Food Preservation An Overview of Methodologies

Food Preservation Food preservation is the name for a number of processes that help to preserve food. For thousands of years, humans have used methods of preserving food, so that they can store food to eat later. The simplest methods of preserving food, such as drying strips of fish or meat in the hot sun have been used for thousands of years, and they are still used. Food preservation usually involves preventing the growth of bacteria, fungi (such as yeasts), or any other microorganisms. Maintaining or creating nutritional value, quality and flavor is an important aspect of food preservation.

Food Preservation Pickling Common ways of preserving food are: 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. Pickling Preserve foods in vinegar or other organic acid Lower pH inhibit bacteria and microorganisms. 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 3

Helpful microorganisms lower pH Can make food more nutritious Conti… Fermenting Helpful microorganisms lower pH Can make food more nutritious Examples: Yogurt Wine Most Cheeses Sugar reduces the water content Lower pH Cooked during the process All of the above inhibit microorganism growth 4

Curing: Salt reduces water content The addition of Nitrites (NO2) and Nitrates (NO3) inhibit the bacteria Clostridium botulinum, which causes botulism Smoked foods are also cured. 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 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

Foods with pH below 4.6, high acid foods 212 degrees Fahrenheit 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 (produces toxin) which cause of Botulism (weakness, fatal illness). 7

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.

Definition of Food Additives A chemical added to a particular food to preserve flavor, or enhance its taste and appearance during processing or storage which could affect the characteristics of the food, or become part of the food.

Introduction of Food Additives The term food additive means any substance the intended use of which results, or may reasonably be expected to result, directly or indirectly in its becoming a component or otherwise affecting the characteristics of any food (including any substance intended for use in producing, manufacturing, packing, processing, preparing , treating, packaging, transporting, or holding food.

Introduction Food additives can be divided into two major groups Intentional additives Chemical substances that are added to food for specific purpose Are regulated by strict governmental controls Incidental additives We have little control over incidental or unintentional additives

Additives uses Raise the nutrient value of food. Prevent the formation of lump (caking) by anti caking agents (sodium aluminosillicate is used in dry milk and salts). Bleaching agents, dough conditioners, colouring agents,emulsifiers & stabilizers as preservatives & prevent fats from rancidity to slow growth of microorganisms.

Common Food Additives Ascorbic Acid (Vitamin C): It is used in cereals, cured meats & fruit drinks as an antioxidant, colour stabilizer or as a nutrient Artificial & natural flavouring: They are used in cereals, candy, desserts, soft drinks &many other foods as “mimic” of natural flavours Ascorbic Acid (Vitamin C)

Food Additives Butylated Hydroxytoluene (BHT) It is used cereal, chewing gum, & potato chips as an antioxidant. It keeps oils from going rancid. Gums: (Arabic, guar, locust bean) It is used in beverages, candy, cottage cheese, dough, drink mixes, frozen pudding, ice cream, salad dressings as stabilizers & thickening agents . Butylated Hydroxytoluene (BHT) . Butylhydroxytoluene

Food Additives Sodium Benzoate: It is used in fruit juice, pickles, preserves soft drinks to prevent growth of micro organisms in acidic foods. Sodium Benzoate

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