According to NutraSweet, increasingly large quantities of counterfeit neotame high-intensity sweetener are being produced in China, and being passed off as the genuine article.
"Counterfeit neotame of doubtful identity and poor quality is becoming an issue in the marketplace, particularly in China," said NutraSweet chief executive officer Craig Petray.
NutraSweet is the exclusive manufacturer of neotame, and holds numerous processing and application patents in more than 50 countries.
The extensive patent estate extends through 2020.
Neotame is a derivative of aspartame, which is said to be around 7,000 to 13,000 times sweeter than sugar, but to have a sugar-like taste and no calories.
It is also said to be 30 to 60 times sweeter than aspartame, depending upon the food application.
The low-cost sweetener is also one of the fastest-growing in the market, with 50 per cent annual growth since 2002, according to the company, and this has made it popular among counterfeiters looking to turn a quick profit from this success.
The problem of counterfeit material being manufactured on a small scale and sold in the Chinese market was first noticed two years ago by NutraSweet officials.
Counterfeit neotame has been marketed at trade shows and promoted in trade advertising, the company said.
"This situation is confusing our customers, who sometimes accidentally purchase the counterfeit material with no reassurance of its quality," said Petray.
"We have an active program to monitor this counterfeit material and our examination reveals it to be of substandard quality.
In many cases, the product is not the chemical composition of neotame at all, nor does it pass established safety standards established by the Joint FAO/WHO Expert Committee on Food Additives (JECFA) and the Food Chemicals Codex (FCC)."
NutraSweet said that customers should buy their neotame sweetener directly from the company or an authorized distributor.
Petray told FoodNavigator-USA.com that "the Chinese-produced counterfeit neotame is infringing our molecule patent in China" and that it "often contains alarming amounts of unknown impurities".
He said that the counterfeit neotame "is produced in China by a few companies and sold by dozens of small traders".
"We are working with the appropriate government agencies to stop the manufacture of the infringing material."
But he stressed that the problem of counterfeit material is, for now at least, restricted to China.
"We have not seen the issue of counterfeit neotame outside the Chinese market."
Demand for sweeteners in the Chinese market is growing steadily as incomes rise and consumers adopt more western lifestyles.
Britain's Tate & Lyle recently announced plans for a new production facility for its Splenda sucralose brand in Singapore to build on this popularity, but it, too, has been hit by counterfeiting.
In April last year Tate & Lyle took legal action against three Chinese manufacturing groups and 18 companies involved in importing and distributing sucralose - although they were targeting the US rather than the local market.