Pull the rubber seal out of your shaker lid and run a fingernail along the groove: it’s the test food-safety inspectors do first
Food safety inspectors use a simple trick to spot contamination: they pry back rubber seals on kitchen equipment to reveal what’s hiding underneath. Your gym shaker bottle likely harbors the same problem—and 90% of used bottles test positive for harmful bacteria including E. coli and Staphylococcus aureus.