Herbs, Spices, and Food Poisoning

It has been suggested that people first began to use herbs and spices, particularly in tropical countries, because their defensive chemicals help control the microbes that cause food poisoning, and thus made food safer to eat. While some—garlic, cinnamon, cloves, oregano, thyme—are fairly effective at killing important disease microbes, most are not. And many, especially black pepper and others that take several days to dry in tropical climates, carry millions of microbes in every pinch, sometimes including E. coli and disease-causing species of Salmonella, Bacillus, and Aspergillus. This is why spices are often fumigated with various chemicals (ethylene or propylene oxide in the United States) or steamed. About 10% of imported spices are irradiated to eradicate microbes.