Source: UC Davis; Certified Organic Farm 

You may think you know everything about your organic food -- but you don't. There are major misconceptions about this $35 billion industry. Here are the five biggest myths about your organic food.

1. Organic products are 100% organic.
The United States Department of Agriculture, or USDA, isn't a zero tolerance regulator. For any multi-ingredient "organic" product you pick up, from
Wal-Mart (WMT -0.65%) to Whole Foods Market (WFM), only 95% of its contents have to be certified organic.

For the USDA, it's a matter of convenience and feasibility. Testing for 100% full compliance of anything is a regulator's worst nightmare. Additionally, some ingredients simply don't have organic options on supply. The USDA does note, however, that investigative eaters can take a closer look at the ingredients list; if a specific ingredient is labeled as "organic," then it is. And for those American agricultural complex skeptics, the European Union has its own 95% rule.

2. Organic crops aren't fertilized.
There's more to your organic arugula than meets the eye. Fertilizers are used to replace necessary soil components that constant cropping removes. Nitrogen and phosphorous, specifically, are two main ingredients in the fight for fertilizer.

While the USDA forbids farmers to use sewage sludge (yes, this is actually a common non-organic addition) or synthetic fertilizers on their organic fields, they're free to use most other fertilizer types. Among the more recognizable additives are animal manure, compost (which can include animal materials), and ash.

3. Your organic meat grazed for grub.

Source: USDA.gov 

Organic meat was once an organic animal. But that doesn't mean that Mr. and Mrs. Moo spent their days grazing in the grass. While the USDA requires that animals spend at least 120 days a year munching away on organic pastures, just 30% of its nutrition must come from the pasture itself. And in the off-season, 100% of its sustenance can come from organic feed.

4. Organic farmers don't use pesticides.
As with fertilizer, organic farming isn't as far off from conventional agriculture as some would think. A 2010 poll showed that a whopping 69% of those surveyed believe organic crops grow up big and strong sans pesticides. While the USDA does have a three-page long list of prohibited synthetic pesticides, there are over 20 chemicals that make the cut. Even more worrisome, current organic regulations don't include any limits on usage, meaning less effective approved pesticides can be piled on to organic farms, creating a cadre of potential health and environmental issues of their own.

5. Organic farming is environmentally friendly, tastes better, is healthier, and will improve your sex life.
OK, so maybe that last one applies more to vegetarians than organic eaters, but the point remains. There's a lot of hype around organic food, and it's important to remember that, in terms of rigorous evidence, causal inferences are few and far between. As organic farming becomes increasingly mainstream, a lot of its original attributes aren't nearly as applicable.

On the environmental front, intensive large-scale organic operations can be much worse for the environment than your local farmer who uses synthetic fertilizer once a year to keep production levels competitive. Likewise, personal perceptions on taste and health may actually be little more than a placebo effect, helped along by a fast-growing $35 billion dollar organic industry that wants you to buy their product.

Organic agriculture is an exciting opportunity for the future of food. But knowing the hard facts of organic food will help you to be the best, most informed consumer you can be.