Monday, April 19, 2010

Home Canning Safety. A Little 101 for Beginners

Ready for a theme week? It's been a while! I decided we are going to have a little fun this week home canning some jams and fruit spreads. Our markets are overflowing with fresh berries and fruit around here and it sounded like so much fun. So, to kick off the week I wanted to share some vital information for those who may be home canning for the first time. It's my basic home canning safety 101. It's a little long in the tooth...but if you home can, it's well worth the read. In can save your life!

Can Home-Canned Food Spoil?
You've put up 50 pints of food from this year's garden: tomatoes, pickles, jam, chutney and a bumper crop of beans.But you still have rows of canned goods left from the last two seasons. How do you know they're still good? Can home-canned food spoil?

Yes, it can, and here are some reasons why, and what you can do about them:

Fresh food was of poor quality, or unwashed, unpeeled or untrimmed
This results in a high microbial load. It may have required a longer processing time for complete sterilization than is usually recommended.
Solution: Prepare food properly before canning.

Food was packed too tightly in jars
As a result, the temperature in the center of the jar did not get high enough long enough for complete sterilization of the food.
Solution: Pack food loosely; prepare according to the USDA Guidelines (1/2-inch slices, halves, etc.), then use the recommended time, pressure and temperature.

Jars became unsterile soon after being filled
If lids are not placed on jars and processing is not started right after jars are filled, microorganisms may grow to very high levels prior to processing.
Solution: Fill jars as quickly as possible and use sterile equipment.

This may be due to inaccurate heat-processing time or if processing was interrupted (by a power failure, pressure fluctuation, etc.).
Solution: Check to be sure you're using up-to-date processing times and watch closely to be sure processing isn't interrupted.

Open-kettle canning, microwave canning or oven canning methods were used
These methods do not get the canned food hot enough long enough to kill microorganisms. So the food may spoil, may contain dangerous microorganisms and their toxins, or both.
Solution: Use recommended canning methods: a pressure canner for low-acid foods and a boiling water bath canner for high-acid foods.

Improper cooling of jars after processing
Jars may have been left in the canner at the end of processing time or when the gauge read "O." As jars cool, they can suck water (containing microbes or spores) back into the food. Very slow or very rapid cooling may also have interfered with formation of a seal.
Solution: Remove jars from canner after processing to cool and protect from extreme temperatures.

Use of paraffin to seal jelly jars
Paraffin is no longer recommended for sealing jams, jellies or preserves. Mold, which is the most common spoiler of sweet spreads, can send "roots" down along the edge of the paraffin and produce toxic substances in the spread.
Solution: Can jams, jellies and preserves as you would other foods.

Improper storage
Home-canned foods that are exposed to temperatures over 95 degrees F may spoil. Microorganisms tolerate and will grow at high temperatures. So, if they are still present, they may grow and spoil the food, or alter the food so that other microorganisms can grow.

Home-canned foods stores in the sunlight may get very hot inside, which allows the air in the headspace to expand, breaking open the seal and allowing microorganisms to recontaminate the food.

If very acidic foods (pickled or fermented products, and some juices) were kept for a long time, the acid may have eaten away at the lid, resulting in pinholes that allowed microorganisms to get into the jar. Discard any home-canned food with damaged or flaking metal on the lid.

Lids on home-canned foods stored in a damp place may also rust through, allowing microbes to get into the food.
Solution: Store home-canned foods in a cool, dry place. Date all home-canned goods and use within a year.

For more information about food safety, call USDA's Meat and Poultry Hotline at 1-800-535-4555 .
A Fact Sheet for People Who Prepare Food - University of Maine Cooperative Extension, Bulletin #4277

Home canning Resources that I Recommend!
The Ball Blue Book, The Ball Home Canners Catalog, and home canning equipment and supplies are available from:

Alltrista Corporation
P.O. Box 2005
Muncie, IN 47307-0005

The Kerr Kitchen Cookbook, a home canning and freezing guide, is $3.50 plus 50 cents S&H, from:
Kerr Glass Mfg. Corp.
P.O. Box 76961
Los Angeles, CA 90076

A home canning and freezing guide is one of many federal publications available from:
Consumer Information Catalog
Pueblo, CO 81002
Bulletins available through your county extension office may be specifically revised for your geographic area. Look for ones on caring for pressure canners, canning tomatoes, vegetables, seafood, and fruits.
For miscellaneous questions about food preservation, check your phone book for your local County Extension office. Find out who your extension agent is, if they have any master food preservers registered, and what USDA pamphlets they stock. In some states smaller counties share agents. If this is the case with you, find the nearest county that has a staffed office, their office hours, and names of volunteers you can call for advice during off-hours. If you run into trouble on a hot Sunday afternoon, the expense of a long-distance phone call is nothing compared to the loss of a batch of food or the risk of food poisoning.

