PPO Treated Almonds

PPO Treated Nuts

Say “No!” to Gassed Nuts

A Facebook post from Eva,  a dear high school friend, alerted me to the issue of PPO treated almonds. I asked Costco about it:

 Dear Carolyn,
 We appreciate you taking the time to email Costco Wholesale.
 Kirkland Signature Almonds are pasteurized by the Propylene Oxide 
 Fumigation process.
 Propylene Oxide (PPO) treatment: PPO is also a surface treatment which 
 has been approved for use on foods since 1958, 
 and is widely used for a variety of foods such as other nuts, cocoa powder 
 and spices. PPO is very effective at reducing harmful bacteria on almonds 
 and poses no risk to consumers. 
 In fact, PPO residue dissipates after treatment. 
 The effectiveness and safety of this process was revalidated in July 2006, 
 when PPO underwent a stringent re-registration process with the 
 environmental Protection Agency.
 The EPA confirmed that PPO poses no health risk.
 Thank you,
 Jason B.
 Member Service Center
 Costco Wholesale Corporation

After doing research on the subject, I’ve come to the following conclusion:

Treating almonds with PPO needlessly
exposes workers, consumers  and the environment
to a known hazardous substance.
Say no to PPO and choose organic almonds.

The Reason for Almond Pasteurization

In 2001 a few Canadians got sick from Salmonella after eating raw California almonds sold in bulk bins. To find the source of the contamination, authorities took samples at all of the farms that could have produced the nuts. Three different California orchards contained the bacteria. In response, the Almond Board of California researched how Salmonella outbreaks happen. They educated the industry on how to handle the product from farm to store safely. The California Department of Health Services implemented new sanitary procedures.

A second outbreak occurred in 2003. And then another in 2004. At least 29 people became ill. (As an aside, some of these almonds from Costco). The effort to educate and implement new practices had not ensured a safe product. They  recalled 15 million pounds of almonds (about 1.5% of the total harvest that year).

At first, the Almond Board of California initiated a voluntary treatment regimen; then on February 3, 2006, they unanimously approved going to the USDA and asking for a regulation that would require pasteurization. That rule came into effect September 1, 2007. Almonds from foreign countries are not required to be treated.  Raw almonds sold at road-side markets are exempt; almonds that are treated in other ways (blanching, roasting, etc.) are no longer “raw” and are also exempt.

The mandate occurred quickly.  Hardest hit were the smaller, family-owned almond farms that were facing a huge capital expense. Depending on the size of the farm, pasteurization equipment costs between $0.5 million to $3 million.  Millions of dollars that once went to family farmers were now going to pasteurization equipment or transportation to outsourced pasteurization facilities owned by big corporations.

About Proplyene Oxide (PPO)

PPO Ring

1,2-propylene oxide (AKA methyloxirane) is a highly volatile liquid that is incompatible with acids, bases, and a wide variety of other materials. It has a low boiling point a low flash point. Vapors form an explosive mixture with air.

Propylene oxide (PPO) does not occur in the natural environment and was first prepared in 1861. It is a colorless, highly reactive, liquid. Contact can cause blindness and death; pulmonary edema may recur up to two weeks after exposure.

Jason B. from Costco Service Center is correct that since 1958, propylene oxide is the only FDA/EPA authorized chemical for killing bacteria, mold and yeast in nut meats and cocoa powder. The residue tolerance set in 1958 is 300 parts per million (ppm). Incidentally, the National Hot Rod Association sets the tolerance at zero, banning it as a race car fuel due to its volatile and hazardous qualities. Their rules state:

National Hot Rod Association Rule regarding
Racing gasoline, gasoline, alcohol, gasohol, ethanol, diesel permitted. 
Nitromethane and propylene oxide prohibited.

PPO mutates DNA. And the wrong mutation in the right part of a gene can lead to cancer; or may even be an inheritable mutation.

  • The Summary Risk Assessment by the European Commission Joint Research Centre Institute for Health and Consumer Protection which states, “… it is not possible to identify a safe level of exposure at which there would be no risk to human health.”
  • The National Institute for Occupational Safety and Health writes: “When feasible, employers should substitute a less hazardous material for propylene oxide.”
  • Workers exposed to 12 ppm PPO for 2-20 years had reduced DNA synthesis and repair in lymphocytes. That’s not good. Those exposed for more than 20 years had a much higher rate of lymphocyte chromosome aberrations.

Because of these hazards,

  • Mexico bans its use as a fumigant.
  • Canada does not approve the use of PPO domestically. However, Canada does allow the import of PPO-treated almonds.
  • The European Union does not approve the use of PPO.

Benefits of PPO pasteurization method:

  • It kills bacteria.
  • It dissipates from the product before consumption
  • Almond growers can’t be blamed for Salmonella poisoning decreases risk of having to recall products
  • Long-term impacts on workers are nearly impossible to trace back

Costs / Risks of PPO pasteurization method:

  • Additional costs for producers. This affects smaller operations disproportionately.
  • Transportation of an extremely volatile liquid over 1,500 miles ((there are three primary producers of  PPO: Dow Chemical (plants in TX, and LA), Lyondell (plants in Texax) and Huntsman (Plant in Texas)) always brings some risk.
  • Workers are exposed to a known mutagen

In addition t0 the pasteurization process, the production of non-organic almonds includes the use of fungicides, pesticides and herbicides –  chemicals that may be linked to bee die-offs.

