Food Preservation: Overview of Methodologies

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

2. 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

3. 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

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

5. 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

6. Freezing & Refrigeration Freezing • 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

7. 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

8. 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)

9. 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

10. 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.