The Science and Safety of Food Additives

It was more than 20 years ago that the U.S. added folic acid to flour as a public health policy in an effort to reduce the risk of neural tube defects (NTD) in newborns. Since that time, the prevalence of NTD has decreased by nearly 30 percent. Many scientists also suggest that, in addition to adding folates to the food supply, increased consumption of choline and vitamin B12 may be important in reducing NTD risk.

Indirect Food Additives

Indirect food additives may be found in foods as a result of processing, packaging migration, or even handling. Examples include preservatives that are components of packaging materials, which may migrate into the food via contact and during storage. Importantly, the safety of food contact surfaces must be rigorously assessed before they are permitted for usage.

The 1997 Food and Drug Modernization Act established a food contact notification process. Sponsors of this notification must provide extensive and relevant safety information, such as: a) migration or extraction data, as determined by specific guidances; b) an array of published and unpublished safety data; and c) evaluation of safety based on consumption of residues or extractables from the material.

Some of the packaging materials that may include indirect food additives include metal-polymer coatings applied in retort pouches, paper-polymer coatings used in many polymeric materials, and an array of polyolefins used in rigid, semirigid, and plasticized packages, polystyrene (nylon), and ethylene vinyl acetate (a type of plastic) applied to acrylic and phenolic packaging materials.

Color Additives

Food colorants are subject to extensive safety assessments as noted in the 1960 Color Additives Amendments to the 1958 Food, Drug, and Cosmetic Act. These substances are classified as either certified or exempt colors. From a consumer perspective, certified colors are synthetic, whereas exempt colors, which are exempt of certification, are considered natural. Certified colors, which may be dyes (water soluble) or lakes (fat soluble), are typically resistant to degradation by light, pH, and temperature. On the other hand, exempt colors, such as those derived from insects (e.g., cochineal), plants (e.g., beets, grape skins), fungi (e.g., Aspergillus, mushrooms), microalgae (e.g., an array of pigments) and mineral sources (e.g., titanium dioxide), have less coloring power in that they are more subject to degradation when exposed to light, pH (acid or alkaline), and elevated temperatures.

More than 40 years ago, several reports from a single research center suggested that the yellow color tartrazine contributed to the development of hyperkinesis among children. Despite several follow-up clinical studies that rejected this relationship, FDA promulgated a regulation that the use of this lemon-yellow azo dye (aka FD&C Yellow 5) must be declared on food labels and even on pharmaceutical agents.

About 10 years ago, several studies out of the United Kingdom suggested the consumption of artificial colors led to attention deficit hyperactivity disorder among children. While FDA commented that there wasn’t sufficient evidence proving that foods with artificial colors caused hyperactivity in the general population, the food industry gradually reduced the use of such colors, while increasing efforts to identify “natural” replacement pigments.

It’s important to note that, ironically, many natural sources of potential food pigments are associated with toxins. For example, a selected number of ascomycetous fungi species produce specific polyketide pigments along with toxic metabolites, such as ochratoxin A and penicillic acid. On the other hand, the terms azaphilones, anthraquinones, oxopolyenes, and naphthoquinoes, which also have some pharmacological properties, may not appeal to consumers.

Flavoring Agents

Within the United States, FDA has a memorandum of understanding with the Flavor Extract and Manufacturers Association (the “other FEMA”). This body of experts publishes its safety findings every two years. Its most recent GRAS (Generally Recognized as Safe) document, released in December 2019, is the 29th report that reflects extensive safety review of flavoring agents. Since 1970, FEMA experts have reviewed the safety of approximately 3,000 flavoring substances. Flavoring agents are typically small molecules that are used in very small doses, usually less than 1 percent of the of product formulation. These reviews leveraged an array of external resources that contribute to exposure assessment and process control.