Let’s Get Let’s Get Ready to Ready to Preserve!Preserve!

Let’s Get Let’s Get Ready to Ready to Preserve!Preserve!

Barbara InghamBarbara Ingham

Extension Food ScientistExtension Food Scientist

www.foodsafety.wisc.eduwww.foodsafety.wisc.edu

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Today’s topics:Today’s topics:• Why preserve foods?Why preserve foods?• What are the basic food What are the basic food

preservation guidelines?preservation guidelines?• What resources are available What resources are available

to help you get started on a to help you get started on a successful food preservation successful food preservation season?season?

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Take a minute to Take a minute to consider…….consider…….

Why do we preserve Why do we preserve foods?foods?

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Why Preserve Why Preserve Foods?Foods?

• Increase the shelf life of food.Increase the shelf life of food.• Provide convenience.Provide convenience.• Retain the nutritional value.Retain the nutritional value.• Improve how food tastes.Improve how food tastes.• And because it’s fun!And because it’s fun!

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Freezing, Drying, Freezing, Drying, and Canningand Canning

…………Which method will Which method will you choose?you choose?

Our aim: safe, high Our aim: safe, high quality food.quality food.

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Food Preservation Food Preservation QuizQuiz

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Cold PreservationCold Preservation• Set refrigerators to 32° - 40°F• Set home freezers to 0°F or below• Rapid freezing is best (less damage)• Freezing Fruits & Vegetables (B3278)• Proper packaging is critical for quality• Storage of frozen foods

– Meats: 3 to 9 months– Fruits and vegetables: 1 year

Drying FoodsDrying Foods• Air drying for herbs; Sun drying

for fruits (ONLY!)• Controlled drying using an oven

or dehydrator is best• Resource: www.uga.edu/nchfp/• NEW! Recipes for making safe

Jerky coming in August 2009If water is not available, microbes can not grow

Heat ProcessingHeat Processing• BlanchingBlanching

– Short heating to stop enzymes, soften tissue, prevent color loss and remove air from tissue (vegetables before freezing/canning)

• PasteurizationPasteurization– Mild heat treatment designed to stop enzymes, to

destroy growing bacteria, and to kill yeast and molds (milk & juice, and pickles & jam too)

• CanningCanning– High heat to destroy harmful microbes (especially

pressure canning of meat, vegetables)

Two Types of CanningTwo Types of Canning• Boiling Water Canning

(212°F) – fruits and acid-added foods

• Pressure Canning (240°F or above) – meats and vegetables (dial gauge or weighted gauge canners)

• Remember…adjust for elevation!

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How do we know which canning method to

use?What is the pH (acidity) of the food?below pH 4.6 above

Boiling Water Fruits, Pickles, Salsa

PressureMeat, Vegetables

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What is ‘magic’ about pH 4.6?

• IF the pH of the food is above 4.6IF the pH of the food is above 4.6• IF there is no oxygen presentIF there is no oxygen present• IF the temperature is warmIF the temperature is warm Clostridium botulinum Clostridium botulinum can grow can grow

and produce TOXIN (botulism and produce TOXIN (botulism poisoning)poisoning)

‘‘Recipe’ for DangerRecipe’ for Danger1 Food, pH above 4.61 Vacuum sealed canning jar1 Room @ standard temperatureADD:C. botulinum sporesWAIT! You don’t need to add

these, they are everywhere!

Growing cells produce TOXIN

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Conditions for neurotoxin production:• Spores of C. botulinum• No oxygen• pH greater than 4.6

What does this mean What does this mean for home canning?for home canning?

Foods with pH above 4.6 that you want to can: Process in a pressure canner to destroy spores of C. botulinum.Adding pressure increases temperature

At sea level, water boils @ 212°F10 pounds pressure (psi) - 240°F15 pounds pressure (psi) - 250°F

Home Canning Home Canning ResourcesResources

• Using & Caring for a Pressure Canner(B2593)

• Wisconsin Safe Food Preservation Series (2008): canning fruits, salsa, vegetables, meat, tomatoes, pickles & jam (www.foodsafety.wisc.edu)

• Ball Blue Book www.freshpreserving.com/

• National Center for Home Food Preservation (www.uga.edu/nchfp/)

*Resources MUST be from 1994 or later!

