Adulteration means adding impurities or inferior substances to a product in order to deceive or reduce its quality. It's like mixing or contaminating something good with something bad. Full definition
There is little of art in his vision of good cooking; except for his just complaints about adulteration of food with harmful substances, he often sounds simply like an old grump complaining about the menu. (firstthings.com)
Moreover, when human milk becomes a tradable commodity, there are also risks of adulteration with cow's milk to enhance profit. (babymilkaction.org)
By way of example, he has highlighted how six common food products, including infant formula, guacamole and chorizo, could be at risk of food adulteration. (theguardian.com)