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It’s not just the heat, it’s the acidity

Wed., Aug. 27, 2008

Botulism a concern when it comes to canning tomatoes

Poor tomatoes.

Of all the fruits and vegetables put into canning jars, none is more controversial. When new research in the late 1980s and early 1990s required the USDA to update recipes and canning instructions, tomatoes were hardest hit. Processing times were doubled in some cases and there were changes to most recipes.

Tomatoes are borderline when it comes to having enough acidity to inhibit the growth of botulism. Fruits contain enough natural acid that they can be processed in a water bath canner. Experts consider anything with a pH of 4.6 and below, such as fruits, to be safe for canning with a water bath. Anything with a pH above that – low-acid foods such as vegetables – must have acid added to them or they must be preserved using a pressure canner.

The acidity of tomatoes varies depending on how they’re grown and when they’re picked, but generally ranges from 4 to 4.6. To preserve them safely, lemon juice or citric acid must be added to whole, crushed or juiced tomatoes when processing. They can be processed in a boiling water bath or in a pressure canner to reduce the processing time.

Because the added acid affects the flavor of the tomatoes, many longtime canners have been resistant to change their canning methods.

“It will give a little bit of a lemon flavor, but it’s better than botulism,” Lizann Powers-Hammond told students during classes this spring and early summer for the Washington State University’s Master Food Preserver Program.

Picking a fight with botulism isn’t recommended. Outbreaks are rare, but they’re generally linked to home-canned foods. The neurotoxin is potent and can cause respiratory failure and death.

Throw out old recipes and recommendations and follow these instructions for canning tomatoes and salsa. Step-by-step instructions for water bath canning and pressure canning can be found in previous stories in our series online at www.spokesman review.com/food.

Prepare your tomatoes. Use underripe to ripe fruit. Don’t can overripe or decaying tomatoes. Do not can tomatoes from dead or frost-killed vines.

Wash the tomatoes in cool water and remove skins. Dip tomatoes in boiling water for 30 to 60 seconds or until skins split. Then, transfer to cool water. Skins should slip off. Remove cores.

Yield will vary, but in general here are the quantities it takes for each quart of canned tomatoes:

Crushed tomatoes – 2 3/4 pounds

Whole or halved tomatoes – 3 pounds

Tomato juice – 3 1/4 pounds

Tomato sauce – 5 to 6 1/2 pounds

Pack the jars. Tomatoes can be packed either raw or hot. To hot pack tomatoes, the fruit is packed in jars while still hot and then the cooking liquid is poured into the jars. For a raw pack, the tomatoes are packed into jars once they’ve been peeled and covered with boiling water or juice.

Hot packing has advantages. More tomatoes can be packed into jars because they are softer and tomatoes float less. However, raw pack tomatoes will be firmer.

Leave 1/2 inch of headspace between the food and the top of the jar. Use a bubble wand, chopstick or rubber spatula to release any bubbles and adjust headspace if necessary.

Add some acid. Before processing, lemon juice or citric acid should be added to the jars. Bottled lemon juice must be used to ensure a uniform acidity. Add 1 tablespoon per pint or 2 tablespoons per quart.

Citric acid also can be used. Add 1/4 teaspoon per pint or 1/2 teaspoon per quart.

Sugar may be added to mask a sour flavor. Extension publications recommend 1 teaspoon per pint and 2 teaspoons per quart.

Vinegar may also be used, but it is not recommended because it creates an undesirable flavor. Add 2 tablespoons per pint or 4 tablespoons per quart.

Salt can be omitted. Salt is only added for flavor, not preservation. To use salt, place 1/2 teaspoon to each pint jar, 1 teaspoon in each quart.

Follow the recipe. To safely preserve tomatoes the recipes and processing times must be followed exactly. Don’t add other vegetables to the canning jar because it changes the acidity, alters the processing times or could require a pressure canner for safe preservation.

Process tomatoes in boiling water bath or a pressure canner. Processing time depends on the size of the jars, how the tomatoes were prepared and whether they were packed hot or raw. Use a current book to find safe processing times: “Ball Blue Book,” the “Ball Complete Book of Home Canning” or “So Easy to Preserve” by the University of Georgia Cooperative Extension.