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Botulism Strikes Spokane Mother, Two Children February 28, 2009

…The Associated Press reported that three people in Spokane, Washington, have become ill from botulism. The botulism apparently occurred from improper canning techniques used in home-canning of green beans vegetables from a private home garden.

The woman was a nurse in her 30s with two children under ten. She became ill enough to be put on a ventilator; the children suffered milder symptoms. The incident was linked to difficult economic times.

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What affects canning besides pH?

• Pack method – raw pack or hot pack

• Jar size – half-pints, pints or quarts

• Elevation - affects boiling point of water

Tomatoes, whole*Boiling water canner

– 85 minutesDial gauge canner -

25 min @ 11 psiWeighted gauge -

25 min @ 10 psi*hot pack, Qt. jars, 1,000 ft.p. 15 Tomatoes Tart & Tasty

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Tips for Successful Tips for Successful CanningCanning

• Properly pre-treat jars and lids• Fill jars with hot liquid (never cold!)

• Leave the proper headspace• Boiling water canning: jars covered

with 1-2 inches of boiling water at the start of processing

• Pressure canning: vent canner for 10 minutes before pressurizing

• Adjust for elevation

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Don’t harm your family Don’t harm your family with these canning with these canning methods!methods!

• Boiling water canning of low-acid food

• Open-kettle canning• Dishwasher canning• Oven canning

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Don’t Forget Don’t Forget

• Process at the correct temperature (boiling water or pressure canner)

• Follow an up-to-date, research tested recipe

• Adjust for elevation

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*Note: darker areas on the state map have an elevation above 1,000 feet. Increase time when boiling water canning; increase pressure when pressure canning.

And now a word And now a word about…canners vs about…canners vs

cookerscookersPressure canners and pressure cooker are NOT necessarily the same thing.•Pressure canners must hold at least 4 Quart jars and be able to regulate pressure at 5, 10, 15 pounds (psi).

Pressure cookers are NOT recommended for home canning.

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Will preserving food Will preserving food at home save you at home save you

money?money?• Do you have a ready supply of

fresh produce or meat?• Do you have canners and jars? • Do you have a working freezer

with plenty of space?• Do you have the time….?

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Food Preservation Updates

• Add acid to tomato products!• Adjust for elevation when canning• Just because it sealed….it doesn’t

mean it’s safe!!!!!!• Check pickle recipes for safety

(even refrigerator pickles)• Safety of steam canners• A word about vacuum sealers

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Getting Started…Getting Started…EquipmentEquipment

Assemble Boiling Water and Pressure Canners

Check dial gauges and rubber gaskets Dial gauges must be checked each

year! Inspect jars, rims & lidsPurchase freezer containersClean your dehydrator

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Getting Started…Getting Started…ProduceProduce

• Start with tested varieties• Harvest at the proper

stage of maturity• Discard diseased produce• Rapidly chill harvested

produce

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Getting Started…Getting Started…RecipesRecipes

•Use ONLY up-to-date, research-tested recipes!

•Don’t (necessarily) do what your Mother Don’t (necessarily) do what your Mother told you!told you!

•Current canning instructions Current canning instructions

date from 1994 or later.date from 1994 or later.•Time to leave creativity behind!Time to leave creativity behind!

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Canning and Canning and Preserving for Preserving for Special DietsSpecial Diets

• Choose recipes that don’t Choose recipes that don’t require sugar or salt for safetyrequire sugar or salt for safety

• Read the recipe carefullyRead the recipe carefully• Don’t choose your own Don’t choose your own

substitutionssubstitutions

see see www.uga.edu/nchfp/

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Happy Preserving!Happy Preserving!Happy Preserving!Happy Preserving!

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