Think of the geographic origins of all your favorite spicy food cultures. What do these places have in common? Warm tropical breezes? Afternoon siestas? As little clothing as culturally acceptable? Sure. But also PATHOGEN LOAD.
If you think about the origins of spicy foods – delicious cuisines such as Thai, South Indian, Mexican – they all tend to be warm, tropical, and located nearer the equator. In other words, not your Canadas, your Finlands, or your Germanys. And why might that be?
Spices (aromatic plant materials, not used primarily for nutrition) are used differently by different cultures, and there appears to be a geographic cline. Sherman and Hash (2001) scoured more than a 100 traditional cookbooks of 36 countries. What they found was this: The higher the mean annual temperature of the place, the more spices they used. The warmer the place, the more recipes containing more than one spice, the higher the average number of spices used per recipe, and the more likely to include spices with potent antibacterial capabilities. And the warmer a place is the greater the diversity and growth rates of food-borne pathogens. This pattern is evident even when looking at variation of spice usage within a country, indicating that availability of spice plants was not a driving factor. Further, they found that recipes involving meats, which spoil more rapidly, contained more spices than vegetable-only recipes.
The use of spices to inhibit pathogen growth would have been especially important before the widespread use of refrigeration. The complexity and heat of that vindaloo all begins to make sense now, doesn’t it?
Sherman, P., & Hash, G. (2001). Why vegetable recipes are not very spicy Evolution and Human Behavior, 22 (3), 147-163 DOI: 10.1016/S1090-5138(00)00068-4