Food Preservation for Food Processors Part I An interactive module about acidic foods Module...
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Transcript of Food Preservation for Food Processors Part I An interactive module about acidic foods Module...
Food Preservation for Food Processors Part I
An interactive module about acidic foods
Module designed by Julie Garden-Robinson, Ph.D., L.R.D., Food and Nutrition Specialist, 2014
The following tips will help you navigate through each module. Click to go back and to move forward
in the module. Before you begin, you’ll take a pretest.
The pretest will open in a new window. When you are finished with the pretest, close
the window to return to the module. A symbolizes a question slide. You’ll
need to click forward to see the answer.
Click this button to return to your position in the module after reading the definition slide.
When you are finished with the module, you will take a post-test. The post-test will open in a new window. When you are finished with the post-test, close
the window to return to the module.
PretestBefore we begin, let’s take a
pretest to see how much you already know. Click here for the pretest.
Have a bright idea?Everyone loves my salsa and alwaysasks me to bring it to potlucks.Maybe I should start selling it. I bet Icould make a fortune. Maybe I canretire and buy a house in Arizona –no, Florida. Heck, maybe both!
Oh, no! There are regulations?
Hey, wait. Don’t give up. Go through this interactive module.It tells you what you need to knowabout processing acidified foods.Salsa is an acidified food.
Before we discuss the acidification process and regulations, let’s go over some basics about types of preservation and also what preserving means.
Food PreservationDefinition: The process of treating and handling food insuch a way that it stop or greatly slows spoilage to prevent foodborne illness while maintaining nutritional value, density, texture and flavor.
Factors that affect food spoilage Water availability (moisture) Oxygen pH Temperature
True or false: Oxygen is a factor affecting food spoilage.a. Trueb. False
Click the forward button to see the answer.
True or false: Oxygen is a factor affecting food spoilage.
a. Trueb. False
Oxygen is a factor affecting food spoilage.
Water Availability “Water availability” refers to the amount
of water available for microbial growth. It is shown on a scale from 0 to 1.
Bacteria grow in moist environments, so the higher the water availability, the greater the risk for microbial growth.
A solute such as salt or sugar added to water “soaks” up the water, making it unavailable for bacterial growth.
Water Availability Scale
0aW
Bone dry Pure
water
0.2aW
Very dry (instant coffee, milk powder, etc.)
0.99aW
Moist fresh food (meat/fish)
0.6aW
Dried fruit
0.8aW 1aW
Water Availability Bacteria, mold and yeast need a certain
amount of water available to grow. As the water availability decreases, bacteria, mold and then yeast cease to grow. Bacteria stop growing below 0.85aW Molds stop growing below 0.75aW Yeast stops growing below 0.6aW
Water availability of some common foods
Food Example Water Availability
Cheese spread 0.95
Soy sauce 0.80
Fudge sauce 0.83
Soft, moist pet food 0.83
Peanut butter 0.70
Dry milk 0.70
Liverwurst 0.96
Salami 0.82
*Water availabilities greater than 0.85 support bacterial growth.
True or false: High water availability supports bacterial growth.
a. Trueb. False
Click forward to see the answer.
True or false: High water availability supports bacterial growth.
a. Trueb. False
Most bacteria grow best in products with high water availabilities.
Oxygen Aerobic reactions need oxygen.
The browning of fruit is one example.
Anaerobic reactions do not require oxygen. Clostridium botulinum is a type of bacteria that
does not need oxygen to survive.
Fill in the blank: Bacteria that need oxygen to survive are ______.a. Aerobicb. Anaerobic
Click forward to see the answer.
Fill in the blank: Bacteria that need oxygen to survive are ______.a. Aerobicb. Anaerobic
Aerobic bacteria need oxygen to survive and grow.
pH Foods have different pH values. Chemical reactions are decreased at very
high and very low pH. A pH meter is used to determine the pH
level of foods.
Temperature Warm temperatures increase chemical
reactions. High temperatures can kill harmful
microorganisms. High temperatures are critical for certain
preservation methods: Pressure canning Boiling-water canning
Low temperatures can slow and eventually stop chemical reactions.
