Canning vegetables and fruits is a popular summertime activity for a lot of people, especially women in rural areas that have too much of one thing or the other grown in their gardens for their families to eat or for them to give away.

Whether it is jams, jellies, marmalades, pickles, soups, or almost anything else, if it can be canned, someone is probably doing it during the harvest season.

A similar process is used in the commercial canning industry, but the boon of doing your own canning from home is that you know exactly what is going into the jar you are putting your food in.

You have complete control over everything that goes inside and your exposure to pesticides and chemicals used on the foods in a canning factory is limited to what you use to protect your own garden from bugs and rodents.

Home canning also uses techniques that are tried and true to preserve food and prevent them from being contaminated by mold, yeast, and bacterias. Botulism and other diseases are caused by these contaminants and the canning techniques used to help prevent them are still in widespread use today.

What can you do to help prevent your home canned goods from spoiling after you can them..? And how do you know if they're spoiled after they've been on the shelf for a while..?

If you are a canner and have had some problems with spoiled or mold-contaminated jars in the past, then there are a few different things that could be causing your foods to spoil.

The first thing that you need to do is make sure that your fruits or vegetables (or whatever you are canning) is thoroughly washed and of good quality. They also usually require peeling if you want a quicker processing time.

If the food is packed too tight in the jars, then the temperature in the center of the jar does not get high enough for a long enough time to allow for the complete sterilization of what is inside. Pack food loosely in jars and use the time, pressure, and temperature required by the recipe.

Put the lids on the jars after filling them and immediately begin processing the food before any microorganisms can start to grow.

Once mold spores get into the jars, you'll have problems later on because a lot of times high temperatures simply do not kill mold spores, just like cold temperatures don't tend to. Use sterile equipment and jars.

Lastly, if you find mold growing in one of your jars after you open it, the best thing to do is toss it. Soft foods will become completely contaminated by mold, unlike hard blocks of cheese and other dense foods.