How To Make A Food Product Shelf Stable (2024)

There are three kinds of food products in this world—the shelf stable kind that sits on the shelf for several months or the refrigerated kind that usually tastes better, tastes fresher and has all kinds of bright colors and perceived health benefits that are retained because the product has been minimally processed, and the frozen kind- which can last for months!

It would be great if all products could be manufactured and sold in the refrigerated and/or frozen section of the supermarket but due to the high cost of placing the product in that space, cold transportation and the need to move the product quickly (refrigerated products have a short shelf life) many new gourmet specialty food producers have to go down the shelf stable path in order to make ensure that their is a profit (and not a loss).

Specialty food producers are often disappointed when they realize that they have to do some severe processing to their gourmet food product in order to make it shelf stable. Here are a few of those severe methods that can have a serious effect on the flavor and texture of the product.

Dry/Low Water Activity—Water activity is the amount of “available” water in a food system. In order for a product to be stable and not support yeast and mold growth it has to have a very low water activity of around .65 (water activity is measured by using a water activity unit sold in the USA by Aqualab.com). For example, you may have a delicious moist energy bar that is chewy and soft but the water activity may be around .75 and the bar will only last a few days on the shelf at room temperature before yeast and mold start growing on it. So you have to essentially lower the water activity. This is done via dehydration, adding more salt, or adding more sugar. This is why products like beef jerky, raisins and jams and freeze dried fruits can last such a long time. The water has been tied up with salt, sugar or just simply sucked completely out of the product. Keep in mind that a product can be shelf stable at a higher water activity but preservatives (often not wanted by clean label artisan food makers) would have to be added.

Retort-A retorted food product is essentially a “canned”food. Products that are canned are basically cooked to about 250’F and are made commercially sterile. A can of food can last forever on the shelf. Canned meat, canned stews, canned green beans—those are all retorted. Of late you an also get flexible pouch retorted products (like those pouches of tuna fish) but they are still retort style heat treated. So if you developed an amazing chicken soup and want it to be shelf stable, you may have to retort/sterilize it if you want it to last on the shelf and it may not taste as great as what you made in the kitchen.

Acid or Acidified- Acidified foods are products that use a combination of heat and acid to generate shelf stability. For example, apple sauce is naturally acidic (pH below 4.6) and may be subjected to a heat treatment of around 195F. In this case, the acidity is a bacterial inhibitor so it is not necessary to cook it AS hot as the retorted samples. These types of products are usually tangy and sour and include fruit purees, juices and other shelf stable pasteurized products.

It really boils down to this-- pH ,moisture and heat are the natural ways one can make their product shelf stable. The severity of these processes can sometimes be reduced by using preservatives. The better tasting products are the fresh refrigerated ones but they have a short shelf life. Its all about picking and choosing your poison really!

It’s important to think about shelf stability and how to achieve it when you are developing your specialty food product. Many entrepreneurs don’t consider the processing conditions that will have to take place to take their concept from the kitchen to the room temperature supermarket shelf.

For more details on food production you can read my assorted blogs and articles at www.theintrepidculinologist.com