Have you seen this on the internet yet, or more likely on some social media page? The first time I saw a comment about store bought pre-shredded cheese being “toxic” it was a fitness influencer on a social media story. I’m sure the whole neighborhood heard my eye roll. Seeing that made me wonder, what are they talking about, so I started looking into to what this claim was, because of course the IG story had no information or evidence to back the claim.
First, let’s clarify what toxic is. According to Merriam-Webster online Dictionary “Toxic” has several meanings:
1) containing or being poisonous material especially when capable of causing death or serious debilitation.
2) exhibiting symptoms of infection or toxicosis
3) extremely harsh, malicious, or harmful
toxic sarcasm
4) relating to or being an asset that has lost so much value that it cannot be sold on the market
Additionally, when considering the use of the term "toxic", it is important to remember that the dose makes the poison. For example, water is crucial for life. Without water, most living beings die within a few days. At the same time, water toxicity is real, and people die every year from water intoxication. If I’ve missed a case of toxic pre-shredded cheese poisoning ever being documented, please let me know.
So, why are people claiming that shredded cheese is toxic? There are several reasons people think pre-shredded cheese is not a good product. Using the term “toxic” is nothing more than sensationalism to get likes, follows, or people reading their articles, not because they have any evidence of actual reported cases of pre-shredded cheese toxicity.
One argument made for why shredded cheese is “toxic” or not good for you is as simple as the excessive use of ingredients. Most arguments are based on health concerns of those additional ingredients. The additional ingredients in shredded cheese serve several purposes, though, including reducing the likelihood of mold, yeast, and fungal growth.
What are the additional ingredients and why are people choosing to avoid them?
Cellulose/potato starch – The purpose of adding cellulose or potato starch to pre-shredded cheese is to keep it from sticking together and absorb moisture in the bag. If you’ve ever pre-shredded a block of cheese and stuck it in a bag for future use, it tends to stick together and is not as easy to use in the shredded form. It also will go bad more quickly due to the extra surface area exposure to air and potential moisture build up, which can cause mold, fungus, and yeast to form. There is no evidence or research that cellulose, or potato starch has any negative impacts on human health unless you happen to be sensitive to these ingredients. Cellulose is added to several food products to increase insoluble fiber in those products.
There is a drawback to adding cellulose and potato starch to pre-shredded cheese. It has a negative impact for some culinary uses, such as sauces. The powdery substance of the added cellulose or potato starch will change the texture of the sauce, which while is not ideal, it certainly is not toxic in the respects to physical human health.
Calcium Sulfate – One of the arguments I read about why this anti-caking ingredient is sometimes used in shredded cheese is because “it’s used to make ground cement and making tiles. Do you really want that in your cheese?” The appeal to emotions here is strong but misplaced. Calcium Sulfate is used in a wide variety of foods in insignificant amounts. It has been classified as a GRAS (Generally Recognized as Safe) substance by the FDA, as well as the European Food Safety Authority. Again, the dose makes the poison. Just because a small quantity of an ingredient happens to be used for non-food purposes does not inherently make the food toxic that should be avoided. There are several mineral compounds found in food that can also be used for non-food manufacturing. Iron, zinc, and copper all have functions in the human body, as well as in manufacturing.
Ferrous Oxide has several industrial uses including iron ore, cleaning jewelry, and in cosmetics. It is also used in the food industry to fortify food with iron. Zinc oxide is used in sunscreens and to prevent diaper rash. Zinc Sulfate has been used in treatment to prevent moss on roofs and fertilizers, amongst other non-food uses. Both are also considered safe for human consumption as a zinc supplement or fortification of food.
Natamycin – I suspect this is the ingredient that people are really referring to when they claim shredded cheese is toxic.
Natamycin is an anti-fungal added to shredded cheese, and many other foods, to prevent mold, yeast, and fungus from forming.
The least compelling argument here is that natamycin is produced by fermenting a naturally found bacteria in soil, and who wants to eat something that comes from a dirt bug in soil. Except, all food comes from soil, in one way or another, so avoiding an ingredient because it comes from soil is not a valid argument.
