This is a topic that most Americans are unaware of, but is still pretty important. If enough people let me know that it's worth me spending a while on gathering all the reference data, I'll write something here detailing all of the problems.
Basically, the food supply in the U.S. is mostly garbage. If you've ever been out of the country, it seems like pretty much everywhere else has better quality meats, vegetables, and fruits. There is a reason for this, and things are a lot worse than you know.
My wife recently read the book
Fast Food Nation, which, along with
The Jungle, give you a pretty disturbing look into what we eat. At this point, she's pretty much afraid to eat anything, and I'll give a few reasons why here:
Meat
The meat that we get comes from about 5 different companies that own the slaughterhouses and are big corporations of farms. These are not farms where cows roam a plain and eat, but they are farms where the cows are stuck in feedlots for their entire lives, injected with hormones, and fed proteins such as the remains of other dead cows. It's a lot like "The Matrix" but for cows.
When the cows are slaughtered, it is usually done in such a rapid pace that it is very sloppy. Intestines are usually cut open, and feces literally sprays all over the raw meats. The humans that work in these slaughterhouses often lose limbs or cut themselves as well, and this sometimes ends up in our meat supply as well. Human blood, cow shit, dirt from the floor, cleaning chemicals, etc are in our meat. This is why we have a problem with e coli. Where my wife grew up in Mexico, meat is a lot fresher, and the butchering is done at a slower pace as it used to be done here. The result is that you don't have to treat your food as a biohazard because it isn't full of shit and other unclean things. It's still not perfect, but it's better than how the meat you get at restaurants or the grocery store is in the U.S.
The way around this is to do what my family did when growing up. You buy a huge freezer, and buy meat from local farmers that slaughter their own cattle. It's good because 1) you support your local community, 2) the meat is safer than the corporate shit-infested meat, 3) you can see how the cows live and what they are fed and that they are most likely not injected with hormones, and 4) you don't have to go to the groceries because you have a huge supply of meat that is most likely delivered to your door. While some people might find this unsafe because they think, "how do I know I can trust this farmer selling it to me", I assure you that there is absolutely no enforcement that the meat you get in the store will be of any good quality. The USDA is a rubberstamping joke.
Fruits and Vegetables
Most of the fruits and vegetables we get are full of chemicals. Whether it's the pesticides used to control the insects, the dyes used to make them look fresher or more appealing, or the chemicals used to make them grow bigger or ripen faster, our fruit supply is full of bad things too. An interesting thing I've observed is that much of our fruits are imported. However, when you go to the countries that these foods are imported from, what the people there eat tastes better. Bananas are a great example, because they go through a process of making them look ripe so they can sell in the stores. They are sprayed with chemicals that make them turn yellow on the outside even though they are still unripe on the inside. Tomatoes are often dyed with red dye so they look more appealing.
The solution to this problem is generally to buy your food from farmers markets and other small local farms if possible. The quality of this food tastes better and is healthier for you than what you get in the stores anyway.
Seafood
We pollute the crap out of the oceans, so is it any wonder that tuna is unsafe for pregnant women to eat? Seafood in general is full of pollutants and chemicals, particularly the fish that stay towards the bottom. Everything that we make that is nasty and unsafe for us to consume ends up in our seafood. They say that eating seafood is healthy, but that is only if it doesn't have rocket fuel and mercury in it.
Politics
There are effectively no safeguards on our food. Things that the Bush administration have done to weaken the USDA and our dietary security are usually not all over the news, but they are just as alarming as giving no-bid contracts to Halliburton for Iraq, or how his family has business ties to the bin Ladens. For example, the act of making meat be irradiated before sending it out sounds good, but it also included rolling back some of the safety guidelines that were previously in place. The result is that while the bacteria in your meat is killed before you buy the meat, the slaughterhouses have relaxed their already unsafe sanitary requirements and so we have more fecal matter in our meats than before. Bush is just following a long line of Republican presidents and politicians have have worked to erase any of the improvements that Roosevelt and others have made to clean up our food supply. With the advent of corporate farms who make short cuts with chemicals, relaxed safety and sanitation, as well as taking away our choices on where we get our food from, we have effectively created a situation where we all eat poison in every meal. Clinton tried to stop it, but the big food corporations have more power than the president, and the paid off congressmen (including Newt Gingrich, who got a lot of money from the meat industry) watered down the bill representing Clinton's ideas to a point where it was joke.
Conclusion
I don't like this any more than you do, and I think that if most people were aware of what is going on they'd be really angry. There are categories of this topic that I haven't even touched on but are just as important, such as how excessive amounts of fat, sodium, and sugars are in our foods. How the corporations cover up things like this, such as claiming something as sugar-free but using "sugar alcohols" (aka another form of sugar) in the food to make that claim. Saturated fats need to be touched upon, and in particular trans fats. I haven't discussed the chickens that our food comes from, which one judge referred to as "Frankenchickens" because they are so genetically and chemically altered for us to eat. I haven't touched on the fact that the vast majority of the food we eat has it's taste created in a perfume lab because the food is so old and of poor quality that they have to put chemicals on it so it tastes ok. A few books can be written about this, and it would be so shocking that most people wouldn't believe it. My wife now knows this stuff, and it scares her so much that she doesn't want to eat food in the U.S. anymore, but realizes she has to. It's disturbing.