Difference Between Steam, Dry Heat, & Chemical Pasteurization

Difference Between Steam, Dry Heat, & Chemical Pasteurization

Pasteurization is a process that is used on numerous products to increase food safety. Specifically, pasteurization kills pathogens that could cause food-borne illnesses. It is a necessary process for food production, whether you’re a large corporation or a small family farm; the FDA requires it on most foods, including almonds.

Almonds are the only nut that requires pasteurization, and there are different ways to treat them, each with its own advantages. Explore the difference between steam, dry heat, and chemical pasteurization to see how each affects the food you eat.


Steam pasteurization involves heating a food product to a certain temperature for a specific period. It is also called high-temperature short-time treatment and is a standard method used to pasteurize almonds. So, how does this work?

Supersaturation is an integral part of the process. Here, the steam produces condensation; water condenses onto the almonds. Then, machinery shakes the almonds to remove the moisture and, with it, pathogens. The shaking also ensures that all sides of almonds receive equal treatment. Essentially, the humidity kills pathogens that could otherwise cause illness.

Dry Heat

Dry heat or dry roasting is another FDA-approved method to make almonds safe for consumption. With dry heat pasteurization, there is no moisture involved. Instead, an oven raises the internal temperature of the food to a target temperature that kills pathogens. Once there, the oven holds the temperature for hours.

Dry roasted almonds also fall under the parameters of dry heat and meet FDA regulations.


Some farmers, including almond farmers, choose chemical pasteurization to eliminate bacteria and other pathogens. Steaming almonds can be an expensive and lengthy process. Still, some factories and small farmers choose to treat their almonds chemically.

The main method here is to fumigate the nuts with propylene oxide or PPO. There is some debate that steam and dry heat pasteurized almonds are healthier, but no study has proven anything conclusive.

Nonetheless, all three are FDA-acceptable ways to treat almonds to ensure they’re safe for us to eat! Knowing the difference between steam, dry heat, and chemical pasteurization gives you the ability to make more health-conscious decisions about the food you purchase.

To buy almonds online, check out Sohnrey Family Farms and be sure to explore all our products, such as beef jerky and dried fruits!

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