food preservation

So, You Want to Preserve Your Famous Salsa…

By Diane Wright Hirsch, MPH, RD

Extension Educator/Food Safety

canning tomatoesEvery year, about this time, I am spending time on the phone, talking people out of canning. Well, not exactly. I strongly encourage canning as a way to preserve summer tomatoes, peaches, apples and cucumbers (often as pickles). But, invariably I will answer the phone and on the other end of the line is someone who wants to can their FAMOUS salsa recipe (or pickles, or pesto, or peppers in oil). While I could write volumes on “What Not to Can”, salsa is the subject of this article.

The word “salsa” is the Spanish word for sauce. The Encyclopedia of American Food & Drink reports that the first mention of the term “salsa” appeared in print in the U.S. in 1962. As of 1991, they said, sales of salsa surpassed ketchup.

The origins of these sauces may be Aztec, when the traditional ingredients included tomatoes and chili peppers. But the creative cook can easily find recipes using a variety of ingredients such as beans, mangos, pineapple, grilled corn, avocado, or peaches. Historically, “salsa” was considered an uncooked sauce (salsa fresco or salsa cruda). But, in the interest of convenience, salsa is now most often processed in glass jars and found on the supermarket shelf next to taco shells, tortillas and refried beans (or in plastic tubs in the produce section).

Making and canning salsa in a commercial processing operation is one thing. Doing it at home is another.

Most salsa recipes are a mixture of low-acid foods (such as onions and peppers), with more acid foods (such as tomatoes). Often, there are additional acid ingredients that may include vinegar and citrus juices such as lemon, lime, or orange.

The types and amounts of ingredients used in salsa, as well as the preparation method, are important considerations in how a salsa is canned. Generally, acid foods (tomatoes, fruits) are safely canned in a boiling water bath canner. So folks may think that a tomato or fruit based salsa would also be safely canned in a water bath canner. However, once you add low-acid ingredients such as onions, peppers, black beans, corn, cilantro or avocado, the pH (measure of acidity) balance may be tipped to the low-acid side. At this point, the pH is likely at 4.6 or higher and the only safe way to can the product is in a pressure canner (to safely can in a water bath canner the product pH must be below 4.6).

If a salsa has enough low acid ingredients to render the final product, “low acid” by definition, then you run the risk of having a salsa that will support the production of deadly toxin by the Clostridium botulinum bacteria. Improperly canned salsas or other tomato-pepper combinations have been implicated in more than one outbreak of botulism poisoning. Follow these considerations for safe salsa:

Choose and use safe ingredients

The acid ingredients help preserve canned salsas and make them safe for water bath canning. Most often bottled vinegar or bottled lemon juice is used. Use only commercial and bottled products. An equal amount of bottled lemon juice may be substituted for vinegar in recipes, but do not substitute vinegar for lemon juice. This substitution will result in a less acid and potentially unsafe canned salsa. If the product is to “acidic” or tart for your taste, add a bit of sugar to offset. Do NOT cut down on the acid!

Tomatoes and/or fruit ingredients should be just ripe, free of cuts, rot, or mold. Do not reduce the quantity in the recipe. Overripe tomatoes may be too low in acid for safety. If green mangoes are called for in the recipe, do not use ripe mangos as they also may be too low in acid for safety.

Peppers, onions, and other low acid ingredients must also be added in amounts given in the recipe. An extra pepper might just throw you into the low acid realm…measure and count carefully.

Spices such as cumin, dried oregano, salt and pepper can be adjusted to taste. However, fresh herbs such as cilantro (a low acid ingredient) should be added according to the recipe. You can always add the fresh herbs just before serving for the freshest flavor.

Choose and use a safe recipe

The USDA/Extension mantra has always been, “Only use tested, science-based home-canning recipes from reliable sources like the National Center for Home Food Preservation and some equipment or home preserving ingredient manufacturers.” This is especially true for any acidified food like salsa or pickles. Then, follow the directions, ingredient list, and amounts listed in the recipe. Never add flour, cornstarch or other thickeners—this will have an effect on the processing time needed to heat the interior product to a safe temperature. Store opened salsa in the refrigerator once opened.

