Not all countries process meat in the same way. In some industrialized countries such as the United States, several products are added to meat and even more to processed meat, unlike countries such as Argentina or Australia where meat has fewer additives.

Among the substances added to meat are sodium benzoate, sodium propionate and benzoic acid, which, in some conditions, have shown to have carcinogenic potential. Nitrites and nitrates are routinely added to meat to inhibit the growth of bacteria and enhance color. When nitrites combine with some amino acids, cancer causing compounds called nitrosamines are produced.

Antibiotics are part of the diet of US livestock to make them grow faster and prevent disease outbreaks. However, antibiotics in animal feed have proven to be a significant factor for the increase in antibiotic resistance among humans. Sulfites have been widely used as preservatives in food to maintain their color and prolong shelf life. But sulfites can also trigger asthma attacks among people who are sensitive to them.

In a 2010 report, the US Department of Agriculture's Office of the Inspector General found high residues of copper, arsenic and other heavy metals and veterinary drugs in beef distributed for public consumption. In addition, traces of pesticides can also be found in some animal feeds.

Although these are just a few of the substances that can be found in regular and processed meat the obvious question is: Are meat and processed meat carcinogenic, or are the substances added to them responsible for their becoming potentially carcinogen?

These considerations point to the need for the food regulatory agencies to be stricter in their control of food quality and also the need for more exhaustive studies comparing consumption of meat and processed meats with and without harmful additives. Until the results are out, popular wisdom is still the best advice: eat everything in moderation.

The author is an international public health consultant.