1. Types of Food Preservatives Maintaining freshness

2. Preservatives – substances add to food to prevent or slow spoilage and maintain natural colors and flavors 2 reasons for food spoilage – Microbial contamination – Fats reacting with oxygen (Oxidation) Preservative criteria: – Nontoxic – Functional – Flavorless – economical

3. Antimicrobial agents – prevent the growth of microbes in food Salts and sugars – Oldest and most used types – Dehydrate food (microbes can’t grow without water Nitrates (NO3) – NaNO3 most common – Controls the bacteria that cause botulism – React with amino acids to form nitrosamines (carcinogen) Illegal according to Delaney act but risk of botulism to high Legislation allows use until safe alternative found

4. Antimicrobial agents cont. Acids – Acetic, ascorbic, citric, lactic, benzoic, and propionic – Prevent microbe growth by lowering pH of food – Calcium propionate (C 6 H12CaO 5 ) prevents mold in bread – Sorbic (C 6 H 8 O2)and benzoic acid (C 6 H 6 O2) work together Control mold, yeast, and bacteria in soft drinks

5. Antioxidants Protect foods from changes caused by exposure to oxygen Interfere with the formation of free radicals – Atoms or groups of atoms with 1 or more unpaired electrons They are unstable and highly reactive Cause fats to become rancid ad trigger enzymatic browning Can cause the formation of carcinogens Antioxidants donate hydrogen atoms to free radicals – Create a stable compound see pages 467-468 for more info on Antioxidants

6. Sulfites Controversial group of antioxidants Salts that contain sulfur – Sulfur dioxide, sodium sulfite, sodium and potassium bisulfite Added to frozen and dried produce to prevent browning Use on fresh produce banned by FDA 1986 – Dangerous allergic reactions Can’t be used on foods that are a source of thiamin – Sulfites destroy thiamin