If you want to stick with a personal favorite recipe, there are two things you can do. Can a basic salsa and add additional ingredients (beans, corn, avocado) just before serving. Or, make your FAMOUS salsa and store it in the refrigerator for up to one week or freeze it for up to one year. Freezing will certainly affect the texture of your fresh salsa, so test out a small portion first to see if you like it.

For more information about making and preserving salsa, go to (National Center for Home Food Preservation). On that site you will find the fact sheet (some of the information in this article was from this fact sheet), Canning Your Own Salsa Recipe.

Fermentation of Vegetables at Home

Fermentation of Vegetables at Home, A Food Preservation Workshop To Be Provided By UConn Extension 

making sauerkraut
Photo: Diane Wright Hirsch

Fermentation is one of the oldest methods of food preservation. All over the world it is used for the creation and the preservation of food, including beer, wine, sauerkraut, kimchi, sour pickles, grains, yogurt, etc.

UConn Extension is offering a fermentation workshop, where participants will learn the principles of fermentation and how it is used to create sauerkraut and kimchi. This is a hands on workshop, so participation numbers will be limited.

The program will be held Saturday, September 17th at the New Haven County Extension Center, 305 Skiff Street, North Haven, CT,  06473 from 9:30 am to 1:00 pm.

The course fee will be $20.00. Pre-registration is required due to limited space, please register early. Registration deadline is Monday, September 12.

For more information, contact Diane Hirsch (, 203-407-3163). Program and registration information is posted on the UConn Extension food safety web site at:

Fermentation: Preservation with Benefits

By: Diane Wright Hirsch, MPH, RD

Senior Extension Educator – Food Safety

making sauerkraut
Photo: Diane Wright Hirsch

Believe it or not, winter is coming. This is a good time to think about preserving some of the vegetables that you may find in your cold cellar or at the fall farmers’ market. Cabbage, of course, but really, that is just the beginning. Consider adding cauliflower, carrots, cucumbers, and daikon radishes…just about any vegetable can be fermented.

Fermentation as a food preservation method has a very long history, perhaps as long as 12,000 years. Cheese, yogurt, sauerkraut, kimchee, olives, salami, jerky, and bread; also, beverages such as hard cider, wine, beer, and coffee were all produced by the fermentation process. Some fermented foods have been critical to the food culture of a country or region. Think yogurt in the Middle East, sauerkraut (a source of vitamin C in the winter) in Germany and fermented sausages in Italy.

Years and years of food preservation via fermentation have resulted in the development of safe and effective methods for processing these foods. According to Dr. Fred Breidt, Jr., a USDA microbiologist who specializes in the safety of fermented and acidic foods, the scientific literature has never recorded a case of food poisoning from raw vegetables that have been fermented properly. Please note the key word, properly!

How does fermentation create a safe food product?

During fermentation, lactic acid bacteria consume the sugars or carbohydrates in the food, producing acid and flavor compounds. When fermenting foods at home, we rely on creating the environment needed for a safe and effective ferment. To allow for the growth of the desirable lactic acid bacteria, the process needs sufficient water (added or generated from the vegetable after salting), nutrients (the vegetable provides these), an appropriate amount of salt, and the absence of oxygen/air. The beginner should use tested recipes that are science based, provide the appropriate salt concentration and amounts of vegetable and, if needed, added water.

The beneficial bacteria and the lactic acid they produce in the fermentation process compete for and destroy the pathogens that can cause foodborne illness. This is not to say that you do not have to use safe food handling procedures when making sauerkraut or kimchi at home. Starting with ingredients that are contaminated with pathogens, or cross contaminated by dirty hands or work surfaces may result in a product that can’t be made safe by fermentation.

So, start with vegetables grown using safe practices—using properly composted manure or plant compost; safe water for irrigation; harvested with clean utensils and clean hands. Wash vegetables thoroughly before cutting them. Make sure all knives, cutting surfaces and hands are washed before preparing the vegetables.

