In the quantities found in food-grade tinplate, tin is considered non-toxic. It's chemically stable, doesn't readily dissolve into food, and has been used in food packaging for over 200 years. The World Health Organization has reviewed tin in food and set acceptable daily intake levels — which normal food-tin usage sits well under.

This is very different from, say, lead — which is genuinely toxic and was historically used in food packaging before being banned. Tin replaced lead in many applications precisely because it's safer.

Minimally — and usually below levels of concern. Tin can dissolve slightly when in contact with highly acidic foods over long periods. This is why canned tomatoes, canned citrus juice, and other high-acid products often have an additional lacquer coating on the inside of the can — to further reduce any tin migration.

For dry foods — biscuits, cookies, tea, coffee, spices, candy — this isn't a concern at all. The tin surface is essentially inert against dry goods. A biscuit tin, tea tin, cookie tin, coffee tin, or spice tin used for dry food storage doesn't have the conditions that cause tin migration in the first place.

Quality food-grade tinplate has an interior coating — sometimes called a lacquer or enamel lining — that creates an additional barrier between the metal and the food. This coating needs to be food-safe, meaning it's certified not to react with food, transfer flavor, or release harmful compounds under normal use.

At Longteng, every tin we produce for food use — from food-safe tin containers to airtight metal food storage tins, round cookie tins with lids, and rectangular biscuit tins — uses certified food-grade tinplate with compliant interior coatings. The documentation is available.

Yes — for most dry foods. Biscuits, cookies, shortbread, crackers, tea leaves, coffee beans, chocolate, candy, popcorn, spices, nuts — all of these can sit directly in a food-grade tin without any additional liner.

Where you'd want to use a liner: if you're storing something very acidic or high-moisture for extended periods. For a tin box for homemade cookies or a metal tin for loose leaf tea, you don't need one.

For most dry food applications — yes, in several meaningful ways. Metal doesn't absorb odors, so a tin that previously held coffee doesn't make your biscuits taste like coffee. Metal blocks light completely, which slows the breakdown of fats and aromatics. And metal doesn't degrade over time the way plastic does — there's no concern about microplastics or plastic compounds migrating into food.

The airtight metal tin for food storage has a real functional advantage over plastic for products like tea, coffee, and biscuits where freshness and flavor matter.