Addendum to Weiner, M.L. (2016) Parameters and Pitfalls to Consider in the Conduct of Food Additive Research, Carrageenan as a Case Study. Food Chemical Toxicology 87, 31-44.

• Analyze carrageenan for identity, purity and molecular weight for adequate interpretation of in vivo and in vitro studies.
• Understand the binding of carrageenan to protein in clearly specifying methods and interpreting results.
• Protein binding of carrageenan to enzymes and protein substrates can be affected by the order of addition.
• Study methods should be complete with all relevant details, including an understanding of the test material physical and chemical properties.

This paper is an addendum to a 2016 paper outlining pitfalls and parameters to consider in the conduct of food additive research with carrageenan (Fd. Chem. Tox. 87, 31–44 (2016)). The literature on the food additive, “carrageenan,” contains many publications which either erroneously misuse the name, carrageenan, for a sample which is not carrageenan, but “degraded carrageenan” or “poligeenan” and also conduct studies without understanding the physical/chemical properties of carrageenan. Degraded carrageenan and poligeenan are not food additives and have a completely different physical/chemical and toxicological properties from carrageenan. Two recent publication examples, one in vivo and one in vitro, demonstrate the serious misunderstanding promulgated by incorrect sample identity/purity and poor study conduct. These new publication examples reiterate the problems in the literature summarized by the Weiner (2016). It is important to have thorough, rigorous peer review of all studies using carrageenan in vivo or in vitro.