Years ago, it was a way of life, food was grown in a home garden, then preserved for use through the winter. With the modern food chain in place now, that aspect is often forgotten. Food that is purchased is already preserved for the most part. Whether you purchase food that is in a bag, a can, a jar, or from the freezer department, the preservation work has been done for you, you just need to put in the correct storage place. However, after seeing the bare shelves during Covid, many developed a realization of just how delicate the food chain can be.
Whether you are looking for a way to preserve the bounty from your garden, to preserve a great deal you found at the farmer's market, or you just want to learn some of the food preservation methods to supplement your pantry. It would be beneficial to know the Three Goals of Food Preservation, to help you understand which preservation method would work best for you.
Photo credit: Seonaid Criosdail
Plums
I wanted to have a little fun with this blog. Even though we are discussing a serious topic of food preservation, I requested photos from a food preservation group of which I am a member. The members there shared some wonderful photos of their food preservation endeavors. All of the photos used in this blog were sent to me from members of that group. These are a witness to the variety of foods that can be safely and successfully preserved, and allows them the show off a bit of their hard work with preservation!
So, now for topic of the day, the Three Goals of Food Preservation. When we preserve food, whether it be by canning, freezing, dehydrating or freeze drying, we are basically wanting to do these three things:
1. Prevention of contamination of food from damaging agents.
2. Delay or prevention of growth of micro-organisms in the food.
3. Delay of enzymatic spoilage.
(The last two are strongly related and will be discussed together later)
For storing or preserving food, we have to remove the ideal living conditions for micro-organism that lead to food spoilage. Like humans, microorganisms need a source of food and water, and they also need a suitable pH and temperature to grow, so food preservation techniques aim to target these requirements. Safe food preservation uses procedures which effectively manage the microbial content of foods and processes that alter or delay the activities of enzymes in the food. The techniques may be applied separately or in combination. The goals are to prevent contamination in the first place, to remove or reduce the numbers of contaminants, and to prevent microbial growth.
We will go over each goal, and explain how to reach it.
Photo credit: Stacy Greene
Peaches
1. Prevention of contamination of food from damaging agents.
When preparing food for preserving, it is important to keep the food clean. Always maintain a clean work area, wash your hands, and use a clean cutting board and knife.
While preparing food for long term or shorter term preservation, regardless of the method, always choose ripe, healthy specimens. Food with blemishes such as rusty green beans, mushy tomatoes, or moldy cucumbers will not preserve well and will not taste as good either. Foods with blemishes can be trimmed and used for immediate cooking or eating, but not for preserving.
If you are canning the food you are preserving, always use clean jars, pots, spoons, and etc. Contamination can happen from a dirty spoon used to stir the food, or a dirty funnel used to fill the jars. This is especially the case with foods that will be water bath canned.
If you have to leave the food preparation area, it is always a good idea to wash your hands when you return to prevent any contamination picked up elsewhere. Let's be honest, we all try to keep a clean house, but it doesn't take much to contaminate food, especially if you have pets or children in the home.
Photo credit: Pamela Lee
Photo credit: Melissa Taylor
Canned Cinnamon Pickles & Squash for freezing
2. Delay or prevention of growth of micro-organisms in the food.
3. Delay of enzymatic spoilage.
These are separate goals, that can be reached using the same techniques, so I am going to cover them together.
There are a few ways to delay or prevent the growth of micro-organisms in the food you are preserving and delay the spoilage due to naturally occurring enzymes.
Most tested safe food preservation methods will have instructions on how to prepare the food for the method you are using. For example: the blanching of vegetables prior to canning, freezing or drying helps to remove soil, insects and microorganisms, and destroys or slows the action of enzymes. It also sets the color and generally facilitates dicing, peeling and packing.
If you are going to be freezing your vegetables, you need to realize that most high water content vegetables will have a better quality if they are blanched beforehand. This is especially true if you are going to use the vegetable by itself in a side dish such as green beans, or peas. Although freezing is a great way to preserve food, it must be understood that freezing doesn't prevent the growth of micro-organisms, it just delays the process.