Achieving a good ferment—using sauerkraut at the example.

Start with the freshest cabbage you can. That is not to say that cabbage that has been stored awhile is not useable. You may have to add water to older veggies if you cannot generate enough after salting and pounding or squeezing the cabbage.

Speaking of salt. The type of salt you use is important. Do not use any salt that is iodized. In fact you really want to use pure salt, without any anti-caking additives. Pickling salt is the best for fermentation properties. If pickling salt is not available, kosher salt may be a possible substitute. However, it is best if you measure the salt by weight rather than by volume—a tablespoon of kosher salt is actually lighter than pickling salt because it is flaked. You will need a larger volume of kosher salt, but the weight would be the same.

Do not mess with the amount of salt in the recipe that is usually given as a ratio based on the weight of the cabbage (i.e. three tablespoons of pickling salt for each 5 pounds of shredded cabbage). So, again, using a kitchen scale will yield a more accurate measurement and over time, you can standardize your process based on the weight of your ingredients.

The container used for fermenting your cabbage should be large enough to accommodate your cabbage. Generally allow a gallon for each 5 pounds of cabbage. Use a fermenting crock made of food-grade ceramics or stone, a glass container or food grade plastic. Clean with hot soapy water and rinse with very hot water before use. You will also need a weight to hold the cabbage under the brine while fermenting. You can purchase fermenting weights or simply weigh the cabbage down with a plate, held down with two or three glass jars filled with water or a large food-grade plastic bag (I use a turkey brining bag) filled with brine, in case it leaks into the product. The brine should be made of 3 quarts of water with 4.5 tablespoons of pickling salt.

Once your cabbage is shredded, salted, pounded (with your clean fist or maybe a potato masher) to release the liquid so that it covers the cabbage, cover with the weight to keep the cabbage under the brine. Place a clean towel over the whole thing to keep insects out.

Your fermentation container should be kept at a temperature of about 68-75 ºF. This is one reason I wait until later in the fall to make sauerkraut. My basement gets cooler then, making a good fermentation room. If it is too warm, fermentation may progress too quickly to spoilage. If too cool, the process will take longer.

Once the fermentation process begins, it will progress through three stages, as long as the temperature is desirable. First, Leuconostoc mesenteroides initiates sauerkraut fermentation. It produces carbon dioxide, effectively replacing the oxygen in the jar. This takes 2-3 days. Next, Lactobacillus plantarum and Lactobacillus cucumeris continue the ferment for about 10-30 days (temperature dependent). Finally, Lactobacillus brevis finish off the process, usually in less than a week. When you notice that there are no more bubbles at the side of your crock or jar, then the fermentation is complete.

Expect the whole process to take about 3-4 weeks. Check often to be sure there is no mold. Skim it off as soon as you see it. If allowed to remain, the mold can contaminate the whole batch and result in a waste of a lot of good cabbage.

After about 3 weeks, start to taste your sauerkraut. When it reaches the desired “tanginess”, remove from the crock and store in the refrigerator, covered in brine (you may have to add a bit of water), for as long as 4-6 months. Sauerkraut can also be canned in a water bath canner, but the process will destroy the microorganisms that are thought to benefit your intestinal health.

For information on growing cabbage in the home garden, contact the Home and Garden Education Center at or 1-877-486-6271. For more information on fermentation and canning sauerkraut, go to the National Center for Home Food Preservation at

Is Home Vacuum Packaging a Safe Way to Preserve Food?

By: Diane Wright Hirsch, Extension Educator/Food Safety


Photo: Minnesota Extension

Whether you are someone who wants to store away a cache of food in case of an emergency or weather disaster or if you simply want to preserve some green beans from your garden or freeze some chicken from the farmers’ market, you may have considered purchasing a vacuum packaging machine, or maybe you already own one.

