Cara Cara oranges: thinking about citrus fruit coatings
[and close-up images of their Sunkist-brand poly bag design]

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Clip-on phone camera microscope view of a section of orange-skin-pattern from the design printed on the bag of Cara Cara oranges.
Clip-on phone camera microscope view of a section of orange-skin-pattern from the design printed on the bag of Cara Cara oranges

Last month, we tried a type of orange that was new to us: Cara Cara. The origin of this orange cultivar is a fascinating story and the way that citrus farming works in general is quite intriguing as well, but neither topic is one I’ll tackle today.

Our Cara Cara oranges were Sunkist-branded and the printing on their polyethylene bag made some claims:

LOW ACIDITY
PINK INSIDE
EXTREMELY SWEET

The first two promises, regarding the acidity and color of the flesh, were borne out. I don’t recall them being especially sweet, however.

Here’s a photo of the front of the bag and a close-up of one of the parts of the design printed thereon that incorporated a copy of the sort of sticker that was stuck onto each orange:

Now-empty bag of Sunkist-brand Cara Cara oranges (LEFT) and a close-up on an unusual (to me) design for a bar code incorporated into the stickers pressed onto the oranges (RIGHT).
Now-empty bag of Sunkist-brand Cara Cara oranges (LEFT) and a close-up on a section that featured an image of the sort of sticker pressed onto the oranges (RIGHT).

There was also some fine print on the bag about the wax coating(s) applied to the oranges:

COATED WITH FOOD-GRADE VEGETABLE WAX, BEESWAX, LAC RESIN, AND/OR WOOD RESIN TO MAINTAIN FRESHNESS.

Food-grade vegetable wax? I suppose that might be alright, though the alert contemporary consumer may be cognizant of the murky origins of those industrial products sold under the term of art vegetable oil and the health risks associated with their consumption and be wary of seemingly related vegetable waxes. Beeswax sounds natural and safe, though a pessimist (realist) may wonder how far the definition of beeswax might have been stretched nowadays and how much processing and modification beeswax may undergo in big-agriculture industrial processes.

Lac resin stands out as something unusual and a quick look-see online informs us that Lac is the resinous secretion of a number of species of lac insects, of which the most commonly cultivated is Kerria lacca.. The same bug secretions, processed slightly differently perhaps, become shellac.

The last coating, wood resin, is another queer-sounding material (in the context of coatings for citrus fruit at any rate) but a very illuminating technical evaluation report from ten years ago (Wood Rosin: Handling/Processing [PDF]) includes this line early on: Wood rosin is currently erroneously listed at 205.605(a) as ‘wood resin.’ Wood resin is the raw material exuded by coniferous trees before it undergoes distillation and refinement steps as described in this report. So the wood resin that may have been (we can’t know for sure thanks to the and/or wording in the text on the bag) applied to these oranges was hopefully wood rosin produced from processing the raw wood resin extracted from the stumps of Longleaf and Slash pine trees.

That paper was compiled by OMRI for the USDA National Organic Program and is hosted on a subdomain of usda.gov but it’s worth noting that OMRI, the Organic Materials Review Institute, is a 501(c)(3) nonprofit based in Eugene, Oregon and is not a government agency.

The OMRI report mentions that wood rosin of the sort approved for use in fruit coatings is produced only by a company called Pinova Solutions headquartered in New Brunswick, Georgia and Pinova is cited multiple times in that document but… Pinova’s facility seems to no longer be in operation, as of 2024.

Pinova had been owned by a company called Symrise (whose current homepage title tag reads: Symrise I Food & Beverage I Scent & Care I Fragrance – Symrise) but, in 2016, Symrise sold Pinova to a private, family-owned French company called DRT (DRT stands for Dérivés Résiniques et Terpéniques), which (as of 2016) owned or co-owned pine-resin-processing facilities in France, China, and India. A very short (two-sentence) 2023 article in the local New Brunswick, Georgia newspaper says, Pinova Solutions is closing its doors permanently, a statement from the company said Wednesday. So the wood resin (wood rosin, hopefully) which may or may not have been slathered onto those oranges could have come from pine tree stumps’ sap processed in France, China, and/or India.

