Is that fermentation or spoilage.

How to Store Canned Tomatoes Safely

To reduce the risk of spoilage:

• Store cans in a cool, dry place
• Avoid heat and direct sunlight
• Check cans for dents, rust, or bulging before buying

The Bottom Line

A few quick bubbles right after opening canned tomatoes are usually harmless and caused by trapped gases. But if the bubbling is accompanied by foam, foul odors,continue reading …