Almond Pasteurization

In September 2007, the USDA began requiring that all almonds grown in California and sold as raw in the United States be sanitized via pasteurization. This decision was prompted by two outbreaks of Salmonella in the early 2000s that were traced back to conventional almond farms in California. In response to these outbreaks, the Almond…

Currently there are two main methods being used to pasteurize the almonds. One uses steam to sanitize the nuts, while the other uses the chemical propylene oxide, aka PPO, which is considered a possible carcinogen. Most conventional almond growers pasteurize their almonds using PPO. This includes Blue Diamond Growers (BDG), the main supplier of conventional bulk raw almonds for Natural Grocers by Vitamin Cottage. However, thanks to a special deal between BDG and Natural Grocers, all bulk raw almonds sold at Vitamin Cottage are steam pasteurized. So, while you may hear that BDG uses PPO to pasteurize their almonds, you can rest assured that any bulk almonds you buy at Natural Grocers are not treated with PPO and are, again, steam pasteurized.

Since pasteurizing with PPO is the standard in the industry and it is cheaper than pasteurizing with steam, many “natural” food manufacturers are presented with a dilemma: Do they purchase almonds that have been pasteurized with steam or with PPO to make their products (almond butters, snack bars, etc.)? In spite of early reports that steam pasteurization would be so costly that it would simply be prohibitive for many growers and buyers, this has not proved to be the case. In fact, most natural food manufacturers are now using steam-pasteurized almonds in their products, including the makers of all the jarred almond butters sold at Natural Grocers (Maranatha, Arrowhead Mills, Kettle, Justin’s, etc). That said, manufacturers are not required to indicate on their product whether steam-pasteurized or PPO-pasteurized almonds were used, so if you want to be completely sure as to which type of almonds are in the product, we strongly advise you contact the food manufacturer directly and ask them.

Note: There is one case in which you can be sure that the almonds in a product were not PPO pasteurized. If the product is USDA-certified organic, it cannot by law contain almonds that were treated with PPO (or any other synthetic chemicals).

Natural Grocers and PPO-Pasteurized Almonds

While all the bulk almonds sold at Natural Grocers are guaranteed to be steam pasteurized, there are some packaged products on our shelves that contain PPO-pasteurized almonds. One such product is Nut Thins, made by BDG. (The almonds used for BDG’s almond milk, Almond Breeze, are pasteurized via blanching and therefore do NOT contain PPO. This is also true of Bob’s Red Mill’s almond meal.) While this is regrettable, we cannot dictate what all our food manufacturers do. In addition, many manufacturers maintain that the extremely low amount of PPO on the nuts used in their product does not pose a significant health hazard. PPO-pasteurized almonds contain about 1/2500 of the lowest amount considered potentially dangerous.(1) At such levels, PPO can be considered no more or less hazardous than the other chemicals commonly found on conventionally grown almonds. (As anyone who buys conventional foods should know, most non-organic crops carry residues of the synthetic pesticides and insecticides they’re treated with.) In fact, some almond buyers claim that the minimal risk posed by trace amounts of PPO is worth the chemical’s impressive sanitizing effect. (PPO rids almonds not just of microbes but of insects and insect larvae as well.)

As for buying packaged products that may contain PPO-pasteurized, we leave this decision up to you. Again, if you want to know whether the almonds used in the product were PPO pasteurized, call the manufacturer. If you find PPO has been used and you disagree with this, let the manufacturer know. (If you’re a fan of Nut Thins and would like to encourage Blue Diamond to change its policy of using PPO-pasteurized almonds in that product, you can call BDG at 916-325-2839.)

Steam Pasteurization and the Raw

The FDA believes that since the “essential characteristics” of almonds are unchanged by pasteurization (whether by steam or PPO), it is acceptable to label pasteurized almonds as raw. The raw-food community disagrees, maintaining that exposing any food to a temperature above 118°F automatically disqualifies the food as raw. While Natural Grocers respects the opinion of both camps, we base our definition of raw on another criterion—whether the nut can be sprouted. In our opinion, sprouting is a sign of vitality and life. And since steam-pasteurized almonds can be sprouted, we consider it appropriate to label them as raw. So, while our raw bulk almonds have been steam-pasteurized, they will continue to be labeled “raw.”

A Final Word About Pasteurization

Many people believe that unpasteurized almonds are inherently better than pasteurized ones, even if the latter are sanitized using steam. Is this true? According to Wendy Larson—general manager of Big Tree Organics, a processing plant for a coop of organic almond growers in California—presently it is standard practice for organic almonds not to be washed at any point of their trip from orchard to store. As a result, raw organic almonds are loaded with yeast, mold, and insect larvae, not to mention possibly deadly bacteria. “There really does need to be a washing step,” opines Larson.

Like many growers, Big Tree has chosen to “wash” their almonds via steam pasteurization, which Larson equates to the almonds “getting a hot bath.” While temperatures of the surface of the nut may reach as high as 160°F, the inside of the nut is not heated nearly as much. In fact, preliminary studies funded by the ABC have reportedly shown no significant degradation of the almonds’ essential nutrients.


1. U.S. Environmental Protection Agency website: Integrated Risk Information System: Propylene oxide (CASRN 75-56-9) (4 May 2007), <>; “Almond Board of California Food Safety Document: Almond Pasteurization Using Propylene Oxide (PPO) Standard Operating Procedure (SOP),” Almond Board of California (Oct 2004).