We all know that trees are commonly chopped down and used to produce paper, but did you know that wood pulp by-products are also present in toothpaste, nail polish, towels, and even your favorite foods?
“Wood pulp” sounds kind of gross, doesn’t it? It seems like something that should only be in a lumber yard, not in our food or hygienic products. The substance is sometimes masked as “cellulose” and “sawdust,” too, but those labels are not any more appetizing.
What is Wood Pulp and How is it Made?
Put simply, wood pulp is a lignocellulosic fibrous material that is produced by separating cellulose fibers from wood, fiber crops or waste paper.
Unsurprisingly, pulp is regularly used as the source material in paper products. You can find this ingredient in everything from newspapers to toilet paper. When raw wood is transformed into pulp, the resulting product is a liquid combination of wood fiber, lignin, water and chemical by-products from the pulping process.
There are two ways that pulp is produced: chemically or mechanically.
The mechanical pulping process entails grinding wood chips into a soupy pulp of short cellulose fibers and a lot of lignin. However, this method typically yields weak paper that is only really suited for flimsy paper products such as newspapers and phonebooks.
Chemical pulping, also known as the kraft process, is the more common production method employed in modern-day pulp mills. Once the raw wood is turned into “kraft pulp,” chemicals are used to separate lignin and cellulose fibers, and that cellulose can be used to produce even stronger paper.
The most prominent chemicals used in chemical pulping are sulfurous acid and limestone, which creates calcium bisulfite when blended. When wood chips are cooked using this sulfite process, the lignin dissolves and leaves behind cellulose fibers.
Because wood is one of the most abundant raw materials on the planet, wood pulp, or cellulose, has become ubiquitous in our daily lives. This versatile wood-based fiber material has several beneficial properties: it’s lightweight, cheap to produce and isn’t harmful for human consumption.
But the fact that pulp isn’t hazardous for us to ingest doesn’t necessarily explain why it’s in our parmesan cheese, tomato sauce, ice cream, frozen foods and so on.
Wood in My Food? Why You Shouldn’t Really Worry
Chances are you have ingested a fair amount of wood pulp throughout your life. Don’t worry, though. In small doses the ingredient is harmless.
It has no nutritional value, but it can be slightly useful for people who are trying to lose weight or improve digestion. Most forms of cellulose are natural, plant-based, and a source of bulky fiber that makes people feel full.
Many food product brands such as Kraft rely on cellulose to prevent pieces of shredded cheese from clumping, among other uses. Think about popular goods like cans of parmesan cheese. Without wood pulp, the cheese would tumble out of the can in a big block. You can also find cellulose in popular brands that sell tomato sauce, ice cream, bread and dozens of other staples.
So if it isn’t hurting anyone — and even has some indirect health benefits, and allows us to enjoy tasty parmesan cheese — what’s the problem? The origin of wood pulp should offer an idea of why the ingredient has become controversial.
Pulp Nonfiction: The Origin Story of Wood Pulp
During the 1700s European bread makers realized they could cut costs and feed more people by infusing their goods with sawdust.
“At some point some clever miller was like, ‘Hey, what if we combine the flour with sawdust?’” said Penn State food historian Bryan McDonald. “‘We’re selling stuff by weight, and people don’t really have a good way of knowing what’s flour and what’s sawdust.”
Because of their efficient production, the sawdust-users eventually ran other bread makers out of business. Once people realized the high amount of sawdust had negative health effects, however, European authorities created regulations and defined exactly what qualified as bread.
Nonetheless, the practice of using sawdust spread across the world and eventually evolved into the modern technique of cooking wood pulp to extract usable cellulose.
A Modern-Day Material: Wood Pulp is Still in Your Food
Today an acceptable level of cellulose is 2-4%, according to Dean Sommer, a cheese technologist at the Center for Dairy Research in Madison, Wisconsin. Unfortunately there are still many manufacturers who try to cram cheese full of as much pulp as possible. Some of them lie about the ratio of cellulose and try to pitch the products as healthy by emphasizing the fact that they contain fiber.
In 2016 Bloomberg broke a story about Castle Cheese Inc., a company that was advertising its parmesan as 100% and then filling it with wood pulp. The former president plead guilty to FDA violations, and shortly after the company filed for bankruptcy. Despite these types of crackdowns, dozens of brands still use more than 4% cellulose in their cheese products.
Hundreds of years later, honest brands that don’t use wood pulp are still struggling to compete. To address the issue, experts such as American Cheese Society Director Nora Weisner have encouraged people to buy and grate 100% blocks of cheese instead of relying on pulp-filled cans of parmesan.
As a consumer, you might want to think about what matters to you. By purchasing wood pulp-free products, the cheddar (or paper, depending on your pun preference) you spend will ultimately get you more cheese and less sawdust.
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