Why Are California Almonds Fumigated with a Toxic Gas to Make Them 'Safe'?

Despite losing its food-additive status 29 years ago, the ‘probable’ carcinogen propylene oxide can still be used to fumigate these popular nuts.

By M.Verkerk, J.J.G.Claessens - Own work, CC BY-SA 2.5, https://commons.wikimedia.org/w/index.php?curid=938950

Is the forced treatment of California-grown almonds with a probable human carcinogen a public-safety measure or simply a bad regulation that puts consumers at risk and growers at a disadvantage?

Known as the “almond rule,” or, as a judge dubbed it, the “salmonella rule,” since 2007 it has mandated that almonds grown in California must be “pasteurized” –- that is, either steam-treated or gassed with the toxic fumigant propylene oxide (PPO) before being sold to U.S. consumers. Handlers, however, can ask for an exemption for almonds that receive further processing, such as roasting, blanching, or other heat treatments.

Since nearly all domestic almonds come from California’s fertile Central Valley area, that means that the “raw” almonds you buy in the supermarket, unless they were imported from abroad, have been pasteurized via one of these methods. Which method was used depends on the brand and the preference of the processor (except for organic almonds, which are always steam-treated). Farmers can also sell truly raw, untreated almonds in quantities of 100 pounds or less at farmers' markets and farm stands in California, and online.

The rule took raw-food advocates, for whom such almonds are a dietary staple, and other health-conscious consumers by surprise when it was first imposed. Almond growers, however, were outraged.

The following year, 15 growers sued the U.S. Department of Agriculture, stating the agency overstepped its authority in requiring California Central Valley growers to treat their almonds (something not required for imports or almonds grown in any other part of the U.S., for that matter). The case lingered on until a 2013 ruling ended the litigation in favor of the USDA, stating that the growers “waived their claims by failing to raise them during the rulemaking process.”

Highly nutritious raw almonds, according to a “friend” brief submitted during the lawsuit are “particularly important to a variety of groups, most notably ‘raw foodists’ and vegetarians,” and are acknowledged by many nutritionists to be healthier than cooked almonds.

The “almond rule” fiasco began with some California almonds that were found to be contaminated with salmonella in 2001 and 2004 – an “extremely rare” occurrence, according to experts. This led the California Almond Board to consider a mandatory rule requiring the pre-market treatment of almonds, a plan authorized soon afterward by the USDA.

Loopholes upon loopholes

Although the ruling caused California almond farmers to lose a lucrative market in raw almond sales and raw enthusiasts to lose easy access to a diet staple, it gave the average supermarket almond buyer something to be concerned about as well— the chemical “pasteurization” treatment itself.

That’s because PPO, a chemical also utilized in making polyurethane foams, antifreeze, and hydraulic fluid, is classified as a probable human carcinogen. And while the U.S. Environmental Protection Agency (EPA) currently allows the PPO treatment of almonds, nearly three decades ago the agency revoked the chemical’s “food additive regulation” status on the grounds that it “induces cancer in animals,” putting it in violation of the Delaney anti-cancer clause of the Federal Food, Drug & Cosmetic Act.

But that has not stopped the EPA from setting a residue tolerance for PPO when used as a fumigant on “raw agricultural commodities.” That loophole is explained simply as being a “separate provision,” one allowing a tolerance (the maximum amount allowed when the food is sold to consumers) to be 300 parts per million (ppm), a number first proposed in 1991.

Just a few years later, however, something very curious came about.

A petition submitted by Aberco, the manufacturer and sole U.S. registrant of PPO, requested that the tolerance be halved, all the way down to 150 ppm, to be “consistent with…public health considerations.”

And in 1996, the EPA did just that, but only for two years.

As a result, in 1998, the PPO tolerance doubled overnight. And even though California officials consider the fumigant to be a “known carcinogen,” growers in that state are free to release almonds for sale once levels of it are down to 300 ppm.

Although Canada does not allow PPO use on food products, that country had to play along with the regulation, citing “international trade obligations” and setting an approved residue level of 300 ppm in 2009 for imported California almonds. All other PPO-treated foods coming into Canada have a maximum residue limit of 0.1 ppm.

Except for organic almonds (that are steam-treated), whether the California almonds you consume have been treated with PPO or another method is up to the processor. Large retailers, such as Walmart or Whole Foods, can specify a choice for their private labels, but regardless of the process used the almonds will no longer be truly raw despite what the packaging may claim.

For that, you’ll have to find farms that sell actual raw almonds direct to consumers (labeled as “unpasteurized”) either online or at a farmstand, or buy raw almonds that are grown in another country –- options that are perfectly fine with the USDA.

Recalling that old Mounds/Almond Joy commercial, “Sometimes you feel like a nut, sometimes you don’t,” perhaps the explanation lies along similar lines: Sometimes the USDA thinks raw almonds are safe, sometimes they don’t.