“A carcinogen is any substance, radionuclide or radiation, that is an agent directly involved in the exacerbation of cancer or in the increase of its propagation.”
http://en.wikipedia.org/wiki/Carcinogen
If you can avoid eating white rice and breads that are made from white flour then it’d best. White rice and white flour’s sugars are known to promote cancer cells. Considering how they’re being grown, we can really say that white rice is toxic. Imagine since the start of planting it, the insecticides, pesticides and inorganic fertilizers have made it already a poison. Basically, foods should have been good to our body only we process them in order to please our tongues without knowing that we only fool ourselves because we are taking in poison. That is why we’d wonder why people of ancient times were able to live very long unlike people living in today’s world. There really is a big difference when it comes to life expectancy. I agree that foods that are being processed aren’t safe to eat and they are a lot. I think almost nothing would be left if you’d remove them all. So, the best thing you can do is change the way you cook the food. For instance, instead of frying the hormone-injected chickens battered with MSG-rich fry mix, you can use the organic chicken and cook it in a healthy way. If you want oil, you can always stir fry it and always add vegetables to it. Instead of using white sugar, you use the brown sugar. White sugar is known to cause constipation. For meat, avoid burning the fats because it’s the most notorious cause of cancer. In general, there are only few cancer-causing/promoting foods by nature. It’s the process that makes the foods cancer-causing/promoting. Hmm, I guess it’s time to eat healthy.
“Naturally occurring carcinogens
Though research has been more focused on pesticide residues in food there are numerous naturally occurring carcinogens in food plants. For example, tannins occur widely in plant foods and we ingest them daily in tea, coffee, and cocoa. Experiments on animals have shown that tannic acid causes liver tumors in animals, and may be linked to esophageal cancer in humans.
 Cycad plants, an important food sources in tropical regions, contain cycasin and related azoxyglycosides which when tested on rats have shown to cause liver and kidney tumors.
 Safrole, which is a liver carcinogen in rats, is found in sassafras tea, cinnamin, cocoa (trace), nutmeg, and other herbs and spices.
 Tests on mice have proved black pepper to be carcinogenic
Preservatives and coloring agents All coloring and preservatives added to food are not good for us. Artificial sweeteners (like saccharine & cyclamates) and preservatives which produce nitrosamines are known to cause bladder and stomach cancers respectively.

Tips for avoiding potential carcinogens in foods
 Look for brands of uncured, nitrate-free meat products, such as bacon in natural-food stores.
 Avoid all cakes, biscuits and cookies that list saturated fats in their ingredients.
 Wash all vegetables and fruits before consumption in clean water, or with special washing liquids available for the purpose.
 Eating organically grown vegetables and fruits would limit one’s exposure to pesticides.”

In order to know what's best to eat in order to fight cancer, see the list here: http://www.cancure.org/cancer_fighting_foods.htm

There are certain chemical in the diet which can generate super oxide free radicals that can damage DNA, rearrange the gens in our cells and leads to the development of cancers. These are then called "carcinogens"

These carcinogens are in variety of forms:

1. Acrylamides which are produces through high temperature cooking of carbohydrates, like the one in your picture, over grilling of corn.
2. Hydroperoxide, alkoxy, endoperoxides and epoxides from over heated meat, eggs, fish and pasteurized milk.
3. Polycyclic or aromatic hydrocarbons from smoked burnt, grilled or barbequed foods
4. Allylaldeyde (acrolein) butric acid, nitropyrene, benzpyrene, nitrobenzene from heated fats and oils
5. Methylglyocal and chlorogenic atrascytyosides in over roasted coffee.

