Coatings For Fresh Produce

A small sign hanging above the produce in a local supermarket reads, “Fruits and vegetables have been coated with food-grade vegetable, petroleum, beeswax, and/or lac-resin based wax or resin to maintain freshness… No fruits or vegetables have been coated with animal-based wax”. The sign is the result of efforts by citizens groups demanding disclosure of ingredients in coatings used on fresh produce. The produce industry, citing the impracticality of constantly changing signs and claiming that disclosure would compromise the confidentiality of coatings ingredients, resisted these demands. The FDA regulation that emerged in 1994 is the result of a compromise between the two groups. Although the sign does disclose some information, it only tells part of a much larger story.1

The sign is not required by law to declare the additives put in produce coatings, some of which raise kashrus concerns. That doesn’t mean that coatings on fresh produce are not acceptable. This article will present information relevant to evaluating the kashrus of coatings.

First, a note about where the information came from: Coatings manufacturers, careful to guard trade secrets, are unusually tight-lipped about the ingredients they use. Jewish law, in any event, limits the credibility of company spokespeople, particularly when there is no way of verifying their claims.

Reading literature written by and for people in the produce industry is halachically similar to overhearing a conversation, and, in some instances, is reliable according to the parameters of maysiach l’fi tumo, which means that the person talking is unaware of the halachic significance of his report.2

Much of the literature comes out of government and academic research. Produce coatings extend the shelf life of fresh fruit and vegetables and, in some instances, make fruits and vegetables look more attractive. The technology is critical to agribusiness. The USDA has several scientists researching and developing more effective and less expensive coatings. These scientists, whose salary is paid for by tax dollars, consider it part of their job to speak to the public. Food Science departments also invest in research into produce coatings. The annual conference of the Institute of Food Technologists has featured sessions discussing progress in coatings manufacture from various materials.3

The most straightforward way of knowing what actually goes into produce coatings is by reviewing the product lines of major manufacturers. Those products typically contain two major components: the base, or resin, which is the majority ingredient of a coating (and which are broadly listed on the supermarket sign), and several different additives (which are left out).

In terms of bases, shellac (the “lac-based” resin referred to in the sign), and carnauba wax are by far the most commonly used. Shellac is a secretion of the lac bug, which is found in Thailand and India. Some kashrus agencies follow the ruling of Iggeros Moshe Yoreh Deah I:24, which offers several reasons why shellac is acceptable as a confectionary glaze.4

Carnauba wax is formed on the leaves of the Brazilian palm tree, from which it is mechanically removed. It is inherently kosher.5

A sucrose-ester base is also available on the market, but sold on a much smaller scale.6 Other likely materials include Candellila wax, also botanical in origin, cellulose based materials (botanical), and petroleum, which is inherently kosher. Beeswax is also considered inherently kosher.7

Research and development of new coatings bases include whey or casein-protein (dairy derivatives),8 wheat (chametz),9 rice-bran (kitnios), corn zein,10 acetylated monoglyceride11 (which can be either from a kosher vegetable or non-kosher animal source), or from a triglyceride emulsion12 (also from vegetable or non-kosher animal sources).13 Coatings containing these materials are not commonly, if at all, produced commercially.

As far as additives are concerned, information can be taken from the industrial product labels of the coatings. These labels are found on the coating containers in the produce packinghouses, where coatings are actually applied to fresh produce. These labels have ingredient declarations that list many of the additives found in coatings. These additives help the base be evenly dispersed and conform smoothly to the shape of the produce. Some of the additives can be of animal, vegetable, or dairy origin.

Morpholine oleate is an additive commonly found on ingredients labels. Morpholine is an innocuous ammonium based ingredient that is used to raise the pH. The “oleate” suffix indicates the presence of oleic acid, a fatty acid. Sometimes oleic acid is used for legal reasons (it’s necessary in the presence of morpholine) and in other applications it is an emulsifier, critical to the production of the coating.

An emulsifier helps a material like carnauba wax mix with water. The coating is sprayed onto fruits, which means that it must be in a water-solution.14

Stearic acid, another fatty acid, is also commonly added to produce coatings. This additive is a plasticizer, which means it increases the flexibility and adds toughness to a coating.

Fatty acids are one of the two major components of a fat or oil. Although some fatty acids can come from a vegetable source only, others, like oleic and stearic acids, can come from either a vegetable or an animal source. How do we know whether the oleic acid that companies are using is from the vegetable source or the animal source?