Along with the quest for more information on preserving food at home SAFELY, Connecticut food preservers are also on the look out for ways of preserving food more effectively and easily. At the same time interest has piqued in the use of vacuum packaging devices made for use in the home kitchen. So what about these little machines? Are they a good addition to the food preservation toolbox?

What is vacuum packaging?

When you use a vacuum packaging device, you are removing the air from the package of food. This air contains oxygen; which is needed by some microorganisms in order to survive and multiply. By removing the oxygen, you will limit the growth of these “aerobic” organisms that can include bacteria and fungi that cause food spoilage and foodborne illness.

In addition, the oxygen in a package can promote certain reactions that can spoil foods. This might include causing a food to become rancid or to darken in color. Both of these reactions are a type of “oxidation” that will be minimized if oxygen is removed from the package.

But, don’t run out and purchase a vacuum packaging device until you also know the disadvantages to packaging this way.

Vacuum packaging can be expensive. The machinery can cost well over $100. In addition, you must then purchase special bags, which are not reusable.

There are some new hand-held devices that may be battery operated or a simple manual pump that resembles a bicycle tire pump. These are much cheaper and users report that they are effective and easy to use. However, these bags are also not reusable.

If you decide to go ahead (you might argue, “hey, it will save me from throwing away food that becomes inedible in my freezer”), there are a few more things to think about.

There is a risk for botulism or other bugs that actually like an oxygen free environment—and they will not tell you when they are there!

When spoilage organisms are present, they are certainly more than willing to let you know. They cause a food to look peculiar, they might make a food slimy or smelly or turn funny colors. This is good. Then we know to throw the food out. But, the biggest fear we food safety types have regarding the use of vacuum packaging equipment in the home is that some pathogenic or disease causing bacteria also prefer the anaerobic (oxygen free) vacuum packaging environment.

One of these is the Clostridium botulinum—the organism that causes botulism poisoning. These bacteria may give the consumer no sign that they are growing in a vacuum packed food. The food can look, smell and taste perfectly fine. Botulism is most likely to result from low-acid, moist foods canned or vacuum packaged in an air-free environment. Think chili in a can, mushroom soup or smoked seafood. Also, think low acid veggies or meats vacuum-sealed on your kitchen table.

So, can these machines be used safely?

Vacuum packaging machines will extend the storage time of refrigerated food, dry foods, and frozen foods. However vacuum packing machines or sealers are NOT a substitute for heat processing of home canned foods.

Perishable foods packed in a vacuum package must be refrigerated between 34 and 38°F or frozen at 0° F. They cannot be safely stored at room temperature. Keep in mind also that when you defrost foods frozen in vacuum bags, additional precautions must be taken. I like to recommend that people open the package, allowing some air to enter when removed from the freezer. Then defrost in the refrigerator. Thawed, unopened vacuum-packaged foods are a recipe for a food borne illness disaster—maybe even botulism poisoning.

Dry foods such as crackers or rice can be stored in vacuum bags safely at room temperature. You can also use them for dehydrated foods including dried fruit or tomatoes, nuts, or meat jerky. These foods contain little moisture to support the growth of bacteria. But it might be cheaper to simply use glass jars or plastic or metal containers with air tight lids that can be used over and over again.

Also, keep in mind that any foodborne illness causing bacteria that might have been present on something like raw chicken or unwashed blueberries will still be there when these vacuum packaged frozen or refrigerated foods are prepared for eating. Be sure to handle them as you would any perishables. Wash fruits and vegetables before eating or preparing, use good cleaning and sanitation practices, and cook raw meat, poultry and fish thoroughly before eating.

For more information about vacuum packaging food for home storage, go to the National Center for Home Food Preservation at or contact the Home and Garden Education Center at or 1-877-486-6271.

Save Summer Flavor: Freeze Fruits and Vegetables

blueberries-MNHow to save summer flavor for winter: freezing fruits and vegetables

By Diane Wright Hirsch

UConn Extension Educator/Food Safety


It has been a wonderful year for growing fruits and vegetables in Connecticut. A trip to your backyard vegetable garden, local farmers’ market or maybe the nearby pick-your-own orchard, even late in the season, will attest to this: bins and shelves are still overflowing with beautiful tomatoes, raspberries, green beans and corn. But, soon it will all be gone and we will be wishing that we had stashed some away for the long winter.


