Food Preservation Food Preservation WorkshopWorkshopJuly 11, 2009July 11, 2009

Pat Sleiter & Tammy Schulte, Extension Master Food PreserversBridget Mouchon, Extension Family Living Agent

Today’s TopicsToday’s TopicsWhy Preserve Food?

Basic guidelines for food preservation.

Resources available to help home food preservers, like you and me.

Why preserve foods?Why preserve foods?Increase the shelf life of food.ConvenienceNutritional valueImprove tasteFeel good about it coming from

locally grown produce or home garden

Save money on foodIT’S FUN!!

Canning, Freezing, & Canning, Freezing, & DryingDrying

OUR AIM:

Safe, high quality foods.

Fight Food SpoilageFight Food SpoilagePrevent mold, yeast, and

bacteria from growing on your food.

Prevent bruising and wilting.Prevent changes in flavor and

texture, to the best of our ability.

Microbial Spoilage: Microbial Spoilage: Factors under our Factors under our control!control!

Food (provides nutrients microbes need)Acidity (microbes like low-acid, near neutral

pH environments)Time (microbes need time to grow; we can

heat foods to kill bacteria for the correct length of time)

Temperature (Microbes like 40-140°F)Oxygen (Most microbes like oxygen and can’t

live without it; however, the bacteria that causes Botulism only lives in the absence of oxygen)

Moisture (Microbes like to be moist, need water to live)

Controlling MicrobesControlling MicrobesDrying/salting/sugaring:

◦All of these make water unavailable or less available to microbes.

◦Salt and sugar both bind water and make it unavailable or less available to the microbes

Acidifying:◦Adding acids such as vinegar or citric

acid can create an unpleasant environment for microbes and extend shelf life.

Controlling Microbes: Controlling Microbes: FreezingFreezingWhile refrigeration at 33-40°F slows the

growth of microbes, and makes foods last longer freezing stops their growth altogether

Deep quick freezes help keep cell structure of meats and vegetables intact and maintains better food texture and flavor. Blanching of some kinds of vegetables and sugaring of fruits also helps with this.

Controlling Microbes: Controlling Microbes: CanningCanningCanning combines multiple

techniques, depending on the food and the recipe.

Removes oxygen and seals jars.High heat kills microbes.

Canning continued: Canning continued: Preventing botulism Preventing botulism poisoningpoisoning

Clostridium botulinum spores grow in the soil and are present in fruits and vegetables.

These spores can only come alive in anaerobic or oxygen-free environments (i.e. inside a sealed jar)

Once alive, the spores produce the deadly toxin which causes botulism poisoning

2 methods to ensure safety:If using hot water bath, must can a high acid

product, like pickles, fruit, and salsa.Otherwise, must use pressure canner (240°F

+)

Temperatures for Food Temperatures for Food Preservation: Applying Preservation: Applying HeatHeat240 to 250°F Canning temperatures for low acid

vegetables, meat, and poultry in a pressure canner.

212°F Temperature water boils at sea level. Canning temperature for acid fruits, tomatoes, pickles, and jellied products in a boiling-water canner.

180 to 250°F Canning temperatures are used to destroy most bacteria, yeasts, and molds in acid foods. Time required to kill these decreases as temperatures increase.

140 to 165°F Warming temperatures prevent growth, but may allow survival of some microorganisms.

The Danger ZoneThe Danger Zone

40 to 140°F DANGER ZONE. Temperatures between 40°F - 140°F allow rapid growth of bacteria, yeast, and molds.

Temperatures for Food Temperatures for Food Preservation: Keeping it Cool Preservation: Keeping it Cool & Freezing& Freezing95°F Maximum storage temperature for

canned foods. 50 to 70°F Best storage temperatures for

canned and dried foods. 32°F Temperature water freezes. 32 to 40°F Cold temperatures permit slow

growth of some bacteria, yeasts, and molds. -10 to 32°F Freezing temperatures stop

growth of microorganisms, but may allow some to survive.

0 to -10°F Best storage temperatures for frozen foods.

Follow Instructions!Follow Instructions!When canning it is critical to

FOLLOW INSTRUCTIONS andDO NOT ALTER RECIPES!!Use only recipes tested by USDA,

The National Extension Service, or Ball Blue Book for absolute safety.

Recipes from friends, neighbors, and the internet may be unsafe.

Do Not Use the Following Do Not Use the Following MethodsMethods

Oven canning: Does not ensure precise temperatures needed for safety.

Open kettle canning: The temperatures never reach the proper canning temps needed

Do not Hot Water Bath can low-acid foods.

Pressure Canners vs. Pressure Canners vs. Pressure CookersPressure CookersIf you buy a pressure canner,

that can also be used as a pressure cooker, that’s great! (Such as the Presto 16qt or 23qt)

YOU CANNOT USE A PRESSURE COOKER AS A PRESSURE CANNER.