Some Common Question About Home Canning:
What is botulism?
Botulism is a serious, often fatal form of food poisoning. The poison is produced by "Clostridium botulinum", a bacterium that is found everywhere -- in soil, on raw fruits and vegetables and on meat and fish. Over the years, a number of people have died from botulism, as a direct result of improper home canning.
What causes botulism?
Botulism spores are resistant to heat -- even from boiling water -- and thrive in a moist, oxygen-free environment. As botulism spores reproduce, they generate one of the most extraordinarily powerful poisons on earth: one teaspoon-worth is sufficient to kill 100,000 people. Improper home canning creates the perfect environment in which to grow the botulism toxin. Because food contaminated by botulism may very well look and smell normal, there is often no warning. That is why home canning must be done properly with extreme care - any short cuts you take could be deadly.
What are the requirements for safe home canning?
Heat and acid level are the two keys to canning safety. High-acid foods such as plums or rhubarb are quite resistant to bacteria, and only require the "boiling water bath" method of canning. Low-acid foods -- including most vegetables, meats and seafood must be canned at higher temperatures, that only a pressure canner can attain.
What is the "boiling water bath" method?
The "boiling water bath" is probably what you saw your mother doing. It involves dropping a basket of sealed jars into a large pot of rapidly boiling water.
What is pressure canning?
A pressure canner is a large, cast-aluminum pot with a locking lid and a pressure gauge. By cooking under pressure, you can bring the temperature of boiling water up to 240F (116C). This is the minimum temperature necessary to destroy botulism spores, and the only way to guarantee safe canning for food items such as vegetables, meats and seafood. Your pressure canner should come with complete instructions. Always follow them carefully. Keep these pointers in mind:
Ten pounds is the minimum safe pressure;
Processing time -- will vary depending on the type of food being preserved and the size of the jar. Never shorten the cooking time that is recommended in the instructions.
If you live more than 1,000 feet above sea level, then both the pressure and cooking time will have to be adjusted (consult a chart);
Once the right pressure is reached during cooking, it must be kept constant throughout the cooking step;
Both "weighted" gauges and "dial" gauges should be checked for accuracy. Read the manufacturer's directions carefully for recommended testing/frequency procedures, to make sure your canner is being operated safely and correctly.
What jars are best for canning?
Manufacturers make heavy-duty jars specifically for home canning. Do not use, say, empty peanut butter jars, because commercial jars are not strong enough to be safely used for repeated home cannings. "Mason" jars -- which screw shut with a threaded neck are the most common choice.
Do not re-use the lids: after a lid has been pried off once, a perfect fit can no longer be guaranteed. The jars themselves can be used many times, as long as the sealing rims are perfectly smooth and there are no scratches or cracks.
What should you do if the home-canned food doesn't "look right"?
Never eat, or even taste any home-canned food that:
1. appears to be spoiled;
2. develops a bad smell during cooking;
the container has a bulging lid or is leaching;
3. you are not sure whether the food was properly canned or not.
4. Place any questionable containers and food in a waterproof container and throw it in the garbage.
5. Do not feed the questionable food to your pets or any other animals.
6. After throwing it away, wash your hands well with warm soapy water. Also wash any utensils or surfaces the food or container may have touched.
Basic Sanitation:
The importance of cleanliness
The other safety factor to keep in mind is cleanliness. All work surfaces should be kept clean during all stages of the canning process. The food being preserved must itself be rinsed clean. It is particularly important to sterilize the jars and seals before use.
To sterilize jars
Boil them for 10 minutes. If you live at higher elevations (over 1,000 feet) allow one more minute of boiling for each extra 1,000 feet of elevation. To sterilize tops (seals with rubber gaskets) boil them for five minutes.
Any questions?
Home canning is perfectly safe ... but it needs to be done correctly. We recommend that you read up on home canning before you try it. Good books are available on the subject, either at the library or in the stores. Pressure canners almost always come with comprehensive instructions. If you have an older pressure canner and cannot find the instructions, contact the manufacturer to ask for a copy.
Source: BC Health Guide
BC HealthFile #22, January 2002

So here are my thoughts on Food Born Illness and home canning... once you know what is safe, you are on your way!
Don't join the F.B.I. It could kill you. I don't mean the Feds. I am talking about food born illness. Here are a few things you need to know:

