New Waxy Coating on Lettuce & Other Produce

by Catherine Haug, January 15, 2011; updated January 16, 2011,  January 23, 2011, and February 8, 2011

Thanks to Shelli R. for this article on Reality Blog: Dude, Isn’t that Wax on Your Apple? (1), and 1-minute You Tube Video: Plastic Lettuce (3). She researched this after finding it on red leaf, bib, and romaine lettuce at the Safeway in Polson.

This is not the all-natural, edible wax typically applied to apples – carnauba or shellac – which is easily washed off with cold water. This is synthetic plastic made from petroleum and other questionable sources as well as animal sources. And it’s applied to more foods than apples. You can find it even on lettuce, such as the head of Romaine in the video.

It is possible that what may look like an applied film on lettuce may actually be a natural phenomenon called “epidermal peel” or “rib raw” created by the lettuce to protect its rib (stem) from damage resulting from temperature changes, especially frost, according to Tom, the produce manager at Bigfork Harvest Foods (Jan 16 update). This phenomenon is similar to chapped lips resulting from cold weather, according to Dr. Mercola’s recent article: That isn’t wax on your Organic apple (4) (Feb 8 update).

1/16 & 1/23/12 updates: See What about organics section below.


According to the FDA, this practice is an approved method of protecting fresh foods from contamination by pathogenic microbes after harvesting, and it’s called “modified atmosphere packaging (MAP)”. It’s not just or plastic container a type of bag into which the produce is placed then filled with nitrogen and sealed. MAP also includes plastic films sprayed directly on the food. From the FDA report Microbiological Safety of Controlled and Modified Atmosphere Packaging of Fresh and Fresh-Cut Produce (1,2):

Edible biodegradable coatings are yet another variant of the smart film technology, where a film is used as a coating and applied directly on the food(Guilbert and others 1996; Francis and others 1999). Wax has been used in China since the 12th and 13th centuries as an edible coating to retard desiccation of citrus fruits, and in the last 30 years, edible films and coatings made from a variety of compounds have been reported. …

Guilbert and others (1996) and Baldwin (1994) have extensively reviewed some of the newer edible films (see Tables VI-3 and VI-5). These films are gaining popularity due to both environmental pollution and food safety concerns (Padgett and others 1998). However, a number of problems have also been associated with edible coatings. For example, modification of the internal gas composition of the product due to high CO2 and low O2 can cause problems such as anaerobic fermentation of apples and bananas, rapid weight loss of tomatoes, elevated levels of core flush for apples, rapid decay in cucumbers, and so on (Park and others 1994).

Edible films may consist of four basic materials: lipids, resins, polysaccharides and proteins (Baldwin and others 1995). Plasticizers such as glycerol as well as cross-linking agents, antimicrobials, antioxidants, and texture agents can be added to customize the film for a specific use (Guilbert and others 1996). Plasticizers have the specific effect of increasing water vapor permeability. Therefore, their addition must be considered when calculating the desired water vapor properties of each specific film, since too much moisture can create ideal growth conditions for some foodborne pathogens. The most common plasticizer used to cast edible films is food-grade polyethylene glycol, which is used to reduce film brittleness (Koelsch 1994).”

What’s in the sprays?

Plasticizers are additives that increase the plasticity or fluidity of a material. there are many different chemical plasticizers including phthalates, which are known and suspected carcinogens commonly used in shampoos and cosmetics

Polyethylene glycol, also known as PEG,  is one of the plasticizers used. It has a long history of use in personal care products (lotions, etc.), and is also used as a medical laxative. From eHow on polyethylene glycol safety (5):

“Side effects of polyethylene glycol normally affect the digestive system due to the laxative nature of the medication. These effects include nausea, bloating, gas and stomachache. … Allergic skin rashes develop in some patients.”

From Wikipedia (6):

“PEGs contain potential toxic impurities such as ethylene oxide and 1,4-dioxane. PEGs are nephrotoxic…” [Nephrotoxic means toxic to the kidneys.]

See the Reality Blog post: Dude, Isn’t that Wax on Your Apple? (1) for lots more supposedly safe chemicals that may be present in these sprays, taken directly from Table III in the FDA report (the list is too long and complicated for repeating here).

What about Organic produce?

Jan 16 update: Could plastic sprays be used on Organics? Would an applied coating fall under the “packaging” rules?  These answers depend on the Organic standards, which vary by country. I’m researching this and will update when I know more!

Jan 23 update: From the Organic Consumers Assocation (OCA): See links to the Electronic Code of Federal Regulation: Organics, especially Section 205.605 regarding “nonagricultural substances may be used as ingredients in or on processed products labeled as “organic” or “made with organic…” Includes lists for non-synthetics and synthetic substance that may be used. Plasticizers and polyethylene glycol are NOT in the list, but there some questionable synthetics including:

  • Calcium hypochlorite; Chlorine dioxide; and Sodium hypochlorite used for disinfecting and sanitizing food contact surfaces, but residuals must be below specified limits
  • Eythlene used for postharvest ripening of tropical fruit (like bananas) and degreening of citrus.
  • Cyclohexylamine,  Diethylaminoethanol, and Octadecylamine which can be used only as a boiler water additive for packaging sterilization.

Meanwhile, if you want to be proactive, contact the Organic Consumers Association (OCA) and the Organic Trade Association (OTA) about the use of applied coatings on Organic produce.

Contact the FDA: Center for Food Safety and Applied Nutrition.

Also write to our elected officials, especially Sen. Tester, as he is an Organic farmer. Go to Contact our Government for Federal, State, Flathead & Lake Counties.

What can you do to avoid this coating on your produce?

The obvious solution is to grow your own fresh produce, or buy from local growers you trust.

If you buy a product treated to one of these coatings, you can remove the coating (as was done with the romaine lettuce leaf in the video), but there’s no guarantee that the food didn’t take up some of the chemicals from the coating into its cells.

If you want to be an activist, write to your legislator(s) to demand they look into this practice and do something about it.


  1. Reality Blog: Dude, that isn’t wax on your apple
  2. Microbiological Safety of Controlled and Modified Atmosphere Packaging of Fresh and Fresh-Cut Produce
  3. YouTube: Plastic Lettuce
  4. Mercola: That isn’t wax on your Organic apple
  5. eHow on polyethylene glycol safety
  6. Wikipedia on Polyethylene Glycol (PEG)

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