Feeling Blue Those blue mason jars were mass produced until 1937 using sand from around Lake Michigan. It was that sand that gave the glass its blue hue.

How do you know if home canned food is bad?

Home-canned and store-bought food might be contaminated with toxin or other harmful germs if:the container is leaking, bulging, or swollen;the container looks damaged, cracked, or abnormal;the container spurts liquid or foam when opened; or.the food is discolored, moldy, or smells bad.29 Jul 2021

Can you tell if canned food has botulism?

the container is leaking, bulging, or swollen; the container looks damaged, cracked, or abnormal; the container spurts liquid or foam when opened; or. the food is discolored, moldy, or smells bad.

How do you know if you canned correctly?

If the jar is sealed correctly, it will make a ringing, high-pitched sound. Hold the jar at eye level and look across the lid. The lid should be concave (curved down slightly in the center). If center of the lid is flat or bulging, it may not be sealed.