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The majority of food additives are safe, but there are exceptions, and every now and then, one is removed from the market. The fact that some dyes, such as Red # 2, are banned in the United States but allowed in Canada demonstrates that, in some cases, "safety" is open to interpretation. Red # 40, which was used in the United States to replace Red # 2 and is allowed in Canada, is banned in Austria, Belgium, Denmark, France, Germany, Norway, Sweden, and Switzerland.
Controversial actions by activist groups have fueled worries about complete groups of additives in some instances. The case of artificial sweeteners is a prime example.
Accidental additives
Some 10,000 substances make their way into food during=growing, processing, and packaging; some of these accidental additives can pose more of a health threat than preservatives and other direct additives. Some-foods, for example, contain traces of pesticides sprayed on crops or applied to the soil. Environmental pollutants in foods, such as PCBs, mercury, and lead, are harmful when ingested in large quantities.
Sometimes allergic reactions that are blamed on foods or intentional additives are actually triggered by an unintended one. For example, a per-son who has never had a food allergy may inexplicably develop a rash after drinking milk. Allergists have traced the symptoms in some cases to penicillin used to treat mastitis in cows. The resulting small amounts of penicillin in the milk would not be harmful for most people, only to those who are allergic to the drug.