Many types of people find canning an enjoyable and useful hobby. It preserves food that protects the hard work of gardeners so they can enjoy the fruit (and vegetables) of their labor all year round. It is also a useful skill for emergency preparedness, as properly preserved food can be eaten years later without the risk of bacteria, as long as it is not spoiled. Below, you’ll find a guide to food safety of your canned fruit and vegetables, including storage advice and how to inspect food for signs of spoilage before eating it.
Proper Storage for Preserved Foods
The average amount of time canned goods should be stored is between 12 and 18 months. However, there are many factors that affect freshness. Here’s a look at them:
Creating a Proper Seal
One of the most important things for canned good storage is creating a proper seal on the jar. While you can use cleaned jars, experts typically recommend that you buy new seal lids every time that you use a jar for canning. Metal breaks down over time and can create rust, which disrupts the pH balance of canned foods.
Storing in a Cool, Dark Environment
If you let your canned goods sit out in the sun or expose them to heat, it is going to change the composition of the jar. The materials may break down more and speed up the decay process. While this does not always mean that it will grow bacteria, it does mean that the food loses its freshness faster.
Before you store the goods, you should always label them clearly. Use a marker that is not going to wipe off easily. Write the name of the food, the date it was prepared, and the date it should be eaten by. Then, store the foods in a cool area with a temperature around 72-degrees Fahrenheit. Dark pantries or cellars are best for home canned goods.
Preparing the Fruit and Vegetables
To prepare your produce items, you should start by canning them when they are fresh. The heating process involved in canning causes fruit and vegetables to soften. If they are already over ripened, this can cause them to become unpleasantly mushy. Older vegetables are also less likely to be healthy.
Once you have picked the produce at peak ripeness, they should be properly cleaned and cut for canning. Wash foods using a solution of vinegar and water. Let them dry and any remaining odor from the vinegar wash will dissipate. Then, trim off any bad spots, roots, or other inedible parts. If you do not properly clean and trim the fruit and vegetables, it is more likely that the food will spoil because of an increased microbial load.
Another part of proper preparation is preparing a solution for canning. It is not uncommon for vegetables to be stored in salt water and fruit to be stored in simple syrup. There are different recipes for light, medium, and heavy syrup. There is also an option of adding other spices or mixing certain fruits or vegetables. However, you should always be sure the liquid and seasonings you use do not affect the pH balance too much.
Proper Processing of Home Canned Goods
Proper processing is also important. You cannot check the temperature or pH balance once the jars have been sealed. To prevent the spread of bacteria, you must have enough ‘headspace’ between the top of the jar and the level of the food. The headspace is different depending on what you are canning. It is also important to process the canned goods for the recommended amount of time—it is the high heat generated during the canning process that kills botulism bacteria.
Using recipe guides from reputable sources is a good way to learn more about the specifics of canning. You’ll learn how to adjust headspace depending on what you are canning and how to process the ingredients. There are two common methods—the hot water bath method and the pressure canning method. The method you use depends on what you are canning. You also have to prepare different solutions, since some foods are naturally more acidic foods. Foods with low acidity are more likely to be infected with botulism.
If you ever have questions about a recipe, look at the USDA website. The United States Department of Agriculture provides guidelines on canning. This includes a list of various fruit, vegetables and other preparations of home canned goods that describes the process that can be used for safe canning.
Something else that people sometimes forget to consider is the contents of the jar. If you overload a jar with fruit or vegetables, it will be harder for it to reach the proper temperature. Pack produce loosely to ensure all the ingredients become warm enough to kill botulism and other bacteria.
What Type of Canning Should I Use?
The two safe canning processes are hot water bath canning and pressure canning. Hot water bath canning involves placing the jars in a hot water bath. It is bets for high acid foods, including pie fillings, sauces, tomatoes, salsa, jellies and jams, relishes and pickles, vinegars, fruits, condiments, and fruit juices. Pressure canning is best for low-acid foods that are more susceptible to botulism, including certain salsas, chili, poultry, meats, vegetables, and seafood.
Testing the pH levels of canning liquid is the easiest way to know if you should use the hot water bath method or pressure canning. High-acid foods are those with a pH level of 4.6 or less. Anything with a pH greater than 4.6 should be processed using a pressure canner.
How Long Can I Store Home Canned Fruit and Vegetables?
The United States Department of Agriculture recommends all canned fruit and vegetables be consumed within one year after processing. This is the safest timeframe for avoiding bacteria, especially for low acidity food. Of course, foods have different shelf lives, depending on the acidity. Some guidelines recommend eating within 18 months. By properly preparing and storing foods, they will last longer.
Why Are Improperly Stored or Expired Canned Goods Unsafe?
When a canned good is exposed to air or becomes compromised, it can result in the foodborne illness botulism. Botulism thrives in conditions where there is no oxygen, low levels of acidity, and temperatures between 40 and 120 degrees Fahrenheit. This is the reason that canned goods are exposed to temperatures above 250 degrees when they are sealed in the jars. Any food and air inside are trapped once the jar is sterilized. As long as the seal remains intact, the food remains free from bacteria.
Botulism is incredibly dangerous. The symptoms begin between 12 and 36 hours after eating the bacteria, though the onset depends on how much of the toxin was eaten. The most common symptoms of botulism include:
- Dry mouth
- Difficulty speaking or swallowing
- Blurred or double vision
- Difficulty breathing
- Abdominal cramps, nausea, and vomiting
- Drooping eyelids
- Facial weakness on both sides of the face
If you experience these symptoms, it is important to seek medical intervention immediately. An antitoxin is generally injected to counteract the effects of the botulism bacteria on the nervous system. Without this toxin being deactivated, it can cause respiratory failure. Fortunately, the survival rate is very high in developed countries.
How Do I Know if Canned Goods are Spoiled?
Canning is meant as a type of preserving. It slows the rate that fruit and vegetables decay. The best way to know if a home canned item is spoiled is to inspect the jar. Since you cannot see, smell, or taste botulism, your best defense is inspecting the jar it is in. You should let the jar sit out for 12-24 hours before storing it in the pantry or cupboard. Then, press down on the center of the lid—it should not pop up or indent inward.
To be sure the canned goods are good when you take them out, you can also press down on the center of the lid. If there are any cracks or leaks, or if it looks like the lid is bulging, you should not eat the food inside the jar. There may also be obvious signs that the food is bad, including foam on the top of the food, spurting liquid when you open the jar, a bad odor, or the appearance of mold or discoloration. You should also avoid eating food that appears mushier or less fresh than when you canned it. If you are ever unsure, it is better to throw the food out than risk getting sick.
Canning fruit and vegetables at home has many benefits. However, to avoid exposure to dangerous botulism bacteria, it is important canned goods are stored safely. You should always be sure to label your canned goods clearly and eat them within 12-18 months of preserving. Being aware of the signs of damaged or contaminated food can also help you avoid eating dangerous bacteria.