Many bottled spices purchased in stores contain preservatives, along with fillers and artificial flavor enhancers. Among these, some are irradiated with preservation in mind, meaning they have been exposed to radiation that kills bacteria.
Sodium benzoate, which is found in many commercial spices, acts as a preservative and an anti-fungal and anti-bacterial agent. It increases a spice's acidity, which prevents fungi and microbes from growing. The longer this preservative sits on the shelf, the more likely it is to form benzene, a carcinogen.
Spices that have been irradiated contain relatively low levels of natural enzymes and vitamins. They also contain carcinogenic byproducts and free radicals, which promote disease. Nearly all spices sold in the United States are sterilized, or fumigated, with chemicals banned in Europe.
To save money and avoid harmful ingredients, many people make their own cooking spice combinations at home. They start by purchasing fresh, organic spices, which are neither irradiated nor treated with pesticides. To ensure freshness, they purchase small amounts of spices at a time. Those who are too busy to make their own spices might find what they need in their local health food store. In 2015, spice brands that do not contain preservatives or other harmful ingredients include Frontier and Simply Organic.