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.]