Some searching around suggests that a piece of citrus fruit destined for sale in a supermarket is often coated twice, first with a waxy layer to prevent moisture loss (drying out of the flesh that would affect the weight of a piece of fruit and presumably make it less juicy) and a second outer layer to make it shiny to attract consumers and the shininess is measured using a reflectometer. Flavor is a very distant secondary consideration. To get an idea of what’s going on here, you could skim Layered Coatings to Control Weight Loss and Preserve Gloss of Citrus Fruit (a late-1993 paper by Robert D. Hagenmaier and Robert Baker, published in April 1995 in the journal HortScience) and/or any one of a number of other similar papers that you can turn up by searching for information on citrus fruit coatings using some of the aforementioned ingredient names.

Do any of these substances or their degradation byproducts or, for example, solvents used during the extraction or processing steps of their manufacture ever diffuse inwards into the flesh of the fruit? Hopefully not. Or, more realistically, hopefully not to a level that would have negative effects on one’s health. If anyone has ever delved into this area of inquiry, they don’t appear to have published the results of their studies. There has been work done on pesticide penetration of fruits and vegetables and some of that has reached the mass media (e.g. Do Pesticides Get Into the Flesh of Fruits and Vegetables? [NYT: November 10, 2017], archive.is version) but the issue of “wax” coatings applied to produce as a source of contamination doesn’t seem to have gotten much attention. Moving right along…

Packaging technology and labeling always has the potential to be interesting and, as I was about to stuff this empty bag into the trash, I noticed a detail that must have been present on every one of the little stickers pressed onto each of the oranges but which had escaped me every time I’d peeled one of them: an odd-looking, three-row ‘wasp-waisted’ barcode. The design of the per-fruit sticker containing that barcode is reproduced on the bag multiple times and if it didn’t jump out at you earlier, you can scroll up the page now to see a combined photo of the front of the bag and a zoomed-in pic of a part of the printed design that features one of these stickers.

A March 8, 2010 article by Carl Collen (Sunkist launches new barcode label), posted on fruitnet.com, presumably a trade publication/website, describes Sunkist’s rollout of this sort of label and states, in part:

The new GS1 DataBar label includes embedded information such as a registered Sunkist identification number, the citrus variety, size code and country of origin.

The specific type of GS1 DataBar Coupon on these Cara Cara oranges seems to be the GS1 DataBar Stacked Omnidirectional variant. I didn’t expect to learn very much from scanning and decoding it but went and did it anyway. Not all barcode-decoder smartphone apps can process GS1 barcodes, but I installed GS1 Barcode Scanner by Alexandros Chaniotis from Google’s Android appstore (Google Play) and it worked. The value encoded was 00605049031109:

Phone screen captures of Alexandros Chaniotis's GS1 Barcode Scanner app, including the decoded value of the barcode on the printed-on sticker on the polyethylene Sunkist Cara Cara oranges bag.
Phone screen captures of Alexandros Chaniotis’s GS1 Barcode Scanner app, including the decoded value of the barcode on the printed-on sticker on the polyethylene Sunkist Cara Cara oranges bag.

Viewed through a clip-on “microscope” for mobile phone cameras, the design of the bag looks very interesting indeed. I know virtually nothing about the printing processes used but to my layperson’s eye it looks as though something like Ben Day dot technique has been used.

The remainder of this post consists of images of parts of the bag, many including bits of the GS1 DataBar Stacked Omnidirectional barcode, taken using a mobile phone camera through the clip-on magnifier thingamajig:

Another clip-on microscope picture. This one is of the center of the barcode, at its leftmost edge.
Another clip-on microscope picture. This one is of the center of the barcode, at its leftmost edge.
Another clip-on microscope picture. This one is of a part of the center of the barcode.
Another clip-on microscope picture. This one is of a part of the center of the barcode.
Another clip-on microscope picture. This one is of a part of the center of the barcode.
Another clip-on microscope picture. This one is of a part of the center of the barcode.
Another clip-on microscope picture. This one is of the letters 'SUN' in 'SUNKIST'.
Another clip-on microscope picture. This one is of the letters ‘SUN’ in ‘SUNKIST’.
Another clip-on microscope picture. This one is of a part of the barcode again.
Another clip-on microscope picture. This one is of a part of the barcode again.
Another clip-on microscope picture. This one is of a part of the barcode again.
Another clip-on microscope picture. This one is of a part of the barcode again.
Another clip-on microscope picture. This one is of the oranges' place of origin and the bottom edge of the orange cultivar's name ('CARA CARA').
Another clip-on microscope picture. This one is of the oranges’ place of origin and the bottom edge of the orange cultivar’s name (‘CARA CARA’).