The list below shows Acrylamide concentrations in common foods in FDA 2004 survey.
---quote---
*Often greater than 1000 ug/kg
Burnt barbequed meat
Grilled sweet potato crisps (chips)
Veggie chips potato snacks
Sweet Potato crisp (chips)
Roasted oat bran crackers
Veggie crisps (chips)

*Usually between 500-1000 ug/kg
French fries
Pretzels
Processed baked potatoes
Ginger snap cookies
Toasted corn
Kettle crunch potato chips
Hash browns
Pitted ripe olives
Tortillas original tostadas
Low fat bruschetta vegetable crackers
Sesame snacks
Dried soup mix

*Usually between 200-500 ug/kg
Butter flavoured popcorn
Crackers with peanut butter
Frozen potato skins (Frozen)
Corn flaked cereals
Corn chips
Cream crackers
Processed prune juice
Pepper toast
Coffee
---end of quote---

These are some tips to avoid getting carcinogens on your diet:
1. avoid heavily processed foods that contain high concentrations of additives and unhealthy fats, salts and sugar.
2. Don't reheat fats and oils
3. Don't eat superheated snacks like crisps, chips and roasted or baked bars
4. Don't eat smoked, barbecues, or burnt foods
5. Eat raw and organic foods.

Carcinogen is a substance that is capable of causing cancer to humans and animals. It could be also any substance that aggravate cancer. There are many things that can cause cancer, a substance is only considered carcinogenic if there is significant evidence of its carcinogenicity.

---quote---
The most notorious carcinogens found in our diet or environment are:-
• Acrylamides (AA) generated through high temperature cooking of carbohydrates.
• Hydroperoxide, alkoxy, endoperoxides and epoxides from heated meat, eggs, fish and pasteurized milk,
• Polycyclic or aromatic hydrocarbons from smoked, burnt, grilled or barbequed foods
• Allylaldehyde (acrolein), butyric acid, nitropyrene, benzpyrene nitrobenzene and other nitrosamines, from heated fats and oils.
• Methylglyoxal and chlorogenic atractyosides in over roasted coffee.
• Xenoestrogens - Pesticides, herbicides and fertilizers; Car pollution, Some deodorants - (the prebans and Aluminium) Polychlorinated biphenyls PCB’s, Fuels, Polycarbonate plastic bottles including babies bottles, Food containers. Plastic film.

The main culprits are grilling, high temperature oven baking or frying of meat, fats, and starchy carbohydrates such as potatoes making crisps, chips, and baked snacks.

Acrylamide concentrations in common foods (FDA 2004 survey):

Often greater than 1000 ug/kg
Burnt barbequed meat
Grilled sweet potato crisps (chips)
Veggie chips potato snacks
Sweet Potato crisp (chips)
Roasted oat bran crackers
Veggie crisps (chips)

Usually between 500-1000 ug/kg
French fries
Pretzels
Processed baked potatoes
Ginger snap cookies
Toasted corn
Kettle crunch potato chips
Hash browns
Pitted ripe olives
Tortillas original tostadas
Low fat bruschetta vegetable crackers
Sesame snacks
Dried soup mix

Usually between 200-500 ug/kg
Butter flavoured popcorn
Crackers with peanut butter
Frozen potato skins (Frozen)
Corn flaked cereals
Corn chips
Cream crackers
Processed prune juice
Pepper toast
Coffee

General tips to avoid potential carcinogens:-
• Steer clear of heavily processed foods, containing high concentrations of additives and unhealthy fats, salt and sugars.
• Avoid excessive deoderants - have days off.
• Avoid reheating fats and oils.
• Avoid super heated snacks such crisps, chips and roasted or baked bars.
• Reduce aromatic hydrocarbons exposure by avoiding smoked, barbequed or burnt foods.
• Limit foods with high AA concentrations to small amounts.
• Try eating as much raw (healthy) food as feasible.
• Try eating more organic foods.
---end quote---

A carcinogen is anything that has been shown to cause cancer. It can be a chemical that you're exposed to (by touching, breathing, or swallowing the chemical, for example). It can be radiation, as from x-rays or overexposure to sunlight. It can be something caused as a side effect of something else--grilling food over an open flame, for example, is thought to cause a change in the food that *might* cause cancer. Think about it this way: instead of using the word "carcinogen," use "things that cause cancer." To avoid carginogens ("things that cause cancer") in your food, wash the pesticides off fruits and vegetables before you eat them. Try to avoid added chemicals in processed foods--read the ingredients list and make an effort to buy things with a short ingredients list. Eat fresh fruits and veggies whenever you can, especially if they're grown locally. You can protect yourself from cancer even more effectively by staying away from the biggies--tobacco products and overexposure to sunshine are two huge things to avoid.

And good for you for being aware of what you're eating--that's a super first step toward a healthy lifestyle!