What are some universal lessons learned from Fast Food Nation: The Dark Side of the All-American Meal?

Two lessons emerging from Fast Food Nation: The Dark Side of the All-American Meal relate to consumer vigilance.
Schlosser's work is designed to raise public awareness about "the All-American meal."  He does this in two distinct ways.  The first is in his display of the food preparation process.  An important lesson emerges through displaying situations like livestock care, health and safety issues, and the presence of chemical additives.  As consumers, we must be aware of what fast food corporations are doing in the name of profit to the food we eat:

The medical literature on the causes of food poisoning is full of euphemisms and dry scientific terms: coliform levels, aerobic plate counts, sorbitol, MacConkey agar, and so on. Behind them lies a simple explanation for why eating a hamburger can now make you seriously ill: There is s**t in the meat.

Schlosser demonstrates why it is so important to hold corporations responsible for the food products they generate.  There is a public health concern when we think about the mass consumption of such food.  For example, the "Happy Meal" cheerful packaging belies the chemicals used to prepare its food.  Children eating such products are unaware of the dangers.  When the most vulnerable of our society is at risk, the lesson is that consumers must be vigilant.  Consumers must be aware of food preparation practices that do not meet stringent health and safety standards. The public must hold corporations accountable for not meeting these standards.  After reading Schlosser's work, it is clear that simply trusting fast food corporations could be dangerous to our collective health.
Along these lines, Schlosser's work illuminates another lesson.  The world is no longer defined by political ideologies as much as it is defined by a globalized economic reality.  This materialist reality is far more insidious:

The history of the twentieth century was dominated by the struggle against totalitarian systems of state power. The twenty-first will no doubt be marked by a struggle to curtail excessive corporate power.

Schlosser suggests that we should be more mindful of the influence that corporations have in our world.  It impacts our lives on nearly every level. Schlosser's work details how millions of lives are changed as a result of corporate influence and power.  One of the most important lessons regarding this reality is that we need to be mindful of the excesses of corporate power. Public sector initiatives to safeguard public health and safety need to be developed and maintained.  Consumers and governments must ensure that corporations follow established rules.  Blind faith in corporations does not benefit consumers.  The need to carve out a public space where the abuse of corporate power can be effectively checked is one of the most important lessons from Schlosser's work.