food-safety scandals in recent years. No official explanation was given for the incident, which hugely embarrassed China's commercial hub. Last May police detained 900 people for crimes including selling rat and fox meat as beef and mutton. And in 2008 six babies died and 300,000 others fell ill in a massive scandal involving contaminated milk powder. Public concern about food safety is high. In his address to China's parliament this month Premier Li Keqiang pledged to "apply the strictest possible oversight, punishment and accountability to prevent and control food contamination and ensure that every bite of food we eat is safe".