A collaborative research project between the Steel and Metals Institute (SaMI) at Swansea University and Tata Steel UK highlights the exceptional performance of steel food cans and the rigorous testing protocols they undergo before reaching consumers.
This marks the 1000th joint research initiative between the two organizations. Standard food cans typically feature a steel base, coated with tin and occasionally an additional internal polymer lining. Food cans offer numerous benefits, such as extending product shelf life, preserving nutritional content, demonstrating durability, requiring no refrigeration, and being easily recyclable—key aspects of food and drink packaging.
Like all steel products, food cans must adhere to the highest standards of performance and quality. The safety of these products is paramount, particularly as they contain food.
As the industry shifts toward producing steel from recycled scrap, the same comprehensive testing applies to scrap metal. This method significantly reduces carbon emissions compared to traditional production methods utilizing raw materials like coke and iron ore, thus contributing to more sustainable food and drink packaging.
Tata Steel’s Trostre plant serves as the primary supplier of packaging steels for many household brands in the UK, covering food, home, and personal care products.
At SaMI’s facility, researchers simulate real-world conditions by putting steel products through a series of demanding tests to guarantee that they meet exacting performance standards.
Testing Procedures for Food Cans
Dr. Barrie Goode, SaMI’s Director of Industrial Research and Development, outlines the testing procedures for food cans: “We need to check how different steels interact with various foodstuffs, which may include chemical substances such as salt or vinegar. Of course, there must be no spoilage of the food, but the structure of the can must also remain robust and intact.”
“Our accelerated tests allow us to fast-forward the effects of time on the can and its contents, meaning we can simulate the results of several years in just a few weeks.”
James Edy, Coatings Researcher at Tata Steel, further explains the typical testing process: “We fill cans with food simulant solutions and then seam the lid on. A small amount of headspace is left, creating a vacuum when the can is sealed.”
“Next, we sterilize the cans at over 100°C under pressure, utilizing saturated steam, hot water, or a combination of steam and air. As pressure increases, the boiling point of water also rises, allowing for superheating without boiling. This process disinfects the contents and accelerates assessments of any reaction between the can and its contents.”
“We also conduct microscopic analyses of the cans for any degradation and potential causes. Our electron microscopes can magnify samples up to 1000 times to identify any areas of concern. Subsequently, we perform microanalysis using a technique called energy dispersive spectroscopy to identify and quantify the chemical elements in a sample.”
After testing, researchers examine several factors, including whether the lacquer film has blistered or peeled from the can, signs of corrosion at even the microscopic level, visual changes like discoloration, or compliance with stringent quality, safety, and reliability standards.
“This information is vital for our customers to assure their consumers that their products are of the highest quality. It also enables the public to trust that their food and drink packaging has undergone rigorous testing, ensuring its quality,” concludes James.
