Infill

I don't usually do this, but with the ongoing impact of the “pink slime” story and there's a pretty good article over at The Street about the increasing use of cellulose as a filler in food, I thought I'd write a little about food additives and adulterants.
Adulterants are distinct from additives in that additives are generally regulated and accepted in use, and adulterants are added to food without the consumers knowledge. In practical terms, additives are legal and adulterants are not.
So the use of cellulose in food is legal. Cellulose is found on the FDA's GRAS list (Generally Regarded As Safe), and so is allowed in food products. The rise in it's use is due primarily to economic pressures to keep food costs down particularly in this period of price spikes from the speculative bubble we're in. The same with “pink slime”; mechanically separated meat treated with ammonia can be added to ground meat products quite legally. Whether we want these substances in our edible food-like products is quite another story.
Adulterants in food have a long and storied history—particularly in bread. Bread, over the years, has had plaster of Paris, alum, sawdust, and mashed potatoes added to it to increase weight or whiteness and defraud the consumer. The British Medical Journal was printing arguments about the presence of adulterants and arguing about how much they mattered back in 1873.
Cellulose is a product on the FDA GRAS list (Generally Regarded As Safe), but the increasing use of filler comes from economic pressures. Commodity prices remain strong (primarily on a bubble due to speculation) and economies remain weak, meaning that producers looking to increase or maintain margins are going to be searching for cheaper alternatives to their traditional products. And food producers are turning to cellulose to add bulk and structure to their edible food-like products.
The use of additives or adulterants (the difference is whether or not the recipient knows about / wants the additive in their food. If it is iodine in salt, that's an additive. If it is plaster of Paris being added to bread, adulterant) in food has a long history, and always for the same reason: economic pressure to supply food as cheaply as possible while maintaining profits. We've seen this with the addition of melamine to milk products in China, in order to more cheaply achieve crude protein content targets. Alum, sawdust, and mashed potatoes have historically been added to bread to increase weight or the whiteness of the flour.
Food adulteration is directly tied to industrialization; both the industrialization of food production and the migration of populations out of the countryside to the cities. Low wages increase the need for cheap food, the drive for cheap food encourages adulteration.
These days, it's the GRAS list that defines the difference between adulterant and additive. That food will have additives is taken as read, as long as the ingredients appear on the GRAS list, it's generally acceptable. Consumers often disagree, as with the addition of HFCS (high fructose corn syrup) to honey. Or pink slime to ground meat products.
Of course, there's always the option of TSP, or Textured Soy Protein. But a fairly recent study shows how the manufacturing process leaves behind a residual level of hexane. Hexane is used as a solvent to separate fats from protein in the making of soy protein (well, in all fairness, not just soy protein. Its used with corn and other plants too, for the same purpose). Mother Jones has an article on the report, along with an FAQ, and Slate weighed in with an article as well. As is pointed out, there has been little research on whether or not hexane, when consumed, is a problem. It certainly is when we breathe it, but as to eating it, well, that seems to be a lot less immediately toxic. There are even alternatives; when it comes to complex processing to create vegetarian fare, mycoprotein has to be a bit better, but not by much. At least they're not currently using a neurotoxin in the process.
But as consumers, we have to ask ourselves, just how much responsibility or concern should we have for the way our food is prepared? Do we want to eat food that is killing those who gather or prepare it? Because, if so, there's a lot more research that needs to be done before we eat various things—particularly out of the industrial food system. For example, pesticides are dangerous to both farmworkers, as this EPA pamphlet demonstrates, and their families.
We create a market for such substances every time we eat food out of the industrial food system. But, as Michael Pollen said in hisWilliams College address, the food system is a fragile thing. What we do as consumers has an impact. If we don't buy something, stores will quit stocking it, meaning fewer people will buy—creating a virtuous circle. Pollen mentions that as few as fifty complaints can get a topic onto a McDonald's board meeting agenda. Positive requests have an impact also. If you ask for more local food, you create a demand that grocers will try to satisfy—meaning more downstream demand for farmers. Anything affects the way the food system acts. It really is that fragile and sensitive. So when you see local produce in your local or chain grocery, ask for the produce manager and compliment him/her. If you don't see local cheese in the dairy aisle, ask for the dairy manager and request it. This can be the politest ruckus you'll ever raise.