Monosodium glutamate, the food additive, was invented in 1908 at which time the glutamate component was produced by extracting glutamate from protein — a slow and costly method.
It was reinvented in 1957 using genetically modified bacteria to produce glutamate. Following reinvention, virtually unlimited amounts of free glutamate became available, and great quantities of free glutamate, often in the ingredient called monosodium glutamate, were poured into processed foods. For the first time in history, there existed the excessive amounts of free glutamate needed to produce excitotoxicity.