Messages on micro blogs targeting possibly contaminated laosuannai (a kind of condensed yogurt) and jelly has reignited concerns over food security, but dairy, jelly producers and dairy association denied the accusations.

Zhao Pu, an anchor with China Central Television (CCTV), warned people - especially children - to keep away from condensed yogurt and jelly on his Sina micro blog Monday. An investigative journalist Zhu Wenqiang with The Economic Observer hinted on his Sina micro blog the aforementioned food may contain ingredients from leather products such as discarded shoes, citing a "friend from CCTV."

Both Zhao and Zhu deleted related posts later Monday.

Netizens suspected that the food may be added with industrial gelatin, which are made from leather products.

Song Kungang, head of the China Dairy Industry Association, told people.com.cn, the website of People's Daily, that condensed yogurt by "major dairy firms" use edible gelatin, so the products meet the national standards and by no means contain industrial gelatin. But he did not reveal which brands are included in the "major dairy firms" and said he had no idea how to distinguish yogurt with industrial gelatin and those with edible gelatin.

"What we add into dairy products is edible gelatin, which strictly conforms to national standards," said an insider from a leading state-owned dairy company who spoke on the condition of anonymity. "Edible gelatin is mainly collagen extracted from animal skin or bones, and so is perfectly healthy."

Qinqin Inc, a jelly producer, responded that the legal thickener in jelly is carrageenan – an edible additive that makes jelly fresh, crisp, and transparent. Gelatin do not have the same effect.