Food Preservation: Overview of Methodologies By Lauren Woodliff for the CTAE Resource Network

Drying Oldest known method; 12,000 B.C. Sun, Wind & Fire Fire also used to dry fruits, vegetables & herbs Modern day examples of dried preserved food: Beef Jerky Sun Dried Tomatoes Sun and wind were found to naturally dry and preserve foods Oldest known method; 12,000 B.C. Fire also used to dry fruits, vegetables & herbs Wild game, fish and early domesticated animal meat were also dried Modern day examples of dried preserved food: Beef Jerky Sun Dried Tomatoes

Pickling & Fermenting Pickling Preserve foods in vinegar or other organic acid Lower pH inhibit bacteria and microorganisms Fermenting Helpful microorganisms lower pH Can make food more nutritious Examples: Sauerkraut Yogurt Wine Most Cheeses

Sugar reduces the water content Lower pH Cooked during the process Jam & Jelly Sugar reduces the water content Lower pH Cooked during the process All of the above inhibit microorganism growth

Curing Curing: Salt reduces water content The addition of Nitrites and Nitrates inhibit the bacteria Clostridium botulinum, which causes botulism Smoked foods are also cured

Freezing & Refrigeration Zero degrees Fahrenheit Easiest, least time-consuming and most convenient method Refrigeration 40 degrees Fahrenheit or below Prolongs shelf life of food Slows growth of most microorganisms but does not kill or inhibit growth Food will eventually spoil

Canning Extreme heating Oxygen is driven out Creates a vacuum seal Two methods: Water Boiling Canning Pressure Canning The method that should be used depends on the type of food and its pH

Boiling Water Canning Foods with pH below 4.6, high acid foods 212 degrees Fahrenheit Kills most food spoiling/illness causing bacteria and microorganisms except Clostridium botulinum (cause of Botulism)

Pressure Canning Foods with ph above 4.6, low acid foods 240 degrees Fahrenheit Only pressure canning can reach temperatures this high Kills the bacteria, Clostridium botulinum

Summarize and Discuss Why is it important to preserve food for later use, especially before modern day packaging and refrigeration? Why is important to choose the right method for different foods? What are some of the factors that determine what method to use? Think about the food that you eat on a daily basis that have been preserved using the methods that have been discussed.