Isopropyl Alcohol in Soft Drinks

In September 2005, a "panel of scientific experts" at the European Food Safety Authority concluded, "after examining a dossier on propan-2-ol (isopropanol, IPA) put forward by the European Flavour and Fragrance Association (EFFA), [that] soft drink makers should propose limits for heavy metals and aromatic hydrocarbons used as carrier solvents for flavouring preparations in soft drinks." 

The EFSA said that the Acceptable Daily Intake (ADI) of "2.4 mg/kg bw would be reached for a 60 kg [approximately 132-pound] adult by the daily consumption of 240 ml of soft drink which is less than a normal sized can or bottle." 

The EFSA stated that an "estimate has been made of the potential intake of propan-2-ol from all sources for UK adult consumers, including the assumption that it is used in soft drinks at 600 mg/l. The mean potential intake was estimated to be 1.3 mg/kg bw/day, i.e. below the ADI. However, the estimated 97.5th percentile of potential intake from all sources in consumers was 5.4 mg/kg bw/day, exceeding the ADI. Exposure estimates based only on the consumption of regular carbonated drinks in teenagers from 5 EU cities, assuming a concentration of 600 mg/l, lead to potential intake of 1.4 mg/kg bw/day at the mean and up to 10 mg/kg bw/day at the 97.5th percentile." 


 * According to the Occupational Safety & Health Administration (OSHA), U.S. Department of Labor, the Acceptable Daily Intake (ADI) of isopropyl alcohol is 400 ppm (400 parts in 1 million)/400 mg/l.

What the EPSA summary did not report is that its conclusions were based only on "chronic inhalation studies in rats and mice" and that were "no chronic toxicity and carcinogenicity studies by the oral route." (page 5)

The EFSA summary opinion is available here. The full 10-page opinion is available here (pdf).

Food Additives Status List
The Office of Food Additive Safety (within the Center for Food Safety and Applied Nutrition in the U.S. Department of Agriculture) issues the Food Additives Status List, which "includes use limitations and permitted tolerances for each additive." According to the March 2006 Food Additives Status List:


 * Isopropanol, isopropyl alcohol - SOLV, REG, <250 ppm as residue in modified hop extract - 172.560; <50 ppm as residue - In mfr of spice oleoresins - 173.240; 6 ppm - In mfr of lemon oil - 173.240; 2% by wt - In hop extract as residue from extraction of hops in mfr of beer - 173.240; AF, REG, GMP, Comp of defoaming agent for processing beet sugar and yeast - 173.340; SANI, REG, GMP, Adequate drainage - May be used on food processing equip and on food-contact surfaces - 178.1010(b)(17); SANI, REG, < 40 ppm Adequate drainage; May be used on food processing equip and on glass containers for holding milk - 178.1010(b)(7)


 * Note that no mention is made of its use as a carrier solvent for flavorings in the manufacture of soft drinks.

KEY: AF = "Antifoaming (or defoaming) agent"; GMP = "In accordance with good manufacturing practices; or sufficient for purpose; or quantity not greater than required"; REG = "Food additives for which a petition has been filed and a regulation issued"; SANI = "Sanitizing agent for food processing equipment"; and SOLV = "Solvent".

About Isopropyl Alcohol
Isopropyl alcohol (also known as Pseudo propyl alcohol; 2-propanol; dimethyl carbinol; isopropanol; sec-propyl alcohol; persprit; secondary propyl alcohol; IPA; propan-2-ol; alcohol isopropylicus; and petrohol) is a clear, colorless, toxic, volatile, flammable liquid. It has a slight odor "resembling a mixture of ethanol and acetone." Isopropyl alcohol is soluble in water, alcohol and ether "in all proportions at 20°C." It is also soluble in acetone, benzene and chloroform, but insoluble in salt solutions. 

Uses
It is used as a dehydration agent, a defrosting agent, an antiseptic, and as both an extraction solvent and a process solvent. Isopropyl alcohol is commonly found in many cosmetics and food products.

As a process solvent, isopropyl alcohol is used for the "extraction and purification of natural products, such as vegetable and animal oils and fats, gums resins, waxes, colours, flavourings, alkaloids, vitamins, kelp and alginates" and as carrier solvent in the manufacture of food products. 

It is used in "antifreeze products; solvent for gums, shellac, essential oils, in quick drying oils, creosote and resins: extraction of alkaloids; in quick drying inks; in denaturing ethyl alcohol; in body rubs, hand lotions, after-shave lotions, cosmetics and pharmaceuticals; in manufacture of acetone, glycerol, isopropyl acetate; antiseptic; rubefacient pharmaceutic aid (solvent) (in concentrations up to 70%) (Ellenhorn, 1988)." 

It is also used in the conversion of cocaine base to cocaine hydrochloride. 

Absorption, Metabolism & Excretion
"80% of an oral dose is absorbed within 30 minutes. Absorption is complete within 2 hours although this may be delayed in a large overdose (Ellenhorn, 1988)." 

"20 to 50% of an absorbed dose is excreted unchanged. Most isopropyl alcohol is oxidized in the liver by alcohol dehydrogenase to acetone, which is probably further metabolized to acetate, formate, and finally carbon dioxide. Acetone may contribute to the CNS depression seen in isopropanol poisoning. ...

"Acetone is slowly eliminated by the lung (40%) or kidney. Clinically insignificant excretion occurs into the stomach and saliva (Teramoto, 1987).

"Related ketoacids are not produced in sufficient quantities to cause a severe metabolic acidosis." 

Safety
Isopropyl alcohol is incompatible with: "Heat, flame, strong oxidizers, acetaldehyde, acids, chlorine, ethylene oxide, hydrogen-palladium combination, hydrogen peroxide-sulfuric acid combination, potassium tert-butoxide, hypochlorous acid, isocyanates, nitroform, phosgene, aluminum, oleum and perchloric acid." 

When ingested, isopropyl alcohol can cause: "drowsiness, unconsciousness, and death. Gastrointestinal pain, cramps, nausea, vomiting, and diarrhea may also result. The single lethal dose for a human adult = about 250 mls (8 ounces)." 

Chronic exposure to isopropyl alcohol "may cause skin effects." It can also aggravate pre-existing conditions: "Persons with pre-existing skin disorders or impaired liver, kidney, or pulmonary function may be more susceptible to the effects of this agent." 

How Produced
Isopropyl alcohol is a synthetic: "Prepared from propylene, which is obtained in the cracking of petroleum or by the reduction of acetone (Budavari, 1996)." Manufacturers and importers include Shell Chemicals, British Petroleum, and Mobil Oil. 

Reports

 * "Opinion of the Scientific Panel on Food Additives, Flavourings, Processing Aids and Materials in Contact with Food on a request from the Commission related to Propan-2-ol as a carrier solvent for Flavourings," Question Number EFSA-Q-2003-136, Adopted February 23, 2005, EFSA Journal (2005)202, 1-10.
 * "Opinion of the AFC Panel related to Propan-2-ol as a carrier solvent for Flavourings," adopted February 3, 2005; last updated June 3, 2005.

Related SourceWatch Resources

 * Benzene in Soft Drinks
 * oil industry
 * processed food industry