9 Everyday Products You Didn't Know Had Animal Ingredients

If you thought that by quitting meat or at least going vegetarian during the week you were doing your part to avoid factory farming, think again.

Even though animal products might not be in as many places as some think (for instance, most "catgut" tennis rackets are made with synthetic materials now) they spread far beyond just those hidden in food: everywhere from your car to the bathroom and the sky on the 4th of July.

In short, after an animal is slaughtered, its byproducts are sorted into edible and inedible parts. Approximately 55% is considered an edible byproduct, while the remaining 45% is classified as inedible. These inedible animal byproducts are used in a variety of industries, including cosmetics, fabrics, pharmaceuticals, and more.

1. Plastic Bags

Many plastics, including shopping bags, contain "slip agents," which reduce the friction in the material. What are those made of? Animal fat.

In a more technical explanation from Genetic Engineering and Biotechnology News: "Although polymers are manufactured from petroleum feedstock, plastics manufacturers often use additives of animal origin to improve material properties and/or to aid in processing of raw polymers."

Also, watch out for new plastics coming out: Researchers are experimenting with keratin protein found in chicken feathers to produce plastics, adhesives and non-woven materials.

2. Car and Bike Tires

Even when food can have hidden animal ingredients, you can still take the time to look at the label to see it. With your car or bike tires, it's a little more difficult. But here's the trick: check with the manufacturer if their stearic acid is animal-based or plant-based. Stearic acid is used to help the rubber in tires hold shape under steady surface friction.

3. Glue in Wood Work and Musical Instruments

Animal glue (made from the boiling of animal tissue and bone) is used as an adhesive for building and repairing musical instruments in the violin family. Other synthetic glues can also be used, but hide glue is considered the standard. Hide glue is also used in antique restoration and other specialty woodworking.

4. Biofuels

Sugar cane and corn are what come to mind at first when we think about biofuels, but over the past years the use of animal fats to produce these has extended.

There's actually beef biodiesel (which Matthew called a "bone-headed idea" last year) and chicken biodiesel to choose from.

5. Fireworks

The same component used in the tire industry, stearic acid, is present in the production of fireworks. Stearic acid is used to prevent oxidation of metal powders so that the firework compositions can be stored for as long as possible.

6. Fabric Softener

Downy fabric softener contains Dihydrogenated tallow dimethyl ammonium chloride, which comes from the cattle, sheep, and horse industry. They sure won't put that in the usual 'all-so-soft' advertising.

7. Shampoo and Conditioner

Annie Leonard warned us about the hazardous chemicals in the cosmetics industry, but didn't necessarily emphasize the animal ingredients.

According to PETA, there are more than 20 components from animals that could be in your shampoo and conditioner. The tricky part is when you read "Panthenol", "Amino acids", or "Vitamin B" in a bottle (just to name a few), it can be either from animal or plant source -- making it hard to tell. Some companies make a point to avoid communicating details about ingredients and production processes to avoid putting off consumers.

Best way to be sure? Look for vegan brands or products which state that no animal products were used.

8. Toothpaste

Glycerin is found in animal and vegetable fats. When separated out, glycerin is used in a wide variety of products, including toothpaste. As with some other ingredients, when you read 'glycerin' on shampoo and conditioner, it can be either animal or plant based. But many commercial brands like Colgate claim their products do not contain ingredients derived from animals, including glycerin.

9. White and Brown Sugar

What about hidden products in the manufacture process? Among vegetarians and vegans, it's known that purified ash from animal bones is used in filters to refine sugar by some brands, though there are other companies that use filters with granular carbon or ion exchange systems. What not all may know is that brown sugar is also refined, only to have molasses added after.

You can opt for unrefined organic sugar or choose the brands that PETA says are vegan.

It's important to note that getting to know where animal products go is not just for vegetarians or vegans: These byproducts are very likely not sourced from responsible organic farmers, but from the abysmal and extremely polluting factory farms. So even if you're a conscious omnivore, watch out.