There is a way to fix this–without turning to imports from China or Chile or even the well-traveled produce from California, which begins to lose nutritional value as soon as it is picked. Freeze your local produce, whether it is from your garden or the farmer down the road. If done right, freezing can preserve the flavor and health-giving benefits of summer fresh fruits and vegetables. IF DONE RIGHT.


Freezing is easy, requires no special equipment and is often the home food preservation method of choice. Many people do not want to use a canner or pressure canner. It can be a little scary if you do not know what you are doing. Keep in mind, though, that freezing can be a more costly way of preserving than canning. It requires that you have a freezer that can hold all of the food you want to freeze at 0°F and, if you choose single use plastic freezer bags, they can be expensive. But, it is less time consuming and most folks prefer the flavor and texture of frozen foods.


Another thing to keep in mind is that you may not be able to reproduce the commercially frozen products that you are used to. Unless you have a blast freezer in the basement! The frozen foods you buy in the grocery store is often picked and processed the same day. This is always best, though not always possible when you are waiting for your garden to produce enough green beans to make the job worth it. Also, they are freezing food very fast at very low temperatures that create very small crystals and prevent mushiness and texture changes that may occur during home freezing.


Freezing produce at home

You can’t just wash your produce, cut it up and throw it in the freezer without much thought. Well you can, but the result will be just as tasteless as a January tomato. People need to know that while the temperature of a freezer keeps food safe, it will not preserve the quality of your produce without some help.


After harvest, fruits and vegetables undergo chemical changes which can cause spoilage and deterioration of the product. This is why these products should be frozen as soon after harvest as possible and at their peak degree of ripeness. Fresh produce contains chemical compounds called enzymes which can cause flavor, color and texture changes, and the loss of vitamins and minerals even while stored in the freezer. These enzymes must be inactivated to prevent these reactions.


When freezing vegetables, you can inactivate the enzymes by blanching—or dropping them into boiling water or steaming for a short time. Cool the vegetable quickly in ice water to keep it from cooking. Even though blanching can be a bother, in most cases it is absolutely essential for producing quality frozen vegetables. The exceptions to this rule are peppers, onions and herbs, which do not need to be blanched.


Fruits are a bit different. The major problem associated with enzymes in fruits is the development of brown colors and loss of vitamin C. Because fruits are usually served raw, they cannot be blanched like vegetables. Instead, home food preservers control the browning and loss of vitamins with ascorbic acid (vitamin C), an anti-oxidant. Ascorbic acid may be used in its pure form or in commercial mixtures (such as “Fruit Fresh”). This is more effective than the use of lemon juice.


Often you will see recipes that suggest that you freeze fruits with sugar or in a light sugar syrup. Though many folks today are sugar phobic, keep in mind that the quality of many fruits (peaches, apples) is not as good when packed without sugar. Sugar helps to preserve both the flavor and texture of frozen fruits. If you are planning to use the fruits to make jams or preserves later on, or, if there are health concerns such as diabetes, then, of course, freeze in plain water or dry.


Frozen fruits and vegetables can also suffer a variety of changes—flavor and texture—when the product is not well protected from the air. You might have heard it referred to as freezer burn. You can control this problem by using materials for packaging that are made specifically for the freezer—plastic wraps, plastic bags, hard sided plastic containers or even glass. You should not consider this an opportunity to re-use plastic containers that may have once held cottage cheese, yogurt or other non-frozen foods. Economically and environmentally speaking, you may want to invest in re-usable freezer containers that may be found in grocery, farm supply or department stores next to the home canning supplies. Glass works well, too, but special care must be taken to avoid breakage, including leaving enough space for the food to expand while freezing.