Preserve foods by: Adding an acid Adding salt Drying to remove moisture Adding sugar Adding chemical preservatives Heating
=Vinegar (Acid)+
Now that we know what to control to prevent food from spoiling, let’s reviewsome methods of preservation.
Types of preservation:DryingCuring and smokingFreezing and refrigerationFermentationPressure canningMaking jam and jellyPickling/acidification
Which of the following is a preservation method?a. Dryingb. Freezingc. Smokingd. All of the above
Click the forward button to see the answer.
Which of the following is a preservation method?a. Dryingb. Freezingc. Smokingd. All of the above
“D” is the correct answer.
Drying One of the oldest methods of preservation Removes moisture to delay and prevent
bacterial growth Safe and easy-to-learn method of
preservation A food dehydrator
often is used Meats and fruits, such
as jerky, apples, bananas, mangos and tomatoes, arepopular items to dry
Fill in the blank: Drying preserves food by ______.a. adding an acidb. lowering the temperaturec. reducing the moisture content
Click the forward button to see the answer.
Fill in the blank: Drying preserves food by ______.a. adding an acidb. lowering the temperaturec. reducing the moisture content
“C” is the correct answer. A food dehydrator or oven on a low temperature is used to dry foods for preservation.
Curing and Smoking Meats must be cured before they are
smoked. Curing uses salt to reduce the moisture
available to microorganisms. Nitrates and nitrites are added to inhibit
the growth of Clostridium botulinum. Curing can take several hours to several
weeks.
Fill in the blank: Curing preserves food by ______.a. adding an acidb. lowering the temperaturec. reducing the moisture content
Click the forward button to see the answer.
Fill in the blank: Curing preserves food by ______.a. adding an acidb. lowering the temperaturec. reducing the moisture content
"C” is the correct answer. Salt is added to products being cured to reduce the moisture content.
Smoking After a product is cured, it can be smoked. Smoking usually is done in a smokehouse. The combination of heat and smoke dries
and preserves the food. Smoking adds flavor to the product. Meat, poultry, game and fish all can be
smoked.
Freezing and Refrigeration Are commonly used processes for
preserving Stops the growth of bacteria (freezing) or
slows the growth of bacteria (refrigeration) Slows most chemical reactions
Does freezing food kill bacteria?a. Yesb. No
Click the forward button to see the answer.
Does freezing food kill bacteria?a. Yesb. No
“B” is the correct answer. Bacteria is not killed by freezing foods, but the lower temperature slows the growth of bacteria.
Fermentation A microorganism such as yeast is added to
a product to convert carbohydrates into an acid or an alcohol. These microorganisms consume the food and
produce byproducts. Yogurt is one example.
Bacteria is added to milk. The bacteria eat the sugar and produce lactic acid.
Lactic acid reduces the pH of yogurt, which inhibits bacteria growth.
Which preservation method involves bacteria or yeast?a. Dryingb. Fermentingc. Picklingd. Freezing
Click the forward button to see the correct answer.
Which preservation method involves bacteria or yeast?a. Dryingb. Fermentingc. Picklingd. Freezing
“B” is the correct answer. Yogurt is an example of fermentation.
Pressure Canning Kills bacteria with high temperatures.
A temperature greater than 240 F must be reached.
Pressure canning is used when the product has a pH above 4.6.
Jams and Jellies Sugar reduces the amount of available
water. Jams and jellies normally have a pH lower
than 4.6. Jams and jellies cook during processing.
Post-test Now you have some basic knowledge
about why we preserve food and the methods of food preservation.
Before you move on to the next module, let’s take a post-test to see what you’ve already learned.
Click here to take the post-test
Learn more about food preservation with the following online resources National Center for Home Food Preservation
www.uga.edu/nchfp/ FDA - Acidified and Low Acid Canned Foods
www.fda.gov/food/guidanceregulation/guidancedocumentsregulatoryinformation/acidifiedlacf/default.htm
NDSU Extension Service Food Preservation and Storage www.ag.ndsu.edu/food