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The Truth About Almond Pasteurization Methods

While there are four main methods of pasteurizing almonds, steam processing, high heat treatment (roasting), blanching and highly toxic fumigation treatment with propylene oxide (PPO), two of them are the primary methods that are used most often.. These two are steam processing and PPO fumigation.

Steam processing is the method delineated to the organic sector of the almond industry. While this is probably the cleanest method of pasteurizing almonds it is still an option reserved for those who have the budget to use machines like this.


As you can imagine, most organic almond farmers likely do not have the budget or the desire to invest in this type of equipment leaving their only option being contracting with other businesses that do have this type of equipment. Of course this is unrealistic because the farmers will have to transport their entire harvest from their farm, to the facility where this equipment resides (that could be anywhere in relation to where their almond farms are located) and then back to their farms before they can even prepare their harvest to be sold to their customers. The extra expenses this adds to the production of the almond crops eats a massive potion of the profit (if not all of it), making it a losing option for most producers and that is assuming they have access to this type of equipment, which most don’t.

On top of this unrealistic expectation on organic farmers as assumed by the USDA, the farmers are then left with almonds that have been heated to the point where their life force is almost entirely dissipated and with recent scientific studies showing that heating almonds creates potentially harmful levels of acrylamide, a threatening byproduct of the amino acid asparagine that results from heating almonds, organic almond farmers are basically left with a no win situation. This has been the fate of countless organic Californian almond growers who have been subjected, with no say whatsoever to the 2007 federal mandate dictating their immediate implementation of steam pasteurization.  

Due to how quickly this mandate occurred, most almond farmers were not able to comply, leaving them literally in the dust. Millions of dollars that once supported the thriving organic almond industry had now been averted into the hands of big corporate almond producers and pasteurization equipment producers.

The second primary almond pasteurization method is called propylene oxide fumigation(PPO).

PPO is the pasteurization method reserved for non-organic almonds. PPO is a chemical so nasty it was banned by both the American Motorcycle and the National Hot Rod Associations, where it had been used as a fuel before they recognized how dangerous it actually was. PPO is a verified carcinogen that is highly flammable with noxious fumes that are incredibly hazardous to a human beings personal health. Even the EPA has declared PPO a carcinogenic chemical that is responsible for neurological, gastrointestinal, respiratory, immune system dysfunctions and liver disease, to name a few.

In addition to the American Motorcycle and National Hot Rod Associations banning it, countries such as Mexico, Canada and the entire European Union have banned it because of its known carcinogenic risks to human beings!

Here is a hazard summary as reported by the EPA:

“Propylene oxide is used in the production of polyethers (the primary component of polyurethane foams) and propylene glycol.  Acute (short-term) exposure of humans and animals to propylene oxide has caused eye and respiratory tract irritation. Dermal contact, even with dilute solutions, has caused skin irritation and necrosis in humans. Propylene oxide is also a mild central nervous system (CNS) depressant in humans.  Inflammatory lesions of the nasal cavity, trachea, and lungs and neurological effects have been observed in animals chronically (long-term) exposed to propylene oxide by inhalation.  Propylene oxide has been observed to cause tumors at or near the site of administration in rodents, causing fore stomach tumors following ingestion via gavage (experimentally placing the chemical in the stomach) and nasal tumors after inhalation exposure.  EPA has classified propylene oxide as a Group B2, probable human carcinogen.”

Even if you are a person who cares less whether your US grown almonds are pasteurized or not, do not, I repeat DO NOT eat non-organic almonds grown on American soils unless you also don’t mind subjecting yourself to a chemical so toxic that its use was banned by National Motorcycle and Hot Rod Associations!



  1. Hello there! I could have sworn I’ve been to this blog before but after checking through some of
    the post I realized it’s new to me. Nonetheless, I’m
    definitely delighted I found it and I’ll be bookmarking and checking back frequently!

  2. Is it possible to grow almond conventionally (not certified organic) but remain unpasteurized? What are the differences between conventionally grown unpasteurized and organic almonds? Which kind has more nutritional value?


  3. i eat only organic nuts, and now i am about to order directly from you (thanks for the great article!) but i am wondering where you get the research that says steaming causes acrylamides? i have not found this information anywhere else, and am very curious.

    • Hi Lisa.
      Not sure where you found that info- What I found in one of our bogs is that roasting causes acrylamindes- here is the quote:
      Scientists have tested for possibly harmful levels of acrylamide, a threatening by-product produced from the amino acid asparagine, in roasted nuts such as Almonds and Hazelnuts. In addition, acrylamide is a chemical that can form in some foods during high-temperature cooking processes, such as frying, roasting, and baking.

  4. So I have been eating garbage for the last year? Makes me so mad. love your sight. thanks.

  5. Thank you!

    I also read that blanching and roasting takes care of the pasteurization issue. Is this correct?

    • This from the almond board:
      To date, FDA has approved oil roasting, dry roasting, blanching, steam processing and propylene oxide (PPO) processes as acceptable forms of pasteurization for almonds. Hope this helps!

  6. Hi Seth,

    Interesting tid bit on the pasteurization process of almonds. You mention the cost involved with pasteurization. Specifically, that most small organic farmers do have the financial ability to purchase pasteurization machines and therefore would need to truck their entire farm to a facility with the capacity to do this.

    So my question is this. How do the almonds get to your facility? From what I know they need to be shelled and not every organic farmer has the ability to own these shelling machines. Do you shell by hand? Or do the truck the almonds to a facility that shells and then send them elsewhere to be cleaned and then finally sent to the teams that package and distribute?

    Just looking for a little bit more info.

    Keep up the good work.

    • Jacob. We actually import our shelled almonds from Europe because all U.S. almonds are pasteurized by the methods previously stated. We do not believe almonds should be pasteurized and that pasteurized almonds are not raw. We know this has been a hardship on small farmers. The Cornucopia Institute has been on the front lines on educating people about this topic. Thanks for contacting us…

  7. How about drinks made with almonds?Do companies like SilkPureAlmond use the same kind of pasteurization methods?

    • Hi Katia,
      In response to your question. any U.S. handler of almonds (like manufacturing companies that process almonds) must either use pasteurized almonds grown in the U.S. or submit their own treatment plan to be approved by The almond board. The board only approves certain methods for pasteurization. So in essence their almonds are pasteurized- but may differ from the pasteurization methods on the growers side.

  8. Can anyone tell me what happens to the enzymes once the steam pasteurization has been done?

    • Our research shows that through pasteurization the shelled and hulled almonds are steam treated with temperatures up to 200 degrees. Not only does this high heat kill any pathogens that are present, it destroys the value content of the nut itself. Any time a food is heated above 115 degrees, vital enzymes are depleted.
      Thanks for your question

    • Cassie,
      Studies have suggested that enzymes are destroyed during the heating process

  9. Thanks for asking! Our almonds are from Europe where they do not pasteurize the nuts. Most almonds in the U.S. are pasteurized, unless you buy it directly from the farmer at a roadside stand (limited amount), according to the U.S. almond board. Additionally, all our nuts are certified organic too!

  10. Yes, that appears to be true…Thank you for your comment!

  11. Yes- that is why it is important to check the source for the food and to make sure it is certified organic.Thank you

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