Keep in mind also that while freezing preserves safety and quality, there are some foods that will simply be different after you freeze them. Some fruits and vegetables are naturally high in moisture. When frozen, the moisture freezes and causes the cells of the plant to burst. Once thawed, these products will be softer than when fresh—no matter how careful you are. So, tomatoes, many fruits, summer squash and greens once frozen will be better suited to mixed dishes, sauces or soups. It doesn’t make much sense to freeze cabbage (develops off flavors), celery, cucumbers, endive, lettuce, or radishes.


Frozen fruits and vegetables will maintain good quality for one year if packed well and kept in a freezer at 0°F.


Freezing Green or Yellow Beans

Pick young tender beans that snap when broken. Harvest while seeds are small and tender. Wash, snip off tips and sort for size. Cut or break into suitable pieces or freeze small beans whole. Blanch 3½ minutes. Chill in ice water. Drain, pack in freezer container.



Choose well ripened fruit of good quality. Wash in cold water and sort. Dip 3 or 4 peaches into boiling water until skins loosen—15-20 seconds. Peel and slice peaches into containers one-third full of syrup (3 cups sugar to 1 quart water with 1⁄2 teaspoon ascorbic acid). Make sure to leave a head-space of at least ½ inch to allow for expansion of the liquid during freezing.

5 Tips for a Successful Home Canning Season

Photo: PSU Extension
  1. Start with a research-tested recipe. Just because a recipe is in print, doesn’t mean it’s safe for you and your family. Start with a recipe that has been tested to make sure that the product is safe and high quality. A great place to begin is with the recipes from the National Center for Home Food Preservation Some states, such as Wisconsin, have recipe books that have been developed to ensure safe canning no matter where you live in the state:
  2. Use recipes that are up to date. We all want to continue with those tried-and-true recipes, but canning recommendations have changed dramatically over the last 15 years. If you are using recipes that date before 1994, then it’s a good idea to set those aside and find an up-to-date recipe that has been tested for safety.
  3. Start with equipment in good working order. A boiling water canner should have a flat bottom, so that it fits nicely on the stove top, and a tight-fitting lid. A pressure canner will have either a dial- gauge or a weighted gauge. Dial gauge canners should be tested every year for accuracy. Most county extension offices will test dial gauge canners for free! (This is certainly true in Wisconsin.) If you have a Presto dial gauge canner, contact the company if your county extension office does not offer this serve – 715-839-2232. Replace canner gaskets every 2-3 years. At this time, a steam canners is not recommended as a replacement for a boiling water canner. There is information to help you successful use your pressure canner: Using Pressure Canners one final note on canners, don’t use a pressure cooker, sometimes called a pressure saucepan, as a pressure canner. A pressure canner holds a minimum of 4-quart jars and has a pressure regulator capable of measuring up to 15 pounds of pressure.
  4. Assemble jars and other items. Use only standard home canning jars, not old mayonnaise jars, and check these to make sure they are not chipped or cracked. Always use 2-piece lids; purchase lids new each year (the sealing compound will break down on storage) and sort through screw bands to make sure they are not rusted. It’s fine to reuse canning jars, as long as they are not chipped or cracked. Garage sales can be great places to locate used canning jars, just make sure they were designed for canning. Other items that come in handy for home canning include jar fillers, tongs, and lid wands.
  5. Leave your creativity behind! Home canning is one area where being creative can lead to food safety disasters. So begin with an up-to-date, research-tested recipe and carefully follow the directions. Don’t make ingredient substitutions, unless they are allowed, and follow the recipe directions through all the steps. Don’t substitute dishwasher canning, oven canning, or open-kettle canning for an approved canning method – boiling water canning or pressure canning.

And remember, at the end of the day, a sealed canning jar does not indicate that the food inside is safe. A sealed jar simply means that the jar is sealed. You can do a lot of things wrong and still get a jar to seal! Follow these easy steps for safely preserving your garden’s bounty to enjoy all year round.

B. Ingham, May 2011, Wisconsin Extension

For additional information visit USDA’s National Center for Home Food Preservation.