Stop Looking For The Shortcut- Shelf Life and Challenge Studies ARE important!

As a food science consultant there are a few very common questions that I get asked all the time—the first one is—where can I find a co -packer! The second question following that is usually “how can I increase the shelf life of my product”

The potential clients asking this question usually do not know what the current shelf life is of the product, what causes the end of that products shelf life and they don’t know if the shelf life issue is bacterial, quality, or both!

This question usually comes up as it relates to dry packaged goods that are being sold at ambient temperature or “wet” items (soups, sauces, dressings) that are stored refrigerated. This does not apply to canned goods (which are sterile and shelf stable forever) or frozen items. Basically anything that has a potential end point needs to be “studied on the shelf”.

What is the driving force behind this desire to know a shelf life before the product has been manufactured, or sometimes even formulated? Usually it’s the supermarket chain insisting on a 9 month shelf life. Even if it’s a fresh baked good that is preservative free, the store mandates that it must last 9 months on the shelf. This puts the entrepreneur in a dilemma as they not only don’t know for sure how long their product lasts currently, and they don’t know how to extend the shelf life without using preservatives. They usually don’t want to use preservatives because more often than not there is a similar item on the shelf already that they are trying to match and improve on, but without preservatives (sound familiar!) . This competitor item probably has great attributes and lasts a long time (because they use preservatives) And you know how big competitor companies are, they will do anything to needlessly put preservatives into food because they secretly want to poison us and it’s up to the entrepreneur to solve that problem and make something even better that is preservative free and will be on the shelf five minutes after they created it in their mind.

(ok, a tiny bit of sarcasm there—just to make a point!)

Here are some bullet points to help the entrepreneur understand what is involved in extending the mysterious current shelf life of their not yet existing product that needs to be free of preservatives and last 9 months refrigerated or ambient.

1.    If you are making a baked good, the water activity will have to be very low, under .65 to ensure no mold growth. While this will keep your product mold free, it will be very dry and potentially have staling issues down the road.

2.    You can have a moist product with a higher Aw if you use natural preservatives. But you can’t just throw them into the product and hope for the best. A challenge study involving inoculating the product with bacteria and seeing if the food item can support its growth will tell you if that preservative is working. There are natural-ish preservatives on the market that can be labeled “cultured dextrose” or “natural flavor”.

3.    You can add more sugar (or sugar alcohol and allulose for the keto people) to keep that water activity low while maintaining some chewable texture.

4.    You can add more salt to lower that water activity as well. This mostly works with dried meat and jerky type items, not so much cake and cookies.

5.    For soups and sauces and wet items, assuming you don’t plan to pasteurize because you want to maintain flavor, freshness and emulsions (mayonnaises and dressings) then you have to assume that whatever goes in could contribute to your initial microbial load and without a kill step it may thrive in there! Make sure you use ingredients that are as clean as possible like pre -treated herbs and spices, dried spices pre-soaked in vinegar before adding it to the wet item. The lower the initial microbiological load, the longer it will last in the fridge!

6.    The product should be made in the cleanest most inspected and certified facility you can find. The cleaner the production run, the longer the product will last! Preservatives won’t protect you from dirty, contaminated manufacturing equipment.

7.    Using natural preservatives for wet items in conjunction with high acid (sub 4.6 for safety but sub 4.0 for spoilage) will also hold back yeast and mold growth. Acid alone is not enough to keep bacteria at bay.

8.    Speaking of acids- citric is an excellent pH reducer, but ascorbic is not. Ascorbic is vitamin C which can break down over time and stop being that pH reducer that it once was. Ascorbic is good for color retention though, another separate quality control issue that affects shelf life.

Remember that nothing lasts forever and 9 months is a long time for anything to be in the refrigerator or at room temperature. Even Hostess Twinkies .. yes TWINKIES only have a 3 month shelf life. Twinkies are often villainized as a highly preserved item that can last through a nuclear war, but they don’t. They get stale and go bad just like other baked goods.

Retail stores should not be so strict with their 9 month shelf life requirement as it fosters an environment that encourages us to eat really old muffins and cookies that are excessively dry or filled with salt and sugar.