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Perspectives in Nutrition 5 th ed. Gordon M.Wardlaw, PhD, RD, LD, CNSD PowerPoint Presentation by Dana Wu Wassmer, MS, RD.

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Presentation on theme: "Perspectives in Nutrition 5 th ed. Gordon M.Wardlaw, PhD, RD, LD, CNSD PowerPoint Presentation by Dana Wu Wassmer, MS, RD."— Presentation transcript:


2 Perspectives in Nutrition 5 th ed. Gordon M.Wardlaw, PhD, RD, LD, CNSD PowerPoint Presentation by Dana Wu Wassmer, MS, RD

3 Chapter 19: Food Safety

4 Foodborne Illness Major cause of diarrhea No real long-term health threat to the average healthy person May be serious for very young, very old, people with long term illness Usually results from unsafe food handling in the HOME

5 Why Are So Many Food Making Us Sick? Preference for “rare” meats Use of immunity suppressant medications Increase in the number of elderly Increase shelf life of products which allows for bacterial growth Centralized food production Increase consumption of imported ready-to- eat foods

6 Preservation of Food Prevents the growth of bacteria Salt, sugar, smoke, fermentation, drying Limit water available for bacteria Pasteurization, sterilization, refrigeration, freezing, irradiation, canning, chemical preservation Aseptic processing

7 Food Irradiation, Is It Harmful? Does not make food radioactive Breaks down chemical bonds, cell walls, DNA Controls/limits growth Approved to be used on raw meats, dried seasonings Safe, according to FDA Radura symbol on irradiated foods

8 Why Are Microbes So Harmful? Able to produce specific toxin Can invade intestinal wall Can produce infection Can be intoxicating We are constantly at risk for foodborne illness

9 How to Avoid Microbes At the Store Buy frozen, perishable last Place meats in separate plastic bags Don’t buy dented cans Buy only pasteurized milk/cheese Buy only what you need Avoid buying slimy, brownish, dry produce

10 Avoid Microbes At Home Wash hands thoroughly Keep counters, cutting boards, equipment clean and sanitized Prepare raw meat separately Thaw foods in refrigerator or cold running water or microwave Avoid coughing and sneezing over food Clean/wash fruits/vegetables thoroughly

11 Storage of Meats Use refrigerated ground meat within 1-2 days Use frozen meat with in 3-4 months

12 When in doubt, throw it out

13 How to Avoid Microbes When Cooking Thoroughly cook meat, fish, poultry, egg Cook stuffing separately Eat food right away Store “left-over” within 2 hours Serve cooked meat on clean plates Avoid partial cooking food for picnics

14 What To Do With Leftovers Keep hot foods hot & cold foods cold (<40º F or >140º F) Reheat leftovers to 165º F Store peeled, cut up produce in the refrigerator Keep refrigerator < 40º F

15 Temperature Danger Zone (Fig. 19-2) Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

16 Cross-Contamination From one contaminated source to clean source Unclean hands to food Must practice sanitary food-handling practice Expect same practice when eating out

17 Campylobacter jejuni Very heat sensitive 90% of poultry tested positive Destroys the mucosal surfaces of small and large intestine Symptoms include intestinal pain, fever, muscle pain, headache, diarrhea Appears 2-10 days after ingestion Treatment: antibiotics

18 Salmonella Ingestion of live bacterial causes problem Can be eliminated by normal cooking Symptoms: nausea, fever, headache, abdominal cramps, vomiting Appears 5-72 hours after ingestion Sources include animals, feces, egg, alfalfa sprouts, reptiles Greatest risk for cross contamination Treatment: fluids, rest

19 Shigella Sonnei Spread via fecal-oral route Common in day-care centers Symptoms include abdominal cramps, diarrhea, fever, bloody stools Appears in 1-3 days CAREFUL HAND WASHING IS A MUST!

20 Escherichia Coli Found normally in the intestinal tract Children and elderly are most at risk Common in ground beef and roast beef Destroyed by irradiation of meat, pasteurization, and thoroughly cooking Symptoms include diarrhea, bloody diarrhea, kidney failure, abdominal cramp, hemolytic uremic syndrome Symptoms appear 2-4 days after ingestion

21 Clostridium Perfringens Found in soil, intestinal tract, sewage “Cafeteria germ” Thrives in absence free of air Maintain proper holding temperature to prevent growth Reheat thoroughly to 165º F Symptoms similar to Salmonella without vomiting Symptoms appears 8-24 hours after ingestion

22 Listeria Monocytogenes Resist heat, salt, and acid Major sources are animals and human feces Destroyed by pasteurization Symptoms include flu-like symptoms (fever, headache, vomiting) Symptoms appears 7-30 days after ingestion

23 Staphylococcus Aureus Toxin produces nausea, vomiting, diarrhea, headaches, abdominal cramps Appears 2-6 hours after ingestion Do not develop immunity to toxin Lives normally in nasal passages and open sores Thrives in ~100º F and can withstand prolong cooking Common in custard, ham, egg salad, cream filled pastries

24 Clostridium Botulinum Causes botulism Spores can survive if there is insufficient heating and grows in the absence of air Common in canned, low-acid foods Symptoms include depressed nerve function, vomiting, abdominal pain, double vision, dizziness, respiratory failure Symptoms appears 12-36 hours after ingestion Avoid dented, rusted, swollen cans