Some companies claim that they have used vegetable based oleic acids. A chemist from a major coatings manufacturer suggested that it is the “climate” to purchase vegetable-derived ingredients, and, therefore, kosher consumers can rest assured that oleic acid is from a vegetable source. On the other hand, tallow derivatives are typically cheaper than their vegetable counterparts.15 Although American companies do like to declare the use of vegetable-based ingredients for the health-conscious consumer, that possibility does not exist with fresh produce, since no comprehensive ingredient statement is provided to the retail consumer. One manufacturer acknowledged that additives such as oleic or stearic acid were not necessarily from kosher sources. When the non-kosher alternative is cheaper, and no affirmative duty compels manufactures to declare the origin of their ingredients, it is hard to assume that the oleic acid being used in coatings is from a vegetable source.

Whey (dairy) and soy (kitniyos) proteins are also often used as thickeners in produce coatings. Apparently the presence of dairy is not an allergen concern, nor it is an allergen concern that manufacturers are willing to risk. Finally, the coating solution sometimes contains alcohol (isopropanol or ethanol).16

Table I shows both the ingredients used in produce coatings and their typical proportions.17


Ingredient    Proportion
Water 65-80%
Alcohol (isopropanol and/or ethanol) 0-15%
Carnauba wax/shellac 15-18%
Oleic acid and other fatty acids 3-5%
Morpholine 1.5-2.5%
Soy or dairy protein 0-4%

Produce coatings at this stage taste terrible, and are not fit even for an animal.

The coating is sprayed onto fruits or vegetables using a method called wet casting. After the coatings have been sprayed onto produce, they go through a drying tunnel and the alcohol and water evaporate. The drying tunnel operates at temperatures considerably less than yad soledes bo, and is typically 105 degrees Fahrenheit.18

What is left on the fruit or vegetable after drying is the base and additives, minus the water and alcohol. The significance of this fact is that whatever percentage a given additive is in the original solution, that figure is approximately four to five times that percentage of the actual coating on the fruit. In other words, if a given ingredient would be only 1% of the coating in the original solution, it would constitute 5% of the coating that is actually found on the fruit.

After drying, the range of ingredient proportions in a coating, based on the numbers cited in Table I, is:


Ingredient Proportion
Carnauba wax/shellac 75-80%
Fatty acids (mostly oleic acid) 11-14%
Morpholine Difficult to estimate since it gradually evaporates
Stearic acid Less than 1%
Soy or dairy protein 0-25%

A dried shellac or carnauba wax based coating at this stage tastes mildly unpleasant. The presence of produce coatings on fresh fruits or vegetables is so minimal that any off-taste in the actual coating is undetectable.

Based on all of the above, if in fact the oleic acid is from a non-kosher source, would such a coating be acceptable? There are various reasons to be lenient. One of them is that, according to some poskim, in a non-food product such as toothpaste, a non-kosher ingredient such as animal-derived glycerin would be batel b’rov. Here too carnauba wax and shellac, the standard bases for produce coatings, are considered halachically to be a non-food product. Therefore any possible non-kosher additive would be, like the case of the toothpaste, batel b’rov.19

A dairy protein would similarly be batel b’rov.

Ideally, it would be best to use kosher certified coatings on fresh produce. However, since the kosher consumer and kosher agencies have no practical way to determine what coating was used, one should consult his or her posek.

