Jarred pesto isn’t a common source of botulism but in 2014 it was the source of a botulism outbreak that sickened two people. The outbreak marked the only time pesto was documented as a source of a botulism outbreak in the U.S. and the first time in 15 years that it was the source of a botulism outbreak in other countries.
The pesto had been purchased from a farm stand in San Clemente, California. Lab testing found botulinum toxin in leftovers of pasta with pesto. During an investigation of the company’s facility, health officials found improper acidification and pressurization practices and that the company lacked the proper license to sell canned products.
Botulism can cause life-threatening illness or death. Food that is contaminated with botulism may not smell or look spoiled. Symptoms of botulism include general weakness, dizziness, double-vision and trouble with speaking or swallowing. Difficulty in breathing, muscle weakness or abdominal swelling may also occur. Anyone with these symptoms should see a doctor immediately.