I am interested in using a food grade tin (such as this) to store small amounts of food, in particular for storing summer sausage or cheese for short periods of time (1-2 days). What are the food safety concerns (if any) for this? My searches online seemed to concentrate on reusing industrial canned food containers (verdict: not recommended), and I'm not sure if this type of container warrants different treatment.
1From a materials science point of view -- the main issue is if it's coated or solid; if it's coated, then too much scouring when cleaning can chip the coating exposing the core.– JoeJul 8, 2015 at 17:31
Would there be a way to tell one from the other visually? The home site for those tins (here: specialtybottle.com/screwtoptincontainersmi.aspx) says they're food grade, but offers no additional information.– cryptic_starJul 8, 2015 at 17:36
Sometimes there are tooling marks, which would show that it's solid (I don't see any). With it being matte (non-shiny), it suggests it's coated but there could've also been some sort of etching done afterwards to hide tool marks.– JoeJul 8, 2015 at 17:45
1Thank you! If you would like to add a general version of your original comment as an answer, I think that it's an acceptable response to my question.– cryptic_starJul 8, 2015 at 17:49
The problem is that many 'food grade' tins are coated, and not solid. As such, cleaning them can end up flaking off the coating that's been applied, making them reactive.
Unless you're dealing with antique materials, I suspect that the majority of 'tins' are going to be either coated steel, or stainless steel.
Although I mentioned looking for tooling marks, and if it's matte or shiny, an easier test might be to use a magnet -- if the magnet sticks, they're most likely steel, and thus prone to rusting. Even if they're coated, if you put something moist in there, it can seep into any cracks it finds, leach at the metal, and then ruin your food. I had this happen with some Pecan Whiskey Cakes that I had put up, as they need to soak for a couple of months ... I now understand why my aunt wraps hers in (alcohol soaked) cloth, then a plastic bag, then whatever she's going to store it in.
You could probably do the same thing as you're only dealing with a few days -- wrap it in plastic, then put them in the tin.
It's possible that some (non-stainless) steel containers might have a more durable coating ... but unless it's specifically sold as being re-usable (or as wombar mentioned, for the industrial/institutional market), it's likely made to keep the costs down and not intended for re-use.
You should also avoid acidic or salty items, as they're known to pit stainless steels, especially when there's moisture and/or poor ventilation.
Different types of tins are intended for storing different types of foods (dry crackers are very different from cheeses that contain some moisture). And as mentioned previously, linings can chip when the tin is being cleaned. Food grade does not mean that they are reusable - I'd contact the source and ask them. Usually the I&I (industrial and institutional) market has sturdier packaging than home use. If the I&I is not to be reused, I'd really doubt yours is suitable, especially for moist products.
People have been storing food in tins for generations with no negative effect. I remember crackers being sold in tins when I was a kid. Have at it. You'll be fine. You may not want to store moist food in it once you start seeing rust though.