Inks and coatings were obtained from the inks industry and were analysed to identify the chemical compounds present and to estimate their concentrations. Data on formulations and applications was obtained and used to estimate the potential migration of each of the compounds, based on the level of ink application, the area potentially in direct contact with food, and a worst-case assumption of 100 per cent migration.
The use of direct contact printing inks in retail applications was assessed via industry contacts and retail outlets. The main use of direct contact inks in the UK was found to be \'open and win\' style promotions on confectionery packaging. Only one packaging sample was obtained throughout the duration of this project from a non-confectionery product, which was the use of direct contact ink on the lid of a yoghurt carton. Manufacturers of direct contact inks in the USA suggested other applications but no examples were located in retail outlets in the UK.
Seven different printed packaging materials, which had inks on the food contact surface, were obtained from industry or from retail outlets. Six were confectionery wrappers (two industrially supplied reels of wrapper intended for the confectionery market that had not been in contact with food, four obtained from retail purchases) and one was the lid of a yoghurt carton. They were analysed to determine the chemical composition of the printing inks. From the results obtained the worst-case migration potential was calculated.
Printing inks and associated coatings have traditionally been applied to the outside of food packaging. Printing can provide information about the product, including appearance, ingredients listing, nutritional content, best-by and display until dates, storage instructions, preparation instructions etc. With the fierce competition which exists in the food marketplace, manufacturers and retailers look for new ideas to ensure their products outsell those of their competitors. One commonly used tool is some form of \'promotion\'. This may be a free gift in the pack, a competition with prizes or a simple \'open and win\' promotion. For packs with a large surface area, these promotions can generally be printed on the outside of the pack. For small volume items such as confectionery bars, however, there is limited space on the pack exterior and it is becoming more common for promotions to be printed on the inside or for a printed enclosure to be placed in the pack.
The use of direct contact printing inks (inks used on the inside of food packaging in direct contact with the food) is likely to increase. The EU has not yet legislated in this area and, although the Council of Europe is compiling a resolution on printing inks, it specifically does not apply to direct contact printing inks. There is considerable evidence that chemical migration can occur from packaging materials to food. That manufacturers are now printing on the direct food contact surface raises obvious questions - what chemicals are used, could they migrate to the packaged food and, if so, are any migration levels of interest? These questions were addressed in this project.
<p>Find more about this project and other FSA food safety-related projects at the <a href="http://www.food.gov.uk/science/research/" target="_blank">Food Standards Agency Research webpage</a>.