Unmasking Food Claims: Real vs. Processed Cheese

I am exploring the chemistry behind the food 'tests' originally published by the First Media company brand 'Blossom' as a YouTube video. There are 6 tests in the video; this is my research on the chemistry behind the first claim made. Caution: lots of interesting vocabulary ahead!

First claim: Under similar conditions, 'processed cheese with chemicals is difficult to melt'; natural cheese melts easily.

Questions raised: What does the term 'processed' mean, as it relates to cheese, and what chemicals are used in making processed cheese?

According to the FDA , processed cheese - actually it is more correct to call it process cheese - is prepared by reducing natural cheese particles in size ('comminuting '), mixing these cheese particles with an emulsifying agent (a substance whose purpose is to keep a reluctant mixture of small particles called an emulsion mixed up after you stop physically stirring it), and then carefully heating (at least 30 seconds, and at a minimum temperature of 150 degrees F) the mixture in order to pasteurize (kill bacteria and prevent or at significantly delay food spoilage by inactivating the natural enzyme phosphatase) the mixture. There are strict guidelines for moisture content, fat content, percentages allowed for each type of cheese used when making a blended cheese product, taste additives (like salt or food flavorings like liquid smoke), artificial colors, and other additives (water) aimed at improving texture, consistency, or to further inhibit spoiling. In addition, and I was surprised by this, there are very specific rules about how to name the cheese product. For example, when the product can be called 'Pasteurized Process Cheddar Cheese' or 'Pasteurized Process Gruyere Cheese', versus when it has to be called 'Pasteurized Process Cheddar Cheese Blended with Colby Cheese'. There are also only specific blends of cheeses which are allowed to be called 'American' cheese.

As the previous paragraph implies, there are a variety of substances added to the cheese particles over the course of the processing. To call them each a chemical is a bit misleading, from my point of view, because everything that is not energy is matter, and all matter is some kind of chemical. Nonetheless, I understand as well as you do that calling something a 'chemical' has the cultural implication of some kind of artificial (man-made) substance, often with negative connotation. The FDA keeps a tight rein on food additives of all kinds (for more info on FDA definitions of additives, click here ). These general classes of chemicals are summarized below:

• Natural cheese - milk (a natural emulsion of water, milk proteins called caseins, sugars like lactose, and fats) that has been allowed to 'curdle' through controlled bacterial spoilage. The sugar - lactose - is the food source for bacteria, which converts the sugar into lactic acid. This acid affects the pH of the milk, and at a specific point, an substanced called rennet (obtained from the lining of calf stomach; rennet contains the enzyme chymosin ) is added which enables the emulsion to break into globs of casein and fat (there are plant-based enzyme substitutes available). The globs are the curds and the remaining liquid (mostly water and lactic acid) is the whey. (Remember little Miss Muffet? She was making cheese when the spider showed up.) Straining off the whey and collecting the curds into molds ends with finished cheese. Different milks (goat vs. cow, for example) can make different cheeses, and different regions of the world have different bacterial blends which result in different flavors and textures. The length of time the cheeses set in molds, and other factors also impact the final cheese product.

• emulsifying agent - added to keep the milk proteins, water, and fats uniformly blended throughout the life of the product. Naturally, fats and water are insoluble (they don't mix easily if at all, and if they do, they don't stay mixed.) Think of an oil-and-vinegar salad dressing. Vinegar is usually around 95% water. Oils and fats are long chains of carbon-based molecules, and water is a very small molecule made of hydrogen and water. These molecules are structurally very different, and chemical behavior is often directly linked to molecular structure. Because fats, water, and proteins don't easily mix shoulder-to-shoulder, we add emulsifying agents to enable this association. Common emulsifying agents in cheese are tartaric acid, lecithin, or xanthan gum, among others.

• salt - sodium chloride, added for taste. Most people understand 'salt' as this specific chemical compound, but the chemistry definition of salt is much broader. A salt is actually a classification used for any chemical compound which is composed of 'ions' (atoms that have a positive or negative charge because electrons on these atoms have moved around). Every salt has a positively-charged component (the positive ion, aka 'cation') and a negatively-charged component (the negative ion, aka 'anion'). In sodium chloride, the sodium is the positive ion, and chlorine (called chloride) is the negative ion. If you are interested in understanding the naming of salts, see the link below in Additional Online Resources.

• flavorings - added to give flavor to both natural and process cheeses. You wouldn't believe the huge list of flavoring compounds available for cheese. I looked through the website for the company called Edlong , which is a company specializing in dairy product flavorings. In the cheese flavoring category, I looked up a few flavoring mixes for cheddar cheese, and most of them are organic acids like hexanoic acid, octanoic acid, butanoic acid, and 3-hydroxybutan-2-one. Don't be worried - these kinds of organic acids are found in natural cheeses also, as a result of the ripening processes accomplished by the bacteria and enzymes, so I don't feel that classifying them as 'chemicals' in the negative sense is appropriate here.

• colorants - added to give the cheese a more acceptable color. Most American consumers are used to cheese having a yellow or off-white/cream color, and so cheeses marketed to these consumers will do better with a more yellow or creamy-yellow hue. Common natural colorant compounds come from the carotenoid family (see the word 'carrot' in this term?) or from extracts of turmeric, paprika, or annatto. Annatto's main colorants are bixin and its chemical relatives. Are these compounds 'chemicals' in the negative sense? No. All of the compounds used for natural colorants are biologically and biochemically familiary to our bodies. Great info about cheese colorants like annatto can be found at Cheese Color - The Cheese Science Toolkit . What about other colorants like Yellow Dye 5 and Yellow Dye 6, which used to be used in Kraft products like the famous "Blue Box" mac'n'cheese? These artificial colorants have been eliminated from the company's cheese-making processes because of known health risks (which include, according to the Food Network: allergic reactions and some specific tumor risks ) posed by these colorants (here's a decent article about Kraft's decision: "Kraft Removes Yellow Dye from Mac & Cheese "). I would personally call these artificial colorants 'bad' for human health. Most American and western process cheese is now dyed with spices like annatto. That's good news.