There are a few kinds of FBI's
Intoxication-- foods containing toxins produced during a pathogen's life. Once in the body, these toxins act as poison (see staphylococcus and botulism)
Infections-- Food eaten has a large number of living pathogens. These multiply in the body and usually attack the gastrointestinal lining (salmonellosis).
Chemical poisoning-- in home canning this can be caused by improper washing of fruits and vegetables if you buy commercially or raise your own. Use food grade or organic vegetables and fruits and wash them!! Dish soap is usually enough. You can't cook off a chemical poison, so even the proper heating and canning process won't get rid of this kind of FBI!
My biggest concerns:
Botulism--12-36-hr incubation period.
symptoms: sore throat, vomiting, blurred vision, cramps, difficulty breathing, central nervous system damage and possible paralysis. Fatality rate is 70%! Spores are hard to detect because they have no smell or flavor. The spores also have a high resistance to heat and need to be boiled 20-25 minutes to die. They can be found in soil. Wash your fruits and vegetables!!
Staphyloccous: 2-4 hour incubation period
symptoms: vomiting, cramps, diarrhea, nausea. Facultative bacteria found in nose, throat, and skin of infected humans. Toxins cannot be destroyed by heat! People infected with cuts, burns or respiratory illness should not handle food. Wear gloves, and don't home can when you feel sick. You may not know you have a staph infection!
Plant and animal poison: alkaloids and organic acids are a big concern. The most common in home canning is rhubarb leaves. remove them well and wash all surfaces.
Salmonellosis: 6-48 hr incubation period.
Symptoms: Headache, diarrhea, cramps, fever. It can be fatal or lead to arthritis, meningitis, and typhoid. This illness grows in the intestines of humans and can be killed at temperatures over 165 degrees. Boiling is 212 degrees! Eliminate all flies in you home before canning, wash hands and sanitize... even under fingernails! This especially applies after using the bathroom (and your kids need special attention for diapers while you are canning--eeek! Sanitize!!) Be sure when canning to not use utensils that have not come in contact with meat (unless pressure canning).
My biggest sanitation tips:
1- Use of a sanitation solution or a food grade kitchen sanitizer for all cutting surfaces (Lysol kitchen that says food safe).
2- It is important to have strict personal sanitation during canning sessions!
3- Keep jars and lids hot and sterile.
4- Keep your hair tied back.
5- Wear gloves and an apron that you don't take in the bathroom!
6-Cook only in Boiling (not just baby bubbles) water the full amount of time.
7- If you pressure can, follow the rules given by the manufacturer of your canner.
8- If your spouse or children help you with the canning-- mine do... Make sure they obey the sanitation rules and yes...
9-Have fun anyway!

There you Go!


Meadowlark said...

I just wanted to send some GLARING your way because you have fruits available. GRRRRRR. We can't even transplant anything until the first week of June. And the Farmer's Markets don't open til the 4th of July. :( SAD SAD SAD

Chef Tess said...

Tee Hee! I laughed so hard reading that! Sorry sweetie. I'm sure you can do some with frozen berries too...but seriously you'll be ready for canning season! Love ya!

Beverly@Beverly's Back Porch said...

Thanks for your post on home canning. I have canned, frozen and dehydrated for several years now. However when I returned to it after not canning for 10-15 years things had changed so much I took a class on home food processing that I'm sure saved many of my friends and family from sure death. I take a refresher course every three years. Anyone that is interested should call their local County Farm Agents office for more information. Thanks again.

Shae Ko said...

Question: we were given some canned apply pie filling that had just the sealed lids on top, but not the rims screwed on. What do you think. Are the rims that necessary?

Chef Tess said...

Excellent question Shae. After the initial setting period (I give mine 24 hours) without moving them, then the rims can be removed. I personally prefer taking the rims off to check the seals and be sure that it is well done. If there isn't any leakage or any evidence that they where canned improperly(foaming, discoloring, active bubbles or visible mold), I would say go ahead and use it. If you are worried about any FBI's boil the filling 15 minutes, or bake it in a pie (even better!).

Amy said...

So, how do you check the seal for leaks? I wondered this last year when I was doing all my canning. Is there a way to make sure it is 100% sealed?

(Very good info, btw!)

Jackie said...

I tried the orange marmalade recipe an it didn't work at all. I can't figure out how it could with only 3/4 cup of water. Mine came out like bitter orange sludge. In looking at other recipes it seems they all call for at least 4-8 cups of water. Am I missing something or is there somethingissinh from te recipe? I would like to try again but am afraid of making the same mistake. Thanks for your help.

Chef Tess said...

Jackie did you use sugar or sugar free sweetener? Did you let the peels and water sit out overnight? That's a great step for ensuring it doesn't end up bitter. How long did you cook the jam. It can be overcooked and that will make it end up too thick. The fruit I use is rather juicy as well.