Processing times for some of the common methods of preparing tomatoes are below.

For a complete listing of processing times, the leaflet “Canning Tomatoes and Tomatoes Products” is available for $1 from area extension offices or online at www.extension.uidaho.edu/ youthfamilyhealth.asp. Click on “Food and Nutrition” to find it.

Or, there’s a link on the Fresh Sheet blog, spokesmanreview. com/blogs/freshsheet.

Processing times also are available online from the National Center for Home Food Preservation at www.uga.edu/nchfp.

Don’t improvise salsa recipes. Tested recipes must be used to ensure your salsa is safe. Cooperative extension offices offer recipes that have been tested in a laboratory for safety, and the books listed above have reliable recipes. There are only a few things that can be changed in a canned salsa without raising the risk for botulism. They include:

The type of tomato : Paste tomatoes, such as Romas, will produce thicker salsa. Slicing tomatoes will give you a thinner, more runny salsa. Green tomatoes or tomatillos can be substituted for tomatoes in any of the tested salsa recipes.

The acid : It is required for safety. Use only vinegar labeled 5 percent acidity. Store-bought lemon and lime juice can be substituted for vinegar in equal amounts.

The peppers : One type of pepper may be substituted for another to vary the flavor and heat intensity of salsas. Never increase the total amount of peppers in any recipe.

The spices : The amount of dry spices in a recipe can be altered. Cilantro, cumin and oregano can be left out for a milder flavor. For a stronger cilantro flavor, add fresh cilantro just before serving.

Don’t forget the basics. Follow the directions carefully and adjust for altitude. For step-by-step instructions for either water bath canning or pressure canning look in our previously published stories. They can be found online at spokesmanreview.com/ blogs/freshsheet.

Whole or Halved Tomatoes (packed in water)

From “So Easy To Preserve,” University of Georgia Cooperative Extension

13 pounds tomatoes (see note)

Wash tomatoes. Dip in boiling water for 30 to 60 seconds or until skins split; then dip in cold water. Slip off skins and remove cores. Leave whole or halve.

Add bottled lemon juice or citric acid to jars (see acidification directions above under “Add Some Acid.”) Add 1 teaspoon of salt per quart to the jars, if desired.

To raw pack the tomatoes, heat water, for packing tomatoes, to boiling. Fill hot jars with prepared raw tomatoes, leaving 1/2-inch headspace. Cover tomatoes in the jars with boiling water, leaving 1/2-inch headspace.

To hot pack tomatoes, put prepared tomatoes in a large saucepan and add enough water to completely cover them. Boil tomatoes gently for 5 minutes. Fill hot jars with hot tomatoes leaving 1/2-inch headspace. Add cooking liquid to the jars to cover the tomatoes, leaving 1/2-inch headspace.

Adjust lids and process in a boiling water bath canner. Process pints 40 minutes, and quarts for 45 minutes for elevations up to 1,000 feet. For 1,001 feet to 3,000 feet process pints for 45 minutes and quarts for 50 minutes. At 3,001 to 6,000 feet of elevation, process pints for 50 minutes and quarts for 55 minutes.

Acidification is still required for the pressure canning. To use a dial gauge pressure canner, process pints or quarts for 10 minutes at 11 pounds pressure for elevations up to 2,000 feet. For elevations of 2,001 to 4,000 feet, use 12 pounds pressure. At 4,001 to 6,000 feet of elevation, use 13 pounds pressure.

To use a weighted gauge canner, process pints and quarts for 15 minutes at 10 pounds pressure for elevations up to 1,000 feet. Above 1,000 feet use 15 pounds pressure.

Note: An average of 21 pounds is needed per canner load of 7 quarts; an average of 13 pounds is needed per canner load of 9 pints. A bushel weighs 53 pounds and yields 15 to 21 quarts, an average of 3 pounds per quart.

Yield: 9 pints

Approximate nutrition per 5-ounce serving: 31 calories, less than 1 gram fat, 1 gram protein, 7 grams carbohydrate, no cholesterol, 1.7 grams dietary fiber, 13 milligrams sodium.