[1] The labeling law can be found in the Code of Federal Register (CFR) 101, 21 (22)..
[2] Advertisements or other literature that promote a product is not credible.
[3] The usefulness of coatings is not limited to fresh produce. According to Dr. J.H. Han of the University of Manitoba whey-protein (dairy) based coatings may be used on pizza between the cheese and the crust to keep the crust crispy, and in fruit pies to keep the fruit from softening the crust. Enrobing pecans in butter pecan ice cream and separating caramel from chocolate in candy bars are other possible applications for coatings.
[4] Minchas Yitzchak 10:65 also discusses shellac and Rav Shlomo Shmuelevitz, Halichas ha Sadeh 109 raises possible objections to the acceptability of shellac. A detailed discussion of this matter is beyond the scope of this article.
[5] Sometimes, stearates, which can be animal-derived, may be used at a late stage of the processing. Carnauba wax, however, is not considered a food item. Therefore, some poskim argue that the presence of a stearate would be batel b’rov, nullified in the majority, as explained at the end of this article.
[6] A sucrose ester is the result of a reaction between a sucrose molecule and several fatty acids. Those fatty acids can be either vegetable or tallow (neveilah) derived. However, many manufacturers, particularly in Europe and England, are avoiding animal-based ingredients because of BSE (a transmittable cattle disease).
[7] Levush, Ateres Zahav 81.,8.
[8] “New Edible Coatings May Protect Fresh Food” USDA Office of Information, July, 1989. “A new, casein-derived coating might meet… the requirements of an ideal coating…” pg. 1
[9] “Application of Wheat Gluten Edible Films to Strawberries”, Grosso et al., poster session at Institute of Food Technologists Conference, New Orleans, 2001
[10] “Edible Coating” course sheet from Agridata, “Processing of Raw Materials for Non-Food Materials” See:
[11] “New Coating Formulations for the Conservation of Tropical Fruits” Dr. Elizabeth Baldwin, USDA/ARS Citrus & Subtropical Products Laboratory, Winter Haven, FL
[12] Dr. Bob Hagenmaier, USDA, said that a triglyceride emulsion research is being conducted at an ARS (Agricultural Research Service) lab, which is funded by the USDA.
[13] Coatings derived primarily from animal sources are legally approved but are not known to exist. Supermarket signs that declare that produce is not being coated with animal-based produce coatings operate with the presumption that no companies actually are using animal-based coatings. But it is legal to market animal-based coatings.
[14] An emulsifier is an ingredient that helps ingredients that would otherwise separate remain mixed in solution. Oil and water mixed together would, eventually, separate if not for the presence of an emulsifier to maintain them as a mixture. One way an emulsifier does that is by keeping the oil molecules far apart from each other so that they do not coalesce.
[15] One recent financial market report (ICISLOR Market Report, Fall, 2001, pg. 2) emphasized the same point, stating “Industry provided inventory levels are suspected – and generally accepted – as slanted toward tallow goods” as opposed to vegetable based goods. The topic of the report is tallow-derived glycerine (the other major component of fats and oils) but tallow-derived fatty acids may also be included in this broad assessment. Sometimes tallow-derived ingredients have to undergo special costly testing called chick-edema testing to guarantee that a food grade tallow-derivative is safe. But even with that additional cost, according to an oleochemical broker the cost of tallow would be less than vegetable.
[16] Ethanol can come from wheat (chametz) and, when produced abroad, often is. Domestic ethanol is almost always corn-based. Ethanol ultimately evaporates from a coating in the course of production. Although it may become absorbed into the other ingredients through kevishah, prolonged immersion, the corn-based ethanol would be batel b’rov. (Mishneh Berurah 453:9).
[17] The information in Tables I and II was provided by Dr. Bob Hagenmaier, Research Scientist, USDA.
[18] Minchas Yitzchok 10:66 discusses a case in which a possibly non-kosher coating was applied to a fruit which traveled through a drying tunnel which may or may not have been yad soledes bo (early drying tunnels were less efficient at drying coated fruits and therefore may have reached 120 degrees or more inside the drying tunnel). Minchas Yitzchok concludes that if the drying tunnel is not yad soledes bo then shifshuf gadol, rubbing well, is sufficient to remove the chashash issur, a kashrus concern, (if a drying tunnel is yad soledes bo then k’dei netilah, removing a thin layer, is necessary). However, according to the Produce Marketing Association produce coatings cannot come off simply by rubbing and recommends purchasing uncoated fruit, or simply peeling fruit, for those who want to avoid eating a coating.
[19] The following considerations would address the permissibility of a possibly non-kosher emulsifier, oleic acid:
a) Rav Tzvi Pesach Frank zt”l holds that an emulsifier is a davar hama’amid – without it a solution would lose its essential property of being uniform, and therefore it is not batel. However, the emulsifier is only operating as such in a preliminary stage of coating production—when the carnauba wax/shellac is in water. After the coating has dried, the water/alcohol portion evaporates and the emulsifier, which was previously keeping the water/alcohol uniform with the carnauba/shellac, no longer operates as an emulsifier per se. Therefore, the stringency of Rav Tzvi Pesach Frank, zt”l would not apply.
b) The action of the oleic acid helps to maintain something called a micro-emulsion. One distinction between a micro-emulsion and a standard emulsion is that the wax/oil molecules are so small and so disparate – as a result of the emulsifier — that light rays can actually penetrate the coating material. As a result, the produce coatings are clear. A standard emulsion (such as milk) is opaque. One can question whether the achievement of the oleic acid in creating a clear material meant that the oleic acid’s presence is impossible to deny and therefore not batel — a concept known as p’ulasa nickeres. However, since its effect was to make something invisible rather than visible, the idea that its action is nickeres – recognized — is not applicable.