Printing & Design Tips: DECEMBER 2006, #65

Soy Ink in Food Packaging

I was recently asked by one of my readers whether soy ink can be placed in direct contact with food (without being toxic). He was interested in printing on the inside of a box that would contain a chocolate bar. The research I did has led me to believe this is usually a bad idea.

What I learned about soy inks is that each ink is made up for a specific purpose: sheetfed work, web printing, or newspaper printing. Depending on the substrate on which the ink will be printed, the soy ink mixture usually includes some petroleum-based component. This is because soy ink dries slowly, and the petroleum-based chemistry of the ink mixture reduces the drying time. It is also toxic. (However, an ink consultant with whom I discussed this matter said that some soy-based inks are petroleum-free and contain only vegetable products. In this case, contact with food would be ok.)

In addition, ink used for printing newspapers can be petroleum-free. In contrast to products printed on coated or uncoated stock other than newsprint, newspaper ink dries primarily through absorption. The ink soaks into the fibers of the newsprint. (Ink printed on coated stock, in contrast, dries sitting up on the paper’s surface.) Therefore, newspapers can be printed with a soy ink mixture that has little or no petroleum-based content. It can therefore be non-toxic (if it is completely petroleum-free).

Since newsprint is not ordinarily a stiff enough substrate for printing a candy-bar box or wrapper, a better option would be to use specialty inks created for packaging, such as UV inks. These inks, which could be used both inside and outside of a box (and be printed on either coated or uncoated stock), cure (or dry) when exposed to UV light. They are chemical-resistant and non-toxic. In addition, they contain no solvents, and they are scuff resistant. However, the FDA still requires—for blanket safety—that there be a functional barrier between the printed image and the food. In this case, it can be the opposite side of the printed sheet. (The ink consultant with whom I spoke, however, was hesitant about using UV inks with any food packaging.)

In my research I came upon another item of note as well: The customary printing process used for food packaging is flexography. Flexography uses rubber plates with a raised image area to print quick-drying inks directly on foil, plastic wrap, and other packaging material. This process is often used for milk cartons, other food cartons, and candy wrappers. However, the inks used in this process can in fact still be toxic, and in this case the functional barrier required by the FDA certainly would be essential. Usually there is an additional paper, foil, or plastic barrier. For example, you will notice that there is often printing inside a cereal box, but the cereal itself is enclosed in a plastic bag.

The conclusion I have drawn from all of this disparate and somewhat conflicting information is that only pure soy ink can be in contact with food. (Apparently the printed cards in the bags within the cereal box—found amidst the actual cereal—are printed with pure soy ink.) The FDA apparently allows this. However, anything less than pure soy ink absolutely requires a functional barrier between the ink and the food.

Printers' Samples: What Should You Look For?

I recently received a sample packet from an offset printer that knocked my socks off. I asked myself why.

The packet included a wide array of printed materials, from booklets to stationery. Some samples were printed in process inks, some in PMS inks. The packet included items printed with metallic inks, die-cut samples, and samples of heavy solids (areas of the printed sheet completely coated with a thick layer of ink). I noticed interesting folds, done precisely and without error. In short, I could see a variety of difficult printing challenges executed with skill.

Would I send this printer a job? Probably, because the representative who sent me these pieces had excellent taste and paid close attention to detail. It would be comforting to know that I would have a knowledgeable advocate in the printing plant should I send this company a print job. I would also be making a decision to buy printing from this supplier based on the variety of the samples. I can see by looking at the collection of printed pieces that the printer does more than one kind of work very well, and I can see that the work is all "high-end." If the printer can do this difficult work well, he can probably do simple two-color brochures well, too.

In short, what should you look for in evaluating printing samples?

Look for quality. If there are problems like crooked folds, hickies, or offsetting ink, the pressroom has technical problems, and the sales rep hasn't noticed the flaws in the samples. This is a red flag, and this printer should be avoided.

Look for compatibility. Did your printer send samples that match the jobs you produce? If the printer does high-end work (as noted above), their simpler work like newsletters might be stellar, but it might also be expensive. You don't need to use a hammer to kill an ant. On the other hand, if the printer only sends you newsletter samples, I would hesitate to ask him to produce a complex, die-cut kit folder.

Your printer isn't just selling you printing. He is solving your marketing problem, giving you one less thing to worry about. If he listens to you and understands what you need and, more specifically, what your printed product will be expected to achieve (taking into account your audience), he can help you. If not, you're both wasting your time.

[Steven Waxman is a printing consultant. He teaches corporations how to save money buying printing, brokers printing services, and teaches prepress techniques. Steven has been in the printing industry for thirty-three years working as a writer, editor, print buyer, photographer, graphic designer, art director, and production manager.]