The Pittsburgh Area Food Bank is recalling canned oranges due to leakage. While the product is within the stated shelf-life, it can be noted that the manufacturer has stated a three year shelf-life, which may be an error on the manufacturer's part. Acid foods in cans do not last long, and normally, the shelf-life is two years. The reason is that the acid will react with the can lining, and over time, it will get through to the steel base and rust through. This is especially the case with tin-lined cans (additionally, if tin lined, tin concentrations will increase). As cans begin to deteriorate, you will initially see a hydrogen swell...hydrogen gas is released as the acid reacts with the can. As the can swells, the ends will pop up. But once the acid eats through the can leading to a pinhole, the pressure will be release and the can may look normal.
Food banks will normally distribute product past the state shelf-life. For low acid canned foods, one to two years is normal. In many cases, those types of foods will last even longer (although the product will break down over time...unlike fine wines, canned foods do not get better over the years). But for acid foods, 6 months should be a limit past the life of the can. And in the example here, the cans did not even make it that long.
Other potential issues that could have resulted in leakage: A bad seam - a double seam (the seam that holds the lid to the body) can be out of specification leading to too little of overlap and thus a weak seal. Damage to the double seam - cuts into the double seam or dents to the double seam can also result in leakage. Headspace evacuation - If the air in the headspace was not properly evacuated with steam, residual oxygen could hasten can deterioration.
FDA Recall Notice
http://www.fda.gov/Safety/Recalls/ucm493605.htm
Food Bank Recalls Canned Mandarin Oranges Due to Possible Health Risk
For Immediate Release
March 17, 2016
