A 21.7-ounce box of Apple Jacks costs around $3.44 at Walmart. But if your kids’ breakfast cereal smells or tastes odd in the morning, who cares what you paid for it? Imagine taking 28 million boxes of Apple Jacks, Corn Pops, Froot Loops, and Honey Smacks off of shelves nationwide as Kellogg did...
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Like many ecological, “green” solutions, low-migration inks do cost more than conventional inks. “Some cost only about five percent more,” said Bean, but others can be double the cost. “UV-curing products are expensive because the photoinitiators are specially made at low volumes,” he explained. “Using bigger molecules drives up the energy costs because you have to use more of them.” Ink manufacturers continue to push, “taking costs out,” he noted, and coming up with economical solutions. “The barrier coating market has been around for a while, but a new twist is developing barrier products for recycled paper board to prevent the migration of mineral oil.
“No-migration inks are coming,” Bean predicted. “Analytical techniques are too good today – they can identify a single atom.” The FDA regulates parts per billion (ppb) – even parts per trillion (ppt) – for poisons or toxicological hazards, Bean pointed out. “One ppb is the equivalent of one drop of water in a 10,000-gallon swimming pool.”
Organoleptic properties are the aspects of food or other substances as experienced by the senses. Organoleptic tests are conducted to determine if package materials and components can transfer tastes and odors to the food in which they are packaged. This is usually done by human tasters. Precise analytical testing is not inexpensive, Bean noted, “but it’s cheaper than lining up 12 [taste] experts.”
“Low Migration Inks in Packaging,” a guide to help food package providers deal with myriad of challenges, is available from INX International. The publication summarizes the latest, most relevant regulations and standards—including FDA (U.S. Food and Drug Administration) requirements for the U.S., Canada and Europe—plus packaging supply chain links and responsibilities, and practical recommendations for print-production processes. It also includes a glossary of relevant abbreviations and definitions, and a helpful tool for easily interpreting regulations, special precautions and recommendations.
In addition, a Siegwerk brochure entitled “Know How – Customer Guidance: Printing Inks for Food Packaging” contains useful information on food packaging structures and migration risks. Download it here: MyPRINTResource.com/10941207
Also, a 10-page PDF document outlining Nestle’s guidance on packaging inks is available from Xeikon and can be found here: MyPRINTResource.com/10941204
Jarek Sliwinski, technical development manager at Siegwerk/Environmental Inks, passed along information regarding printing inks for food packaging. Generally, the following parameters may increase the amount of migrants in the ink layer and/or the diffusion of migrants:
- Drying processes—drying by heat (insufficient drying may lead to increased residual solvents that might migrate)
- High printing speed—insufficient drying energy (oven temperature, drying air flow)
- High amount of ink/varnish printed on substrate—insufficient drying energy (oven temperature, drying air flow)
- Too high amounts of retarder in ink—insufficient drying energy (oven temperature, drying air flow).
- UV curing—insufficient curing may lead to unreacted monomers and increased photoinitiator amounts
- High printing speed—insufficient UV drying energy
- Loss of power of aged lamps—decrease of UV radiation dose at print surface
- High amount of ink/varnish printed on surface—insufficient drying energy (UV radiation dose at print surface)
- Addition of photoinitiator and/or acrylate monomer—insufficient drying energy (UV radiation dose at print surface).
Use Care when Printing
The higher the contact surface and the lower the volume/weight of the packed food, the more migrants may end up in the food. Even the type of food makes a difference. Some foods enhance the diffusion of migrants through the substrate/packaging material and/or mobilization of migrants present because of previous set-off. Aqueous, acidic, and/or fatty liquid foods are among the worst. Fatty solid or liquid food in aqueous liquid food, such as mozzarella cheese, also have high uptakes of migrants, as do powdery foods and pastries.
Siegwerk advises against printing additives to make press-ready inks. Also, “inappropriate printing machine cleaning agent substances may carry over to and contaminate the non-printed ink and thus the print,” the firm said. In addition, inappropriate cleaning of equipment in contact with inks, such as rollers and rubber blankets for offset, pose a risk for carry-over if the printer uses the same equipment for inks that are not intended for food packaging. The same is true for fountain solutions.