Crushed Tomatoes

From “So Easy To Preserve,” University of Georgia Cooperative Extension

14 pounds tomatoes

Wash tomatoes and dip in boiling water for 30 to 60 seconds or until skins split. Then dip in cold water, slip off skins and remove cores. Trim off any bruised or discolored portions and quarter.

Heat one-sixth of the quarters quickly in a large pot, crushing them with a wooden mallet or spoon as they are added to the pot. This will exude juice.

Continue heating the tomatoes, stirring to prevent burning. Once the tomatoes are boiling, gradually add remaining quartered tomatoes, stirring constantly. These remaining tomatoes do not need to be crushed. They will soften with heating and stirring. Continue until all tomatoes are added.

Boil gently 5 minutes. Add bottled lemon juice or citric acid to jars (see acidification directions above under “Add Some Acid”).

Add 1 teaspoon of salt per quart to the jars, if desired. Fill jars immediately with hot tomatoes, leaving 1/2-inch headspace. Adjust lids and process in a boiling water bath canner. Process pints 35 minutes and quarts for 45 minutes for elevations up to 1,000 feet. For 1,001 feet to 3,000 feet process pints for 40 minutes and quarts for 50 minutes. At 3,001 to 6,000 feet of elevation, process pints for 45 minutes and quarts for 55 minutes.

Acidification is still required for the pressure canning. To use a dial gauge pressure canner, process pints or quarts for 15 minutes at 11 pounds pressure for elevations up to 2,000 feet. For elevations of 2,001 to 4,000 feet, use 12 pounds pressure. At 4,001 to 6,000 feet of elevation, use 13 pounds pressure.

To use a weighted gauge canner, process pints and quarts for 15 minutes at 10 pounds pressure for elevations up to 1,000 feet. Above 1,000 feet use 15 pounds pressure.

Note: An average of 22 pounds is needed per canner load of 7 quarts; an average of 14 fresh pounds is needed per canner load of 9 pints. A bushel weighs 53 pounds and yields 17 to 20 quarts of crushed tomatoes, an average of 2 3/4 pounds per quart.

Yield: 9 pints

Approximate nutrition per serving: 31 calories, less than 1 gram fat, 1 gram protein, 7 grams carbohydrate, no cholesterol, 1.7 grams dietary fiber, 13 milligrams sodium.

Stewed Tomatoes

From WSU Benton County Extension, “Tomatoes: How to Preserve Them Safely.”

2 quarts chopped tomatoes

1/4 cup chopped green peppers

1/4 cup chopped onions

2 teaspoons celery salt

2 teaspoons sugar

1/4 teaspoon salt

Combine all ingredients. Cover and cook 10 minutes, stirring occasionally to prevent sticking. Pour into hot jars, leaving 1-inch headspace. Remove air bubbles. Wipe jar rims. Adjust lids and process.

Process in a dial gauge pressure canner at 11 pounds pressure for elevations up to 2,000 feet. For elevations of 2001 to 4000 feet, process at 12 pounds pressure. At 4,001 to 6,000 feet, process at 13 pounds of pressure.

Yield: About 3 pint jars

Approximate nutrition per 2-ounce serving: 14 calories, less than 1 gram fat, .5 grams protein, 3 grams carbohydrate, no cholesterol, less than 1 gram dietary fiber, 141 milligrams sodium.

Chili Salsa

From Washington State University Extension, Benton County Extension

10 cups peeled, cored, chopped tomatoes

5 cups seeded, chopped long green peppers (see note)

1 cup seeded, chopped hot peppers (see note)

4 cups chopped onions

1 cup vinegar, lemon or lime juice

3 teaspoons salt

3 cloves garlic, minced

3 tablespoons cilantro, minced

1 teaspoon hot pepper sauce

Combine ingredients in a large saucepan. Heat to a boil and simmer 10 minutes.

Ladle hot sauce into pint jars, leaving 1/2 inch headspace. Adjust lids and process in a boiling water canner. Process for 15 minutes at altitudes 1,000 feet and lower. For altitudes of 1,001 to 6,000 feet process for 20 minutes. Above 6,000 feet process for 25 minutes.