• anti-spoilage agents - added to prolong shelf life of cheese products. These compounds are definitely chemicals. According to Jalilzadeh, Tuncturk and Hesari (2015), "Green pepper, sorbic acid, sodium benzoate plus benzoic acid and?hydrogen peroxide , nisin, natamisin and chitosan as additives have been used for prolong cheese shelf life." Except for green pepper, which contains a mixture of many natural compounds (which fall in classes of alkaloids, flavonoids, polyphenols, and sterols, according to authors Koff-Nefri et al, 2010 ), all the other items in this list are specific chemical compounds. Sorbic acid is a naturally-sourced compound originally isolated from the berries of the Mountain Ash tree. It's natural antimycotic activity makes it a great additive for cheese which contains fats that are sensitive to spoiling by mold. Benzoic acid is an organic acid, and sodium benzoate is a sodium salt of benzoic acid. Both benzoic acid (not particularly water-soluble) and sodium benzoate (water-soluble) have the ability to interfere in bacterial production of energy through processes like the citric acid cycle , which breaks down fats into energy. Nisin is the one mentioned most as a common bacteriosin (a compound made by lactococcus lactis bacteria to combat, kill, and chemically defend against similar bacteria), natamisin (aka natamycin , pamarisin, or pamarycin) is a fungicide (a compound that has the ability to kill certain types of molds and fungi) also produced by a strain of bacteria, chitosan (source: the exoskeletons of shellfish) is antibacterial in its ability to physically and fatally damage bacterial membranes (PubMed article on chitosan: abstract here ). Finally, hydrogen peroxide may be added to prevent the growth of bacteria through fatal damage to bacterial membranes and cell walls. Read the article below by Finnegan et al (2010) to learn more about the mechanisms attributed to hydrogen peroxide's ability to act as a food preservative.

So now finally to the response to the claim: Does the ability of process cheese to resist melting indicate some measure of being 'fake'? And, as an extension of this thought, is process cheese harmful to health?

Answer: No. The ability of process cheese to melt at a high temperature than natural cheese reflects only the fact that the cheese blobs that were in the natural cheese starting material have been straightened out by the rennet. This strengthens the ability of the casein protein chains to cling to each other and to the fats present in the cheese, and allows more heat energy to be absorbed without breaking these associations. In natural cheese, the blobs of protein, fat and water are unevenly distributed and the blobs themselves are held loosely to each other. A lesser amount of heat is required to separate the blobs from each other, and this is visible in the quick melting of natural cheese. As far as the label of being 'fake', my answer is also unequivocably no, because all the ingredients used in process cheese are materials which are scientifically known and understood, and most of them are either naturally sourced or are created synthetically to be identical to the naturally-sourced (interpret this to mean limited natural resources) substance. To help you understand that not all synthetic things are harmful, consider the fact that vitamin C tablets contain the exact same chemical compound as the vitamin C found in orange juice. To be 'synthetic' most accurately means chemically identical though man-made. To be 'artificial' means man-made, but not necessarily chemically identical. For example, nylon is an artificial silk. The chemical structure of nylon has some distinct similarities to silk, but silk is a complex product which cannot be duplicated by human processes.

As far as health is concerned, I am no dietician, but the fat in natural cheese is harmful if consumed in portions that are too large. The relationship between heart health and the amount of fat (cheese fat is primarily saturated fat) is well established. There is still fat in process cheese, so the portion size matters here, too. What about the 'chemicals' in cheese, process or otherwise? As I have said before, everything, including the structures and functions of the human body and our entire planet, is chemical in nature. The problems only arise when the chemicals we put into our bodies are ones that our bodies are not designed to break down. All of the additives in modern process cheese are not any more toxic than the organic compounds present in natural cheese (to which colorants and flavorants are also sometimes added).

Additional Online Resources:

1. Process Cheese: Scientific and Technological Aspects - A Review - A Kapoor - 2008- Comprehensive Reviews in Food Science and Food Safety - Wiley Online LIbrary
2. Milk Fat Globule Structure and Function; nanoscience comes to milk production - Argov, Lemay and German - 2008 - Trends in Food Science & Technology
3. How to Make Cheddar Cheese - Traditional Method - Little Green Cheese
4. Naming and Identifying Salts - St. Olaf's College
5. How 17th Century Fraud Gave Rise to Bright Orange Cheese: The Salt - NPR
6. Abbas Jalilzadeh, Yusuf Tuncturk and Jvad Hesari, 2015. Extension Shelf Life of Cheese: A Review.?International Journal of Dairy Science, 10: 44-60. DOI: 10.3923/ijds.2015.44.60.
7. Michelle Finnegan, Ezra Linley, Stephen P. Denyer, Gerald McDonnell, Claire Simons, Jean-Yves Maillard, Mode of action of hydrogen peroxide and other oxidizing agents: differences between liquid and gas forms,?Journal of Antimicrobial Chemotherapy, Volume 65, Issue 10, October 2010, Pages 2108–2115,?https://doi.org/10.1093/jac/dkq308 . Available at https://academic.oup.com/jac/article/65/10/2108/707615 .