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PUBH 1517 - (Chapter 14) Food Safety & Food Technology 1

PUBH 1517 - (Chapter 14) Food Safety & Food...

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Unformatted text preview: Nutrition: Concepts and Nutrition: Concepts and Controversies, 8 ed Chapter 14 Food Safety and Food Technology FDA: Food & Drug Administration FDA: Food & Drug Administration The major agency charged with monitoring the food supply in the U.S. Is the agency that decides what additives may be used in foods, based on safety and effectiveness Has identified a list of 5 areas of concern, in order of priority FDA Prioritized Concerns FDA Prioritized Concerns Microbial food­borne illness Natural toxins in foods Residues in foods 1. 2. 3. 1. 2. Environmental contaminants other than pesticides Pesticides Animal drugs Nutrients in foods Intentional food additives Food­borne Illness Food­borne Illness Episodes of food poisoning far outnumber any other kind of food contamination In U.S., estimated 81 million people become ill & about 9,000 die each year from food­borne illness Can be caused by actual infection with bacteria (as with salmonella & E. coli) or by toxin produced by bacteria (as with botulism and staph) Majority of cases result from errors made in food handling AFTER purchase, but incidents which result from pre­purchase contamination affect larger numbers of people at once & get much more media attention Botulism Botulism Caused by the toxin of Clostridium botulinum (anaerobic) which grows in improperly canned (esp. home­canned) foods Improperly prepared or stored vacuum­packed foods Oils flavored with herbs, garlic, vegetables, etc. which are stored at room temperature Grows in low acid conditions Often fatal, & leaves prolonged symptoms See p. 509 & 511 for warning signs, onset time, how to avoid Toxin can be destroyed by heat (boiling for 10 minutes) Food Safety: When making flavored oils, wash and dry the herbs before adding them to the oil, and keep the oil refrigerated. Top Four Causes Top Four Causes of Foodborne Illness Campylobacter: Undercooked poultry, unpasteurized milk Salmonella: uncooked or undercooked eggs, unpasteurized milk, raw meat & poultry, vegetables & fruits E. coli: Raw or undercooked beef, unpasteurized milk, raw vegetables & fruits, contaminated water Norwalk­like viruses: Undercooked seafood (contaminated by human feces from boat bilge) Incidence of Top Two Incidence of Top Two Campylobacter: greatest number ­ est. 2,453,926 cases/year in U.S. (Almost double that of estimated Salmonella cases. Found on up to 80% of chickens, 20% representing a strain resistant to antibiotics. Onset 2­5 days after eating. Salmonella: estimated 1% of U.S. population experiences infection yearly. Food Safety Temperatures (Fahrenheit) and Household Thermometers. Thermometers. Meats & Poultry Meats & Poultry Especially prone to bacterial growth due to high protein & moisture content, as well as probable contamination with bacteria Should thaw meats in refrigerator Must avoid cross­contamination of other foods Never place where juices can drip on other foods Wash hands and thoroughly clean surfaces used for preparation of meats Never place cooked meat back on plate used for raw meat Must cook to proper temperature to kill microbes Meats, Poultry (cont.) & Eggs Meats, Poultry (cont.) & Eggs Best NOT to cook large, thick, dense foods such as roast or meatloaf in the microwave due to probability of uneven heating resulting in cool spots. Due to increased likelihood of Salmonella contamination, eggs should be cooked until whites are set firmly & yolks begin to thicken. If recipe calls for raw egg (which will not subsequently be cooked), best to use pasteurized egg product Elderly, infants, very young children, & anyone with compromised immune system should not even consume pasteurized egg Neurotoxins in Seafoods Neurotoxins in Seafoods Ciquatera: ciquatoxin present in microorganisms in reefs, called dinoflagellates. Most commonly associated with grouper, red snapper, & barracuda, primarily from the Caribbean & South Pacific Islands Causes nausea, vomiting, abdominal cramps, watery diarrhea, then numbness, shooting pains in legs. Toxin not destroyed by cooking, freezing, digestive enzymes. Seafood Neurotoxins, cont. Seafood Neurotoxins, cont. Red Tide: may occur between June & Oct on Pacific & New England coasts due to microorganisms In shellfish. Causes burning or prickling sensation in mouth after 5 to 30 minutes, followed by nausea, vomiting, muscle weakness, & loss of feeling in hands & feet. Recovery usually complete. Parasites Parasites Tapeworms, flatworms, roundworms may enter food & water through fecal material & soil Usually killed by freezing & always by high temperature One type of roundworm, found in raw fish, actually bores a hole in a person’s stomach within an hour of consuming it. Frequent incidence in Japan. Study in Seattle found that about 40% of raw fish samples (from fish used in sushi) contained roundworms, but the worms were dead due to the fish having been frozen. Mad Cow Disease Mad Cow Disease Bovine spongiform encephalopathy Suspected of causing at least 90 human deaths in England & France Appears to have started when cows were given sheep intestines & parts of the spinal cord in their feed Some of the sheep harbored a type of protein called a prion, that can transmit disease when consumed by a similar species Food Preservation Methods Food Preservation Methods Main objective is to extend usable life of a food There are sometimes trade­offs in regard to nutrient content Canning Kills all microorganisms using high­temperature­short­time (HTST) principle Seals out air Some destruction of water­soluble vitamins by the heat, but much of loss due to diffusion into canning liquid Minerals can also diffuse into the liquid Fat­soluble vitamins not destroyed (heat stable) & do not diffuse into the liquid Food Preservation (cont.) Food Preservation (cont.) Freezing Nutrient content of frozen foods similar to that of fresh foods, & can be even higher due to fresh foods being picked before ripeness and spending a lot of time in transport & in refrigerator Vitamin C losses occur when tissues are broken & exposed to air (as in chopped broccoli) Maximum nutrient preservation requires temperature of zero degrees Fahrenheit or lower Food Preservation, cont. Food Preservation, cont. Drying Vacuum puff drying and freeze drying preserve nutrients much better than methods which use heat Sulfite additives used for some foods to prevent browning Modified Atmosphere Packaging Either removes air (vacuum) or replaces air with oxygen­free gas Used for bagged chopped salads, fresh pasta, meats, prepared foods, coffee, etc. Requires refrigeration to keep the food safe Increases shelf life & preserves nutrients partly by slowing down enzyme­induced breakdown Steam vegetables or cook them in a microwave oven. microwave ...
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