How to Avoid Ink Migration with Food Packagin

For those in the food packaging industry, properly encoding packages is a must. Depending on the items being packaged, your product line may need to be encoded with a combination of tracking codes, expiration dates, lot codes, and/or barcodes. In certain cases, if these codes are not properly placed, the product will be in violation of USDA standards and companies may face expensive, time-consuming recalls. In other instances, even when the correct codes are placed on packaging, another potential danger exists: ink migration. 

Ink migration refers to ink particles that seep from the surface that they’re printed on into or onto adjacent/neighboring surfaces. The issue is when this gets into the food itself. Expectedly, this contact can cause a myriad of health concerns as well as put products in violation of federal regulations. 

Fortunately, there are steps that you can take to prevent this from occurring in your operation. This article will explore the types of ink migration that affect food packaging, why they occur, and how you can fortify your operation against this lurking threat.

The Different Types of Ink Migration

With food packaging, there are four different types of ink migration to be wary of:

  1. Penetration/Diffusion Migration 

The ink transfers from the printed spot on the packaging onto the reverse side. This occurs as a result of the ink’s chemical properties and particle size. Small, mobile ink particles freely pass through the packaging or are drawn through by the food contents on the other side. 

  1. Set-Off Migration 

The ink migrates from one printed package or surface and onto another package or surface that is stacked upon it or within the same reel. Typically, this form of ink migration cannot be seen. An example of this would be yogurt containers being printed on and then stacked prior to being filled. 

This migration form often affects labels, lids, packaging film, and cups, as they're stored in-close contact or placed in reels.

  1. Vapor Phase Migration 

This migration type occurs when certain foods are heated while still in their original packaging (e.g., a microwaveable meal that remains sealed during cooking). As the packaging becomes hotter, the ink compounds can change, permeate through the substrate, and end up in the food. In addition to temperature, humidity and pressure can also drive this form of migration. 

  1. Condensation Extraction 

This form of ink migration is similar to vapor phase migration and occurs when inks migrate via condensation during cooking or sterilization.

How to Protect Food Packaging from Ink Migration

Just as there is a huge variety of inks in use, there are a number of factors that cause migration to occur. To fortify yourself against these risks, you need to consider:

What Material Are You Packaging Food With?

Depending on which materials you are using to package your food, you could be in need of selecting a specialized ink to prevent migration. If you are using containers that act as absolute barriers (e.g., glass bottles, metal cans, etc.), this won’t be a concern. However, for containers made of plastic or paper, the threat of migration needs to be accounted for. 

To make these at-risk containers functional barriers, you need to use an ink type specifically formulated to resist migration

What Ink Are You Using to Encode Your Products?

Absolute barriers like glass bottles naturally resist multiple forms of ink migration, so particular ink types aren't as much of a concern compared to paper and plastic packages. For more migration-susceptible materials, you will typically need to look into water-based ink formulations, as these ink types are typically safest around food. 

Accordingly, food manufacturers will want to use a printer that is compatible with these formulas:

  • Continuous inkjet (CIJ) printers, such as the DuraCode, use a combination of ink and solvent for high-speed encoding. Since this printer uses solvent-based inks, you will want to use it in situations where ink migration is not a concern. 
  • Certain thermal inkjet (TIJ) printers, such as the Anser U2 Pro-S, also have the ability to use solvent-based ink cartridges, while most thermal models will tend to use water-based inks (which are also resistant to migration). 

Of course, given the vast difference in how certain inks will react to specific substrates, temperature levels, moisture, and ventilation, we highly recommend consulting with an expert before investing in equipment/inks to make sure that you have found a safe combination for your operation. 

Be Proactive Against Ink Migration with Food Packaging

To avoid possible product recalls and FDA violations, it’s essential that you protect your food packaging operation from the real danger of ink migration. Fortunately, our team of experts and ink chemists have been developing ink technologies for over 25 years, and we can help you determine the best formulation for your product line. Whether you need a custom ink solution or guidance on what hardware will best suit your operation, we are here to help you. 

For more information on the effects of ink migration with food packaging and guidance on how to prevent migration from occurring in the first place, contact InkJet, Inc. online or by phone at (800) 280-3245.