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How LONG Does Food Last?

How LONG Does Food Last?. Michelle Lloyd Department of Nutrition, Dietetics and Food Science Brigham Young University 15 June 2009. General Principles. Sensory. Nutritional. Toxicological. What defines shelf-life?. Is it edible? appearance flavor texture. Is it nutritious?.

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How LONG Does Food Last?

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  1. How LONG Does Food Last? Michelle Lloyd Department of Nutrition, Dietetics and Food Science Brigham Young University 15 June 2009

  2. General Principles

  3. Sensory Nutritional Toxicological What defines shelf-life? • Is it edible? • appearance • flavor • texture Is it nutritious? Is it safe?

  4. Vitamin Loss SOURCE: Institute of Food Technologists

  5. Vitamin Stability Caution: These conclusions are oversimplifications and may not accurately represent stability under all circumstances. Source: Fennema’s Food Chemistry, 4th Edition, p 442; Adapted from Harris, RS (1971). General discussion on the stability of nutrients, in Nutritional Evaluation of Food Processing

  6. What affects shelf-life of food? • Composition • Water • Fat • Protein • Carbohydrate • Other components • Storage Conditions

  7. Humidity Air Light Temperature To preserve your food storage, keep it away from… SOURCE: Oscar A. Pike, “Storing Fats and Oils,” Ensign, June 1999, 71

  8. Stored ~26 yrs Fresh Effect of Humidity Nutrient Loss • Thiamin -71% • Riboflavin -21% • Vitamin A -70% • Lysine -80% ~3% moisture >5% moisture From BYU Master’s Research of Michelle Lloyd, 2003

  9. Effect of Air (Oxygen) Oxygen absorber packets can extend shelf-life Oxygen reacts with food • Vitamin loss • Off-colors • Off-flavors • Allows bugs to survive

  10. Effect of Light • Speeds up reactions • Vitamin loss • Off-colors • Off-flavors

  11. Effect of Light on Hexanal in Whole Milk Powder

  12. Effects of Temperature Figure 173 – Dehydrated nitrogen-packed tomato samples after 30 months storage at 40°F, 70°F, and 100°F. From BYU Master’s Thesis of Amy Norseth, 1986

  13. Effects of Temperature Hot storage Ideal storage Bread made from ~20 year old wheat

  14. Wet-Canned Foods Source: “Progress in the Tin Plate Industry,” Food Technology, Vol. 5, #10, 1951 and Food Company Information

  15. Corroded Cans

  16. BYU Research on Long-term Storage

  17. Collecting Samples LDS Church News, 29 Dec 2001, 10

  18. Collecting Samples

  19. Foods Tested at BYU (from residential locations) • Nonfat Dry Milk • Oatmeal • Instant Potatoes • Rice • Dried Apples • All-Purpose Flour • Baking Powder • Powdered Eggs • Macaroni • Pinto Beans • Wheat • Cornmeal • Margarine Powder • Split Peas • Dehydrated Carrots

  20. Dehydrated apple slices stored up to 30 yrs Dehydrated potatoes stored up to 30 yrs Is it Edible? From BYU Food Storage Research, 2003

  21. Mark whether or not you would drink each sample in an emergency situation Is it Edible? SOURCE: Lloyd MA, Zou J, Ogden LV, Pike OA. 2004. Sensory and Nutritional Quality of Nonfat Dry Milk in Long-term Residential Storage. J Food Sci 69(8):S326-31.

  22. Is it Nutritious? • In general, the vitamins we have measured in properly stored foods are fairly stable over time. • Thiamin • Riboflavin • Vitamin C • Vitamin E SOURCE: Lloyd MA, Zou J, Ogden LV, Pike OA. 2004. Sensory and Nutritional Quality of Nonfat Dry Milk in Long-term Residential Storage. J Food Sci 69(8):S326-31.

  23. Is it Nutritious? Vitamin C stores well in dry form From BYU Food Storage Research, 2004

  24. Is it Safe? • Ames test for mutagenicity • Tested rice stored long term Conclusions “The results of this study suggest that rice held in accelerated and long-term storage does not increase in mutagenic compounds.” Pahulu HF et al. 2007. Change in mutagenicity in white rice after accelerated and long-term storage . J Food Sci. 72 (2): C126-C131

  25. "Life Sustaining" Shelf-Life http://providentliving.org/content/display/0,11666,7798-1-4224-1,00.html

  26. Shelf-life summary Weeks: Fresh produce 1-2 years: Cooking Oil, Flour Several years: Wet Canned Foods, Yeast 15-30 years: Powdered Milk, Oats, Instant Potatoes, Dried Apples, Macaroni Pasta, Pinto Beans 30+ years: Wheat, White Rice No known limit: Granulated Sugar, Salt, Baking Soda, Baking Powder

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