Lecture 6
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What is ionizing Radiation?
Radiant energy with some penetrating power which do not produce radioactivity in treated foods -Need penetrating power for food irradiation
What is cold pasteurization?
Radiation of food does not produce significant heat in foods
What is the relationship between wave frequency, penetrating power and wavelength?
Higher frequency, higher penetrating power and lower the wavelength
What can UV lights do to food?
Inactivate microorganisms on the surface of foods (meats) Wave lengths from:13.6-400
Are x rays used to irradiate food?
No, currently at the experimental
Do alpha beta and delta wavelengths help with irradiation?
α Particles: Helium (He) atom minus 2 Electrons (Low Penetration) β Particles: High Energy Electrons δ Rays: Strong Penetration Power
In 1985 what did the FDA allow for irradiation?
Strawberries Poultry Ground Beef Pork
Is irradiation a type of food preservation?
Yes because in the process you are destrouing the spoilage and mircooragnisms and therefor extrending the shelflife of the food Onion and potato for sprout preveention Consumer demand isnt high in canada so its not sold, people sitill concerned about safety
What are the 3 main thing irradiation is used for?
Control Insects in Foods and Spices Inhibit Sprouting Destroy Vegetative Cells of Microorganisms -Actively reeproducing cells without spores
What are the sources of ionizing radiation?
Natural Radioactivity • Uranium • -Breakdown of atomic structure produce radiation energy Synthetic Radioactivity • Cobalt – 60 • High energy bombardment of atoms Flow of Electrons
What is a RAD?
Radient absorbed dose -Is measure of ionizing energy absorbed
What RAD do we use for food?
Low = up to 1 KGY, Med 1-10 KGY, High = 10-50 KGY Use low-med in food kilogray High may get negative aspects of the process of irradiatioini
What are the different measures of RADs?
GRAY = 100 RADS KRAD = 1000 RADS MRAD = 1 000 000 RADS
What must foods that have used irradiation put on their labels?
Must carry the International Food Irradiation Symbol (RADURA) Include a Written Statement: • Treated with Irradiation • Treaded by Irradiation • Irradiated
What are the factors important in food radiation?
1) Safety and Wholesomeness of the Treated Food - Final orduct is safe for human consumption 2) Resistance of Food to Organoleptic Quality Damage - ensory properties of the foods, depeends on chemical copm and structure of foods 3) Resistance of Microorganisms - C bot is the most reesisitant sporre former 4) Resistance of Enzymes - 20mrad to destroy because are very resistant 5) Cost Higher irradiaiton =higher costs
The commercial use of irradiation depends on what?
Demand for Benefits Provided Competitiveness with Alternative Processes Willingness of Consumers to Buy
What are the applications of irradiation?
Increase shelf life Pathogenic reduction Disinfestation
How does irradiation increase shelf life?
↓ # of Spoilage M.O. (~ 1-10 KGY) i.e. Meat, Vegetables, Fruits Inhibit Sprouting i.e. Potatoes, Onions ↓ Rate of Ripening (~ 1 KGY) i.e. Strawberries: Shelf-life↑ (5 days to 15 days
How does irradiation lead to pathogenic reduction?
Enables the microorganisms that causes disease/sickness Salmonella (poultry), Campylobacter … Trichinella spiralis parasites (Trichinosis in pork)
How does irradiation lead to disinfestation?
Disinfestation (insects) As an alternative to chemical fumigation Grains, spices, fruits, vegetables
What is the safety of irradiated foods on nutrients, toxins, carcinogenic substances and radioactivity ?
nutrients: Use low-med irradiation the nutrients arent affected signifiacntly toxins: No toxinc produced carcinogenic substances : No produced radioactivity: Food doesn’t become radioactive
What are the disadvantages of radiation?
Off-flavour and off-odour Destruction of B vitamins Degradation of protein and other nitrogen compounds Production of ammonia, hydrogen gas, CO2, H2S Rancidity of fats Tissue softness of vegetables