A Better Choice: Organic Almonds

In the steam pasteurization process used by organic producers, almonds are blasted with steam, then hot air for drying and finally cooled with chilled air.  While some in the natural foods community claim this harms the pecans’ quality and nutrition, the almonds still sprout – that is, their enzymes, are still functional. The fruit is still alive. The enzymes (proteins) are still functional so therefore the proteins haven’t been cooked.

I’ve not seen any evidence demonstrating the nutritional value in steam-processed nuts has changed. The vitamins and minerals and proteins are still there.

I agree they do look different. Looking closely in the bulk containers, I have noticed that treated raw almonds have a slightly different color to them. And they may not be as crunchy.

A Better Choice: Treat the Issue, not the Symptom

It is interesting to me that the first effort to stem the Salmonella outbreaks was research to figure out how outbreaks occur so that they can be prevented and  to educate the growers, handlers, and packagers on best practices for sanitary conditions.

I understand it’s a complex process with lots of variables, some of which are out of the industry’s control. For example, one of the outbreaks was at a bulk container at a store. Who knows whose hand was reaching around those raw almonds and now we all have to pay for it?

Prevention is the best medicine. Perhaps we can eliminate the need for pasteurization all together if we improve production, harvesting, processing, packaging and selling condition so that California’s almond growers can ensure a clean, sanitary environment during the entire process from tree to home.

A Better Choice: Give up Almonds

Unless you live in the Central Valley, it’ll be difficult to find sustainably grown 100% raw, organically grown almonds. These can only be found at local farmer’s markets. Shipping internationally is not sustainable.

Because it makes sense economically and environmentally for almond growers to increase water efficiency, support bee populations, and minimize pesticide use (and other expensive pest control techniques), they have improved production methods over the years.

However, almond production accounts for about 10% of California’s water usage.

In conclusion, if you’re going to continue to eat almonds, buy organic! It’s a vote for clean water, better wildlife habitat, and worker safety.

Resources – all accessed April 22, 2015

Almond Board of California (2008). Almond Action Plan – Pasteurization Treatments.  http://www.agmrc.org/medi/cms/March_2008__Pasteurization_treatmen_5C161B224773B.pdf

Canadian Food Inspection Agency. 2010-2011 Propylene Oxide in Foods. [online]. Published 2014-11-13. http://www.inspection.gc.ca/food/chemical-residues-microbiology/chemical-residues/propylene-oxide/eng/1351917937884/1351918123486

Chemical Book (2010) Propylene oxide. http://www.chemicalbook.com/ChemicalProductProperty_EN_CB9854235.htm

Dow Chemical Company (2014). Propylene Oxide – Technical Data Sheet. http://www.dow.com/propyleneoxide/info/

United States Environmental Protection Agency (2006). Reregistration Eligibility Decision for Propylene Oxide. United States Environmental Protection Agency.EPA/738/R-06/029. Prevention, Pesticides and Toxic Substances. Washington, DC.

72 FR 62 (2007). Almonds Grown in California; Outgoing Quality Control Requirements, Federal Register; Final rule. http://www.gpo.gov/fdsys/pkg/FR-2007-03-30/pdf/07-1557.pdf

Institute for Health and Consumer Protection European Chemicals Bureau (2002). Methyloxirane (propylene oxide). European Commission Joint Research Centre. Special Publication 1.02.129.

National Hot Rod Association (2014). NHRA Champion Drag Racing Rulebook. http://www.nhra.com/ebooks/2014_NHRA_Rulebook/pubData/Source/2014_NHRA_Rulebook.pdf

National Institute for Occupational Safety and Health (NIOSH) (1987). Carcinogenic Effects of Exposure to Propylene Oxide. Cincinnati, OH: U.S. Department of Health and Human Services, Publication 89-111.e.

Pero RW, Bryngelsson T, Widegren B, Hogstedt B, Welinder H (1982). A reduced capacity for unscheduled DNA synthesis in lymphocytes from individuals exposed to propylene oxide and ethylene oxide. Mutat Res 104:193-200.

6 Comments on “PPO Treated Almonds

  1. Please Don’t Overlook this. We will never rid Raw Almonds of PPO until we the people speak out.

    I have started a petition here to put an end to it. I do not have friends who will sign this, so I must revert to asking bloggers who agree with me. I believe if we can get 5+ signatures, the petition will be viewable to others on change.org

    Please Help me put a stop to this! The Petition URL is below!


    • Most likely, the raw organic almonds used in this product are steam pasteurized. One concern is that heat oxidizes the omega-3 fatty acids present in almonds. At best it’d make the fatty acids rancid; at worst, the process releases free radicals which, due to their high reactivity, are linked to damage within cells associated with a range of disorders such as cancer, Alzheimer’s, diabetes, atherosclerosis and arthritis. One of the reasons people push green leafy vegetables, vitamin C, etc. is because these foods provide antioxidants which neutralize free radicals.


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