Photo credit: Kalynn Rhoades
Tomatoes
Photo credit: Hilarie Dunlapp Greene
Tomato Soup
Another way to prevent the growth of micro-organisms is to can the food in jars. If the food has a low acid content (or a high pH value) then pressure canning is recommended. The extreme high heat created within the pressure canner is capable of killing any micro-organisms in the food such as the botulinum toxin. However, there are times when blanching is needed before the food can be preserved with canning. Many vegetables, like potatoes and other root vegetables, have a naturally occurring enzyme that needs to be halted before the food can be safely canned. This requires the food to be blanched. If the food is not blanched, then the enzymatic action within the food can still cause spoilage. If the food has a high acid content (or a low pH value) then a water bath canning method will do the trick. Many micro-organisms cannot thrive in an acidic environment, however, it is important to process the food as recommended to remove the oxygen from the jars. Oxygen contains many unseen contaminants that can lead to spoilage even in an acidic environment.
I have often found that, unless the food will yield an unpleasant texture, canning is the preferred way to offer long term, shelf-stable food preservation.
For short term food preservation, the most common method used is refrigeration. This is an effective way to delay the growth of those micro-organisms. However, just ask anyone who has pulled out a food storage container of mystery leftovers, it does not prevent the growth of those pesky micro-organisms. It's always advisable to keep tabs of what is stored in the refrigerator. Sometimes, food seems to spoil super fast in the fridge, this is most likely due to micro-organisms already thriving in the food before you even get it home. Some food, especially fruits, store better if they are washed and kept in an air-tight container in the refrigerator.
Photo credit: Ann Reidt Knapp
Photo credit: Phyllis Pope Clayton
Pears
Photo credit: Daniele Rousseau
A variety of tomato items:
pickled, juice, stewed, chutney and paste
Dehydrating is another great method of long term preservation that can inactivate destructive enzymes, although it does not destroy spores contained in the food. It is important to maintain a clean environment when prepping food for dehydration. There are many foods that are successfully preserved with dehydrating such as: beef jerky, vegetables, and fruits. It is important to consider how the dehydrated food will be used after storage. Often foods that are rehydrated after storage do not have an appealing texture when eaten alone, however, when mixed in with soups or casseroles, the once dehydrated food just needs some time to soak up the moisture that was drawn out during the dehydration process.
Photo credit: Katie Schritter Curtis
Photo credit: Sara Shaffer Price
Photo credit: Gail Allen
Once you understand the "why" of food preservation, it will be easier to learn the "how". Every step in the food preservation process has a reason, and although many rebel food preservation enthusiasts do not see the need in following procedures, they would produce a much better finished product if they just understood the "why'.
Food preservation can be an extremely rewarding hobby. Seeing a bounty of food from the garden processed and preserved on the shelf, or in the freezer for future use, and not worrying about it spoiling on the counter, can be a great feeling of accomplishment. Knowing you have produced a safely preserved food product to feed your family is beyond satisfying!
If you have not yet tried your hand at food preservation, but would like to try, let me share some places to get started.
I have other blog topics on the Home Page that covers Water Bath Canning 101, Pressure Canning 101, as well as some simple beginner recipes for canning.
The National Center for Home Food Preservation has a wealth of information about different types of food preservation. It is simple to navigate too! Simply use the search at the top and enter what you are looking for. A variety of related topics will show for you to choose from! https://nchfp.uga.edu/
The University of Georgia Extension Office not only has a website, they also have a "So Easy to Preserve" book! check it out here! https://extension.uga.edu/topic-areas/food-health/food-preservation.html
Your local Extension Office will have regional information that is relevant to where you live. If you do not know where your local Extension Office is located, visit here: https://www.uaex.uada.edu/about-extension/united-states-extension-offices.aspx
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