25 Yersinia Enterocolitica Sources include water, chocolate milk, reconstituted dry milk, wild animals, livestock, tofu Thrives in cold (refrigeration) temperature Destroyed by sufficient cooking Symptoms include diarrhea, fever, headache, abdominal pain Symptoms appear 24-36 hours after ingestion

26 Vibrio Vulnificus From consumption of raw seafood Cooking destroys this organism Symptoms include diarrhea, fever, weakness, blood infection

27 Vibrio Cholerae (cholera) From contaminated water and food Especially in areas with poor sanitation Careful hand washing after defecating limits transmission Symptoms include vomiting, watery diarrhea Symptoms appear 2-3 days after ingestion

28 Viruses: What Are They? Need a living host to grow Take over cells Cause host cells to reproduce viruses’ genetic material (make more viruses) Kill host cells and spread more viruses Enter host via feces contaminated foods or undercooked shellfish Usually are heat, cold, and dry resistant

29 Viruses Destroyed by intense heat or irradiation Symptoms varies with virus Proper hand washing is a must Chlorinating drinking water also helps

30 Parasites: What Are They? Larvae in meat that can enter the body through the intestinal tract Can develop into adult nematodes (worms) Will reside in the host and consume nutrients

31 Parasites: Trichinella spiralis (trichinosis) From undercooked pork, meat Meat contains larvae Larvae resides in hosts’ muscle fibers Symptoms are flu-like Destroyed by thorough cooking

32 Parasites: Anisakis From raw fish Penetrates stomach lining May cause violent stomach pains 12 hours after ingestion Requires surgical removal of larvae Destroyed by thorough cooking or freezing for more than 72 hours

33 Parasites: Cyclospora cayetanensis Infects the small intestine Identified in Guatemalan raspberries Symptoms include diarrhea, vomiting, fatigue, muscle ache

34 Parasites: Cryptosporidium From birds, animals, and feces Found in public swimming pools & raw apple cider Symptoms include severe diarrhea, dehydration, nausea, fever, abdominal cramp

35 Why some fish may not be the smartest choice Scombroidosis from spoiled fish Dinoflagellates from microscopic algae Ciguatera from certain fish

36 Fungi Mycotoxins, a toxin produced from molds Lives on decaying or dead matters Digests food outside their cell walls Requires moisture to grow Growth halted by cooking and freezing Avoid consumption of moldy food

37 Aflatoxins May cause liver cancer Common in tree nuts (walnuts, pecans), peanuts, corn, wheat, oil seeds Cooking and freezing halt fungal growth but does not eliminate the myocotoxins already produced

38 Additives Added to limit spoilage Prevent undesirable changes Increase safety of foods Intentional food additives –Added directly to food Incidental food additives –Indirectly added as a contaminant (e.g., pesticide residue) –Regulated by the FDA since it is hard to ban

39 The GRAS (Generally Recognized As Safe) List Manufacturers do not have to prove safety Already regarded as safe Synthetic chemical is the same as natural

40 Safety of Additives Tested on 2 types of animals Determine the highest dose that produces no observable effects level (NOEL) Prorate the dose to human dose Divide the dose by 100 to establish a margin of safety If it is shown to cause cancer even at the high dose, it is taken off the market

41 Approval For A New Food Additive by the FDA Must identify new additive Give its chemical composition State how it is manufactured Specify method of measurement Proof of intended purpose Proof of safety Not to be used to deceive

42 Common Food Additives Acid or Alkaline agents Alternative Sweeteners Anticaking agents Antimicrobial agents Antioxidants Colors Emulsifier Curing and pickling agents

43 Nitrate a Curing and Pickling Agent Used to prevent the growth of Clostridium botulinum Converts to cancer causing nitrosamine in the stomach Vitamin C added can reduce the formation of nitrosamine Actual risk is low for normal people

44 Other Food Additives Fat replacements Humectants Leavening agents Maturing and bleaching agents Nutrient supplements Stabilizers and thickeners Sequestrants Flavors and flavoring agents Flavor enhancers

45 MSG Often used in Chinese foods Small percentage of people are sensitive (Chinese Restaurant Syndrome) Experience dizziness, sweating, rapid heart rate, nausea, vomiting, high blood pressure and headaches Symptoms appear 10-20 minutes after ingestion Found naturally in other foods (tomato, mushroom, parmesan cheese)

46 Natural Toxins Occurs naturally in foods Solanine from potato shoots Mushroom toxins Thiaminase in raw clams and mussels Protease inhibitor in raw soy beans Saponins in alfalfa sprouts

47 Lead Poisoning A heavy toxic metal Causes anemia, kidney disease, damage the nervous system Lead from solder joints, lead paint, playground, metal containers A high fat, low calcium, low iron diet absorbs more lead Thus, a low fat, adequate calcium and iron diet is recommended

48 Dioxin Cancer causing From trash burning From bottom feeding Great Lakes fish Exposure seen in people who consume locally caught fish

49 Mercury From large predator fish (shark, sword fish) Accumulates mercury in the fish These fish are tested more frequently for mercury level Not recommended for women of childbearing years Birth defects are common

50 Urethane From fermentation of alcohol Increase upon heating (of the alcohol) Causes cancer in animal studies

51 Polychlorinated Biphenyls (PCBs) Used in industrial products Linked to liver tumors and reproductive problems in animals Still found in freshwater fish Limit established for uses by FDA

52 How to Reduce Your Exposure to Toxins Know what foods pose a risk Practice moderation and variety Trim fat from meat and fish Wash fruits, vegetable thoroughly Cook meat thoroughly

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