The funny thing about being a food scientist, is that before meeting me, most people have never even heard of my field. Yet, almost instantaneously after pleasantries, I am bombarded with any, and every food-related question they’ve ever had. My phone has become an emergency helpline for all food-related inquiries.
I’m pretty certain I spend 50% of my day answering questions from family or friends on whether or not food is safe to eat. There was a call from an old roommate who hard boiled eggs at night, forgot about them, and only put them in the refrigerator when she realized her mistake the next morning.
A countless number of questions about meat being safe to eat after sitting out at room temperature. Is it safe if it was only sitting out for two hours? Four hours? Overnight‽ Please, I beg you, stop leaving meat out on the counter! My advice is to never chance it with questionable meat. Risking your health is just not worth it, unless you enjoy nausea and explosive diarrhoea.
There is however, one mistake I see people make over and over again: throwing out perfectly delicious cheese that they mistake has mould growth. As a Wisconsinite, this just breaks my cheese-clogged heart, so let me introduce you to crystallization in cheese.
If you are an avid cheese-monger or turophile, you may be familiar with the appearance of white crystals on the surface or interior of your cheese. Tiny, pin-head size bumps that appear out of nowhere, or longer ones that develop into one continuous smear of white.
To cheese experts, the crystals symbolize a high-quality cheese, aged to develop a full-bodied flavour. But to consumers, the white bumps can be mistaken for mould and yeast growth. They often think of them as a defect or a spoilage, rather than a sign that the cheese is actually better.
The truth is, the harmless crystals are a natural part of ageing cheese. When people throw them away thinking they’re spoilt, they end up with a lot of unnecessary food wastage.
Actually, all cheese making produces quite a bit of wastage. On average, if a dairy starts with ten-thousand pounds of milk, they’ll end up with only a thousand pounds of cheese. The remaining nine-thousand pounds ends up as whey while the curd is formed.
That’s right: if you run the numbers on cheese manufacturing, the percent yield is only about 10%.
Even more mind-blowing is the fact that, only a couple decades ago most dairies didn’t do anything with the whey. They just chucked it into water sources, completely devastating any wildlife in the process. If you look at the location of most dairies, especially older ones, you’ll notice they were built right next to a river or lake — and now you know why.
Luckily, dumping is now illegal in most places. This has forced the dairy industry to find a use for their by-product, which is why “whey protein powder” has exploded in popularity. Dairy chemists realized that the liquid whey was an excellent source of protein, and can be dried into a powder.
So, all you whey-protein guzzling bodybuilders can thank cheese for providing your muscle-making powder. But, let’s get back to the crystals.
I’ll never forget the day one of my roommates was angrily stomping around our shared kitchen. Afraid something was wrong, I went to investigate. I found her just about to toss out over half a block of cheese in order to “save” the rest from mould growth.
She went on to complain how she had just bought the cheese, so I had my suspicions about the “spoilage.” I asked to have a look, and sure enough, it was just calcium lactate crystals forming on one side.
This is quite understandable. Often, crystals end up looking like yeast or mold growth, which of course you should definitely not be eating. But if you’ve recently purchased your cheese, as well as properly handled and stored it, I wouldn’t worry about spoilage.
My roommate likely didn’t tightly seal the product after the first opening. Loose packaging allows for increased exposure to air and a spot for moisture to accumulate, which helps the crystals form.
There are many kinds of cheese-crystals, but the two most common ones are formed by ‘calcium lactate’ and ‘tyrosine’. Both these crystals are the result of bacterial activity, but they’re not at all dangerous.
Have you ever noticed a burning in your joints, after a heavy round of exercise? That’s the feeling of ‘lactic acid’ building up.
There are two ways your body can convert its stored up reserves to energy: with oxygen, or without. The with-oxygen version is much more efficient, but it needs oxygen to run — and when you’re doing a lot of heavy exercise, that oxygen starts to run short.
That’s when your body switches to the oxygen-free process, ‘anaerobic respiration’, which releases lactic acid as a by-product. Lactic acid is what builds up near your muscles to give the burning feeling. But don’t worry — it’ll get released later, when oxygen comes in, turning into harmless carbon-dioxide and water.
Incidentally, lactic acid is also part of what forms the calcium-lactate crystals in cheese.
Cheese, as you know, is made using “starter culture”. That’s basically a bunch of bacteria that help the milk ferment. The bacteria metabolise in a similar anaerobic way, converting sugars in their bodies to energy, and releasing lactic acid as a by-product.
In cheese, lactic acid doesn’t go away or turn into water. It sticks around. And, when it gets in touch with calcium, which is naturally present in cheese, the two combine to form calcium-lactate crystals.
Calcium lactate crystals are the most commonly encountered crystal in cheese. They are often found in aged cheddar, parmesan, and gouda, where you can see them as long, white streaks or smears along the surface.
If the cheese is not tightly packaged, or carefully resealed after opening, you will likely see calcium lactate crystals aggregate in this area. The crystals are soft, white, and sometimes appear damp.
So if you see these crystals, it doesn’t mean the cheese has gone bad. On the contrary, the cheese is now even better than before, because the crystals add a unique texture to the cheese!
Apart from lactic-acid crystals, ‘tyrosine’ crystals are the other common type. You may see them as discrete white dots. Each the size of a needle-point, a bright white in colour, and leaving a gritty mouthfeel, they usually come on the inside of hard Italian, Dutch and Swiss Cheeses.
Tyrosine crystals are usually linked to the presence of a bacterium named Lactobacillus helveticus, or L. helveticus for short. Cheese makers like to use this bacteriumsince it gives their cheese a unique flavour.
The catch is, L. helveticus has enzymes that breakdown proteins, which release amino-acids like tyrosine. Those enzymes are so efficient, they generate many more amino acids than the bacteria need to survive. They leave extra tyrosine lying around — and there come the crystals.
Alarmed that my roommate was about to waste her food and money, I polled the seven other people who also lived in our house. I was disappointed to find out they all identified the white markings on the cheese as microbial growth, not crystals. They were in agreement that the cheese was spoiled.
As a food scientist, such situations fuel my belief that we need more science articles to be expressed in layman’s terms. (On the positive — though selfish — side, the situations also provide me with excellent ideas for my next writing piece).
Cheese crystals may seem visually unappealing at first, but over time, you may find yourself looking forward to them. They are completely harmless and provide a crunchy, alternative texture to the cheese.
Soon enough, you’ll start seeing those white streaks and bumps not as a blemishment, but as an indicator of a good, finely-aged cheese.
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