Raw, gently cooked, air-dried sound good, but there can be important facts lurking in the lingo. Here are some good questions to ask...

Walk into any pet store today and you’ll see frozen pet foods with phrases like “raw”, “gently cooked,” or “minimally processed” splashed across the labels. These terms sound wholesome, but they can mean very different things depending on the manufacturer. For pet parents, understanding how these foods are made — and what that means for your dog’s nutrition and health — is key to making the right choice.

It’s important to know that all processing methods alter nutrient composition in food. Responsible manufacturers account for losses so the final food meets nutritional objectives.   Let’s break down some common “minimally processed” methods, how they work, and their pros and cons.

1. Sous Vide – the most common “gently cooked” method

How it works:

The entire recipe is assembled, sealed in a plastic bag and immersed in water, usually between 130 –190°F, for an extended time. The food gradually rises in temperature until the set point temperature is achieved.  It’s then removed, prepared for sale and frozen, or processed further – like with air-drying or freeze-drying.

Pros:

• Retains more vitamins, phytonutrients and antioxidants compared to high-heat methods.
• Depending on temperature, proteins denature, improving digestibility.
• Produces tender texture and even cooking.
• Depending on temperature, pathogenic and spoilage microorganisms are destroyed.

Cons:

• Long heating in plastic may leach plastic into food.
• Lower temperatures may not kill all pathogens.
• Food may dwell too long in the bacterial “danger zone” of 40° F – 140° F as it rises in temperature.  Bacteria in the danger zone multiply rapidly, increasing safety risks.
• If the temperature is too high or dwell time too long, proteins can oxidize – decreasing digestibility and creating inflammatory molecules and free radicals that damage fats.
• Fats are exposed to heat – causing reactions that result in rancidity.
• Vitamin loss in all ingredients often necessitates the use of synthetics or fortified ingredients.
• Enzymes are inactivated and beneficial microflora is destroyed.

2. Integrative – raw plus lightly steamed

How it works:

Select ingredients are individually steamed to unique ideal internal temperature by placing each one in a stainless steel (or other heat proof vessel) in a chamber. Steam surrounds the food, cooking it quickly and evenly. Ingredients are rapidly chilled and combined with cold raw ingredients like fish oil, sprouts, fruits, nuts and seeds.  The mixture is portioned, packaged for retail sale and frozen.  This is the way Goodness Gracious makes food.

Pros:

• In steamed ingredients, precise achievement of internal temperatures destroys pathogenic and spoilage microorganisms.
• Raw ingredients retain nutrients, enzymes, and microflora as a “living food.”
• Steamed ingredients (e.g. meats and veggies) retain more nutrients and moisture than high-heat methods. 
• Proteins denature – improving digestibility and bioavailability.
• Fats remain cold – avoiding rancidity.
• Phytonutrients and antioxidants in steamed veggies become more bioavailable.
• Gentle moist heat avoids browning or AGE formation compared to frying or baking.
• Prevents over-cooking and exposure to plastics.

Cons:

• Labor intensive; may result in a higher price point.

3. Light Baking

How it works:

Ingredients are combined, placed on racks or pans, and heated in an oven at temperatures that cause light browning. Food is portioned and packaged for sale and frozen.

Pros:

• Browning and water loss enhances flavor and aroma, boosting palatability for picky eaters.
• Kills food borne pathogens and spoilage microorganisms when safe internal temperatures are achieved.
• Simple, fast and cost-effective.

Cons:

• Browning forms inflammatory advanced glycation end products (AGEs) and reduces protein digestibility.
• Heating oil ingredients causes rancidity.
• Vitamin loss often necessitates the use of synthetics or fortified ingredients.
• Enzymes are inactivated and beneficial microflora is destroyed.
• Food may be packaged when still hot – leaching plastics into food. 

4. High Pressure Pasteurization – often used on “raw” or freeze-dried foods

How it works:

An increasing number of "raw" pet foods are processed using high pressure pasteurization (HPP) as a "kill step" for pathogenic bacteria.  HPP essentially cooks foods with pressure.  In HPP, all ingredients are sealed in a plastic bag which is then subjected to tremendous pressure (about 600 MPa) for a few minutes.  This is the pressure you would find 38 miles below sea-level – past the point in the Earth’s mantle where rock melts from pressure-driven adiabatic heat.  Food bags are then depressurized, packed for retail sale and frozen, or further processed into freeze dried food.  Some cooked pet food is also HPP’d. Read here to learn more.

Pros:

• Kills most pathogenic and spoilage microorganisms (though less effective for high-fat foods).
• Extends shelf life by irreversibly inactivating enzymes.
• Preserves most nutrients.

Cons:

• Beneficial microflora and enzymes are lost.
• Pressure oxidizes proteins and fats, creating free radicals, rancidity, and lowering protein digestibility.
• Foods are exposed to plastics.
• High fat foods may be cooked due to adiabatic heat.
• Spore-forming organisms can repopulate after processing, compromising food safety.
• Pressure can change texture of food.

5. Air Dried – may be HPP'd, baked or sous vide first 

How it works:

All ingredients are combined, placed on trays and put in a dehydrator.  The dehydrator contains mechanisms for regulating temperature, humidity and fan speed. A fan blows warm or hot air across the food removing the moisture.  The food going into the dehydrator may be pre-processed via sous vide, baking or HPP.  When the food is dry it is packaged for sale. 

Pros:

• By correctly using heat, humidity, and time pathogenic and spoilage microorganisms can be destroyed (though less effective for high fat foods).
• Creates a convenient shelf-stable food.

Cons:

• Nutrient bioavailability concerns as water is the biggest carrier for nutrients in the body.
• In order to create a food safe product, beneficial microflora and enzymes are lost.
• Depending on protocols and pre-processing, proteins can oxidize and fats may go rancid.
• Manufacturers often use a lot of salt to speed drying.
• Manufacturers may use glycerin to bind to water, creating a cheaper product.

Other Factors Beyond the Processing Method

While food processing methods influence nutrition, bioavailability and food safety, it’s only part of the equation. Macronutrient profiles; ingredient quality, sourcing and freshness; and transparency are important too.

Companies should share their full nutritional profiles, food safety protocols, and processing methods.  If those details aren’t available, ask.  If you don’t get an answer — or a good enough one – that is cause for concern.