Commercial disodium inosinate may either be obtained from bacterial fermentation of sugars or prepared from animal products. The Vegetarian Society reports that production from meat or fish is more widespread, but the Vegetarian Resource Group reports that all three "leading manufacturers" say that they use fermentation.
As a relatively expensive product, disodium inosinate is usually not used independently of glutamic acid; if disodium inosinate is present in a list of ingredients, but MSG does not appear to be, it is possible that glutamic acid is provided as part of another ingredient or is naturally occurring in another ingredient like tomatoes, Parmesan cheese, or yeast extract.
Origin
Inosinate is naturally found in meat and fish at levels of 80–800mg/100g. It can also be made by fermentation of sugars such as tapioca starch.
Some sources say that industrial levels of production are achieved by extraction from animal products, making E631 non-vegetarian. However, owing to the sufficient availability and stable quality of raw materials, large-scale production of disodium inosinate is currently predominantly realized via bio-fermentation processes of Corynebacterium Stationis. Major disodium inosinate manufacturers include Ajinomoto, CJ CheilJedang, as well as some Chinese companies such as Sinofi. An interview by the Vegetarian Resource Group reports that all three "leading manufacturers" (one being Ajinomoto) say that they use an all-vegetarian fermentation process. Producers are generally open to providing information on the origin. E631 is in some cases labeled as "vegetarian" in ingredients lists when produced from plant sources.
Toxicology and safety
In the United States, consumption of added 5′-ribonucleotides averages 4mg per day, compared to 2g per day of naturally occurring purines. A review of literature by an FDA committee found no evidence of carcinogenicity, teratogenicity, or adverse effects on reproduction.
In 2004, disodium inosinate was proposed to be removed from the food additive list by Codex Alimentarius Commission. This change did not go through: it is still present in the 2009 Codex Alimentarius list.
↑Disodium 5′-guanylate and Disodium 5′-inosinate, K. Ekelman and K. C. Raffaele, Additives Evaluation Branch, Division of Health Effects Evaluation, Center for Food Safety and Applied Nutrition, Food and Drug Administration, Washington, DC, USA and other