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Just add chillies - That hot and spicy curry could be a life-saver

点击量:   时间:2017-10-19 07:02:01

By Bob Holmes HUMAN cultures developed a taste for spices as a safeguard against foodborne pathogens, according to the first comprehensive study of their use. Microbiologists have known for years that many of the chemicals that give spices their distinctive flavours also inhibit the growth of bacteria and fungi. But despite the common assumption that spices became popular because of their antimicrobial properties, rather than their taste, no one had put this theory to the test. If spices are primarily antimicrobial agents, says Paul Sherman, a behavioural ecologist at Cornell University in Ithaca, New York, their use should be more common in hotter countries, where food is more likely to spoil. “We all think we know that as you go to hotter climates, you get spicier foods. But to our surprise, that had never been quantified,” he says. Together with undergraduate Jennifer Billing, Sherman scoured cookbooks and came up with more than 4500 traditional meat-based recipes from 36 countries from Norway to Thailand. They also searched the literature for reports on the antimicrobial effects of 43 plant-derived seasonings used in the recipes. Warmer countries used a broader palette of spices in their cuisine and averaged more spices per recipe, the researchers found. Recipes from hotter countries also used seasonings with a more potent antimicrobial effect (Quarterly Review of Biology, vol 73, p 3). This seems not to be simply because more spices are available in the tropics. Warmer countries did not grow a wider range of spices than cooler ones—their cuisines merely included a greater proportion of the available seasonings. Even onion and garlic, potent antimicrobials which grow in every country studied, appear in more recipes in warm countries. Sherman agrees that we now spice our food because we like the taste. But the spices’ antimicrobial properties may have been the reason we acquired a taste for them in the first place,