Tofu is considered as a processed food. After watching a couple videos on YouTube. I am only concerned about two points specifically:

  1. Is heating the soaked and crushed beans so that they become a paste harmful? As sometimes high heat can harm a food product.
  2. I don't know about the coagulant they add, which is magnesium chloride. I see that they sometimes add calcium chloride/sulfate too. Are these safe coagulants?

Nothing else I watched in the process made me think they could be harmful.

  • 7
    Welcome to SA! What do you mean by "harmful"? It's not clear from your question why cooking or magnesium chloride would be harmful. Particularly since raw soybeans are poisonous.
    – FuzzyChef
    Commented Jul 16, 2019 at 16:48
  • Hey @FuzzyChef, thanks for the welcome! By harmful I mean having any effects that can be bad for your health/body, etc... Why cooking at this temperature or magnesium chloride would be harmful is not my claim. This is a question aiming to de-mystify some myths about tofu, that I keep hearing.
    – aslı
    Commented Jul 17, 2019 at 7:44
  • 3
    Both magnesium chloride and calcium chloride are perfectly safe additions to food or water and widely used in the food industry. In fact, I don't think you can get consistent production of beer, for example, without using these additives.
    – user50726
    Commented Jul 18, 2019 at 5:26
  • 1
    I used to have to add both of those to my too-soft tap water just so I could brew tea.
    – user50726
    Commented Jul 18, 2019 at 5:28
  • 3
    Reminder: we won’t accept questions about general “health” topics. Only food safety and quantifiable questions (“does cheese or gummy bears contain more vitamin B2 per ounce?”). So please don’t ask whether something may have “any” effect.
    – Stephie
    Commented Jul 18, 2019 at 9:40

2 Answers 2


Making tofu for mass production and consumption and making tofu at home generally follow the same procedures. Soybeans are soaked, ground, and cooked. The resulting "milk" is separated from the soilds. Then a coagulant is added (either salts, acids, or enzymes depending on producer and type of tofu). Finally, the tofu is pressed. The one difference between tofu you purchase in a package and tofu made at home is that the mass-produced variety likely goes through a pasteurization step. In general, this is a process that has been used for centuries (other than the pasteurization, of course, which is more recent technology). Given the history of tofu production, and the number of people who consume it, any health concerns would have been identified by now.

  • Okay, thanks for the answer. As I detailed in my question if the temperature while heating the beans are safe and if that coagulant is a safe food additive, I have trouble understanding all this "tofu is bad because it's processed" arguments. Not all processing is harmful and I wanted to double check this with people who are knowledgeable in food processing.
    – aslı
    Commented Jul 16, 2019 at 14:58
  • 1
    @aslisabanci, I have never heard the "tofu is bad because it is processed" argument.
    – moscafj
    Commented Jul 16, 2019 at 15:01
  • I'm seeing it in many places. Apart from the "Is soy bad for you?" discussions, some people are also claiming that tofu is bad because it's "highly processed" That's how I became curious about it. I wanted to know if there are any steps involved, similar to adding nitrites while producing certain types of processed meat. So I wanted to learn all the steps. After learning a bit by myself, I wondered how safe those coagulants are and how safe the preparation temperature is. If these are also okay, then this argument is apparently a myth.
    – aslı
    Commented Jul 16, 2019 at 15:10
  • There are food regulations in place for this kind of stuff, it would of been flagged if they are harmful. Would you consider vitamins in gummy bear form processed food?
    – Huangism
    Commented Jul 16, 2019 at 17:57
  • @Huangism as I said, I don't consider every artificial matter or every food processing in the same sense. Take the example of virgin olive oil for instance. It has a certain burning degree. If a food processing step would involve heating a product that has virgin olive oil in it, above that burning degree, then I wouldn't want that. My question was to clarify these types of issues, to see if they exist or not. I don't know if food processing steps like my example are also regulated or not. I am not an expert in this, thus my question to people who are more knowledgeable.
    – aslı
    Commented Jul 17, 2019 at 7:49

Just wanted to state in addendum to all the comments and answers already given, magnesium chloride, calcium chloride, and calcium sulfate are all classified as GRAS (Generally Recognized As Safe) per the FDA.


After coming back to read the comments from the OP, I decided to elaborate a bit on the process in the interest of demystifying how industry goes about insuring the safety of food processes involved for foods like tofu.

First of all, a bit of the fundamentals and clarification on terminologies: what is "harm"? We define harm as any unintended, adverse health impact that results from the ingestion of foods containing hazards; and likewise, we define "hazards" as the unintended presence of potentially harmful elements or substances. These hazards are traditionally grouped into three major categories: physical, chemical, and biological (note: radiological and allergenic hazards have been consolidated under the chemical hazards category post-FSMA). The sciences and disciplines involved with the prevention, reduction, and control of such hazards as what is known as food safety, and just like any other branch of science, there are systematic, evidence-based methodologies deployed in the interest of mitigating aforementioned hazards. Of the existent systems, the USDA and FDA in particular enforce what is known as Hazard Analysis and Critical Control Points (HACCP) — and in more recent years in light of the Food Safety Modernization Act (FSMA), we now incorporate the more robust Hazard Analysis and Risk-based Preventative Controls (HARPC). In short, the principles and practices in these sets of methodologies allow us to quantify health hazards, and once quantified, we are able to manage undesirable outcomes based upon principles of risk management. And what is "risk"? We define risk as the product of likelihood and harm. Employing such principles, each and every individual processing step (and beyond) is analyzed and potential hazards are systematically addressed. This is enforced on the federal, local, and most of all, the retail spaces; surprising as it may seem, the driving force of food safety in the past few decades has in fact been the major retailers and international consortiums. Why? Because food recalls cost money, it's as simple as that.

This is a very gross generalization of how food safety fits into todays industries, but at least to the average laymen I hope that helps shed some light on how things work.


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