Other arguments for avoiding Natamycin or calling it toxic is because there are several medical applications for treating yeast and fungal infections, including a treatment for an eye fungus. Again, the appeal to emotion about why would we eat that? The amount added to shredded cheese is minimal, especially compared to the dose used for medical treatments. Using Natamycin is to prevent mold and fungus from forming. Consuming mold or fungus from cheese can in fact be harmful to humans in a high enough dose. It also extends the shelf life since shredded cheese has more surface area exposure to air, which increases risk of mold and fungus formation.
Research studies are being used to support claims that Natamycin is toxic to justify why it is on some individuals personal avoid list or why Whole Foods included it on their list of unacceptable ingredients for food has significant limitations and flaws.
The most egregious I saw was an MD linking 3 studies on their website to justify adding Natamycin to their list of foods to avoid. The first one was a study from 2009 claiming it would cause DNA damage. The study linked was not a human trial and involved treating human cells in various concentrations of Natamycin solution for 24-48 hours. When we eat food, however, our cells are not sitting in a high concentration of Natamycin for 24-48 hours. Not surprisingly, the MD who is biased towards not consuming Natamycin did not include a link to a study from 2014 that used the actual ingestion of Natamycin to determine that there is a negligible or low toxicity effect from its ingestion.
Another study, on mice, used by the MD was retracted and corrected by the author due to some fundamental scientific errors. The MD linked the summary of the article that only had a name correction. If you follow the link to the Full Article, it clearly states the study has been retracted by the author. In final study this MD linked, he implied in a heading that Natamycin may cause digestion problems by interfering with the bacteria in our bowels. Natamycin does not act against bacteria, though. It is one of its advantages to using it since it does not contribute to the overuse of antibiotics that are linked to antimicrobial resistance. The study link on the MDs website takes you to the summary of an article called “The gut flora as the forgotten Organ”. There is no mention of Natamycin in the summary available through the link on the MDs website, nor is it mentioned, or any antimicrobial, in the full text.
Finally, it is not just the U.S. Food and Drug Administration that has approved the use of Natamycin as a food additive. Canada Health, European Food Safety Authority (EFSA), Joint FAO/WHO Expert Committee on Food Additives (JECFA), as well as other authorities have also approved the use of Natamycin in food. I’ve heard more than once from people that they are concerned the United States allows food additives banned in other countries. It would seem most countries are on board with the use of Natamycin as a food additive.
With that there are some individuals who are sensitive to ingesting Natamycin. Obviously, those individuals would be better off avoiding pre-shredded cheese treated with Natamycin. However, just because some people have a sensitivity to an ingredient does not necessarily equate to toxicity, though.
What is frustrating as a nutrition professional are people on social media and blogs spread misinformation to influence others. Or, in the case of an Instagram Story of a fitness professional passive-aggressively shame others for using store purchased pre-shredded cheese.
There is no reason to shame people for being busy and choosing a quicker alternative. If you choose to avoid an ingredient, or are sensitive to it, it does not mean everyone should avoid it. Using social media status or the authority of your profession, such as an MD, to try to shame and fear people into avoiding certain foods is the opposite of helping. Addressing the real health issues of a food, such as the saturated fat content of cheese, and keeping the content evidenced based with a body of research behind it, not a few selective articles to support a bias, is our role. Fear mongering is not.
The only other argument I’ve seen against the use of shredded cheese is the cost. At the stores I shop at, the cost per pound of shredded cheese and block cheese are typically the same. Often shredded cheese is less expensive per pound than block cheese. When it saves you time shredding and cleaning additional kitchen utensils, there is an additional cost savings of your time.
Shredded cheese can have several advantages over block cheese. Saving time with meal preparation is a huge bonus for many hard-working individuals with limited time. Using shredded cheese also saves cleaning up a cheese shredder. Personally, I do not enjoy cleaning food shredders, especially after using them to shred cheese. If you are making a cheese sauce from scratch, you’re definitely better off using block cheese. In that case, I suggest cutting the cheese into small blocks rather than shredding them to save time and from having to clean an extra utensil.
So, if you like the convenience of packaged, pre-shredded cheese, you can feel comfortable knowing it is not toxic and there has never been a documented case of toxic shredded cheese poisoning. If you prefer shredding your own cheese from block, go for it! You will burn some extra calories by shredding the cheese and prefer the taste. If you are shredding a softer cheese, like mozzarella, you can stick the block or ball in the freezer for 20-30 minutes to make shredding easier.
Make the choice that is best for you but let’s not worry about whether other people opt for block or pre-shredded cheese when purchasing cheese.