Following recent scares over food contaminated with the banned substance melamine, a number of processors - including Nutracea, Mission Foods and Tyson Foods - have reiterated that their ingredients are not, or will no longer be, sourced from China. Such a reaction could further hinder the potential of Chinese food exports, as global companies move to find new ingredients sources that are not associated with the growing consumer backlash. Nutracea in particular was keen to stress that its products were solely reliant on sourcing raw materials from the US. "Nutracea does not currently, or in the past source any of its raw materials from China or anywhere outside the US," company vice president Margie Adelman told AP-FoodTechnology.com. The backlash began earlier this year with the discovery that melamine used in wheat proteins sourced from China had made its way into some pet foods. Hundreds of dogs and cats either died or suffered health problems as a result. The scare increased in the US when it was found to have entered the human food chain after pet food scrap was used as a feed supplement at a number of hog and chicken farms. Melamine is an industrial chemical found in plastics. The US found that the chemical had been fraudulently added to wheat gluten and rice protein from China. The country has now banned its exporters from using the chemical as an additive to boost protein levels in feeds. Following the outbreak, the US Department of Agriculture detained 46 Chinese shipments of vegetable proteins. With no testing certification yet received to confirm melamine is present, all restricted shipments continue to remain under detention. Though the USDA accepted earlier this month that humans faced a low health risk from consuming meat that contained melamine and melamine-related compounds, the reputation of China's food and feed products continue to be undermined by the incident. According to a recent report by the Washington Post, the USDA last month seized over 1,000 shipments of tainted Chinese dietary supplements, toxic cosmetics and counterfeit medicines. The heightened restrictions have also seen fruits, bean curds, teas and even candy being seized upon entry to the US. Regulators on the other side of the Atlantic are also keeping a stricter eye to prevent similar food safety problems from occurring. As a result, China's government have started to review thier food safety practices to prevent further health scares. Hong Kong last week announced a review of its food safety protocols and has proposed tightening regulations on fish, vegetable and fruit products. The new local safety bill will impose controls on pesticide residues, along with requiring health certification on any mainland China products that enter Hong Kong. Authorities in Shanghai have also enacted similar measures with the recent formation of a rapid response food testing system, designed to step up the tracking and prevention of harmful food and beverage products. Both cities are major ports for China's exports.