In 1974, scientists opened canned food recovered from the steamboat Bertrand, which sank in 1865, and found no microbial growth. This episode tells the accidental history of canning, from Napoleon’s 12,000 franc prize and Nicolas Appert’s glass jars to heavy tin-coated iron cans.

We explore the Franklin expedition, why the can opener came decades after the can, how World War I rations boosted morale, the science of botulism and pressure canning, the engineering of the double seam, and what canned food means for nutrition and the economy today.

• How Nicolas Appert preserved food without understanding microbes, later explained by Louis Pasteur
• Why newer research points to malnutrition rather than lead poisoning in the Franklin expedition
• How French and Italian armies used canned cuisine like coq au vin and ravioli to lift morale
• The pH 4.6 threshold for botulism, pressure canning, and the five-layer double seam
• Canned tomatoes and lycopene, rinsing to cut sodium, BPA-free linings, and recession-era cocooning