Note: Use any variety of mild and hot peppers, not to exceed 6 cups total.

Yield: 7 to 9 pints

Approximate nutrition per 2-ounce serving: 19 calories, less than 1 gram fat, 1 gram protein, 4 grams carbohydrate, no cholesterol, 1 gram dietary fiber, 109 milligrams sodium.

Roasted Tomato-Chipotle Salsa

From the “Ball Complete Book of Home Preserving.”

12 dried chipotle chili peppers, stems removed

12 dried cascabel chili peppers, stems removed

2 cups hot water

3 pounds Italian plum tomatoes

3 large red bell peppers

2 small onions

1 head garlic, broken into cloves

2 teaspoons granulated sugar

1 teaspoon salt

1 cup white vinegar

In a large, dry skillet, over medium heat, working in batches, toast chipotle and cascabel chilies on both sides, about 30 seconds per side, until they release their aroma and are pliable. Transfer to a large glass or stainless steel bowl.

When all chilies have been toasted, add hot water. Weight chilies down with a bowl or a weight to ensure they remain submerged, and soak until softened, about 15 minutes. Working in batches, transfer chilies and soaking liquid to a blender or a food processor and puree until smooth. Set aside.

Meanwhile, under a broiler, roast tomatoes, peppers, onions and garlic, turning to roast all sides, until tomatoes and peppers are blistered, blackened and softened and onion and garlic are blackened in spots, about 15 minutes. Set onions and garlic aside until cool. Place tomatoes and peppers in paper bags. Secure openings and set aside until cool enough to handle, about 15 minutes. Peel and chop tomatoes, peppers, onions and garlic.

Prepare canner, jars and lids.

In a large stainless steel saucepan, combine reserved chili puree, roasted vegetables, sugar, salt and vinegar. Bring to a boil over medium-high heat, stirring constantly. Reduce heat and boil gently, stirring frequently, until slightly thickened, about 15 minutes.

Ladle hot salsa into hot jars, leaving 1/2 inch headspace. Remove air bubbles adjust headspace, if necessary, by adding hot salsa. Wipe rim. Center lid on jar. Screw band down until resistance is met, then increase to fingertip tight.

Place jars in canner, ensuring they are completely covered with water. Bring to a boil and process 8-ounce jars for 15 minutes and pint jars for 20 minutes. Remove canner lid. Wait 5 minutes, then remove jars, cool and store.

Yield: 8 (8-ounce) jars

Approximate nutrition per serving: Unable to calculate.

Tomatillo Salsa

From the “Ball Complete Book of Home Preserving.” Editors wrote, “The combination of tomatillos, chilies and cilantro creates a salsa with an authentic Mexican taste. In addition to making a great dip for corn chips, this salsa works well as a condiment for fajitas, burritos and quesadillas.”

5 1/2 cups chopped cored husked tomatillos

1 cup chopped onion

1 cup chopped seeded green chili peppers (see note)

1/2 cup white vinegar

4 tablespoons lime juice

4 cloves garlic, finely chopped

2 tablespoons finely chopped cilantro

2 teaspoons ground cumin

1/2 teaspoon salt

1/2 teaspoon hot pepper flakes

Prepare canner, jars and lids.

In a large stainless steel saucepan, combine all the ingredients. Bring to a boil over medium-high heat, stirring constantly. Reduce heat and boil gently, stirring frequently, for 10 minutes.

Ladle hot salsa into jars, leaving 1/2 inch headspace. Remove air bubbles and adjust headspace, if necessary, by adding hot salsa. Wipe rim. Center lid on jar. Screw band down until resistance is met, then increase to fingertip tight.

Place jars in canner, ensuring they are completely covered with water. Bring to a boil and process both 8-ounce and pint jars for 15 minutes. Remove canner lid. Wait 5 minutes, then remove jars, cool and store.

Yield: 4 (8-ounce) jars

Approximate nutrition per 2-ounce serving: 18 calories, less than 1 gram fat, 1 gram protein, 4 grams carbohydrate, no cholesterol, 1 gram dietary fiber, 54 milligrams sodium.



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