Food Borne Illness Food Borne Illness n Food
Food Borne Illness
Food Borne Illness n Food Borne Illness Can be caused by: 1. 2. 3. Food Borne chemicals( non living Toxins ) Food Borne Infections ( Living organisms ) Food Borne Physical objects
Food Borne Toxins 1. Food Poisoning Food Borne Toxins ( non living chemicals ) 1. Generated by Microbes • Bacteria • Fungi • Algae 2. Man made toxins • Agricultural residues • Antibiotics • Preservatives 3. Naturally occurring toxins • Fish • Plants
Microbial Food Poisoning Toxin in food 1. Toxins that are destroyed by heating n n 2. Clostridium botulinum Clostridium perfringens Toxins that are Not destroyed by heating A. Produced by bacteria Staphylococcus aureus Bacillus cereus B. Produced by Algae C. Produced by Fungi : mycotoxins D. Natural toxins
2. Food Borne Infections 1. Causes by Bacteria that must grow in food before eaten • Require large infective dosage n Only Bacteria 2. Caused by Organism that do not have to grow in the food before it is eaten • Require small infective dosage Bacteria n Viruses n Parasites n
Microbial Infections n Causes by Bacteria that must grow in food before eaten • Require large infective dosage n Only Bacteria
Infections that require large infective dosage Campylobacter jejuni Salmonella spp. Clostridium perfringens is both food poisoning and infection Vibrio parahaemolyticus and other vibrios Escherichia coli - Enterotoxigenic (ETEC) Enterohemorrhagic HUS Listeria Yersinia enterocolitica both grow in refrigerator
Also cause gangrene
n Clostridial. Food borne infections 1. Gastroenterritis - Cl perfringens Type A 2. Pig-bel Cl. perfringens type C n 3. Acute colitis - Cl. difficile / gut organism • Commonest cause of ‘nosocomial’ diarrhoea
Clostridial food infections n C. perfringens • Not all are food poisoning strains n Normal inhabitant of gut • Survival of heat resistant spores in bulk meals • Sporulation in gut - Short IP and watery diarrhoea for 24 -48 hours n Pig Bell • - Beta toxin production by C. prerfringens type C – Necrotizing enteritis (Pig bell)
Perfringens Infections in USA 2000 n Principal symptoms Intense abdominal cramps, diarrhea n n Potential food contamination n Meat, meat products, gravies Toxin is heat lable but spores survive heat and germinate in intestine No. of illnesses n 248, 520 No. of deaths n 7
Listeria monocytogenes n The illness – invasive form, continued - infective dose – 100 to 1 000 cells - pregnant women, newborn babies, the elderly & AIDS patients - Most heat resistant non-sporing bacteria - Need 73 C for 48 sec so survives milk pasteurising (730 C / 15 sec)
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Salmonella n Salmonella • Classification has been changing in the last few years. • There is now 1 species: S. enteritica, and 7 subspecies: 1, 2 , 3 a , 3 b , 4 , 5, and 6. • Subgroup 1 causes most human infections • 2000 sub species
Enterobacter sakazakii n n n Enterobacter sakazakii a Gram-negative rod-shaped pathogenic bacterium. It is a rare cause of invasive infection with historically high case fatality rates (40– 80%) in infants. From contaminated infant formulas E. sakazakii as a now classified into a new genus, Cronobacter, comprising five species For survivors, severe lasting complications can result including neurological disorders.
Campylobacter n The illness - incubation – 2 to 5 days febrile prodrome watery/bloody diarrhoea, abdominal pain & nausea
Campylobacter Slender, curved shaped morphology Exponential growth
Campylobacter jejuni
Yersinia enterocolitica n Characteristics - grows at wide range of temperatures (0 to 44 0 C), aerobically & anaerobically - withstands freezing & survives in damp soil
Yersinia enterocolitica n Sources - human – person-to-person, hospitals animal – primary source is pigs (tongue & tonsils), companion animals, rats & insects - food – pork & pork products - environment – drinking & surface water, sewage sludge
Food Borne Infections n Organisms do not have to grow in the food before it is eaten: Bacteria Typhoid Cholera Mycobacterium Brucellosis Q-fever Anthrax Viruses Hepatitis A Polio Rotavirus Norovirus Parasites Protozoa Amoeboid disentry Toxoplasmosis Giardia lamblia Cryptosporidium Helminths Nematode Tapeworms
Viruses n n Hepatitis A and E Norovirus group
Hepatitis A n n n Source: Human intestine Illness: Infection Symptoms: Fever, malaise, nausea, abdominal discomfort, jaundice Foods: Cold cuts, sandwiches, fruit juices, milk and milk products, vegetables, salads, shellfish, iced drinks Transmission: Fecal contamination of food or water Control: Proper cooking, preventing crosscontamination, good sanitation, employee hygiene
Norovirus Group n n n Source: Human intestines Illness: Infection Symptoms: Self-limiting and mild; nausea, vomiting, diarrhea, abdominal cramps, fever Foods: Salad ingredients, raw or insufficiently cooked clams and oysters Transmission: Fecal contamination of food or water Control: Proper cooking, good sanitation, employee hygiene, preventing crosscontamination
Parasites n n n Round worms Tape worms Protozoa
Fish Nematode n n n n Parasite: Nematode (herring worm) Source: Raw or undercooked fish (salmon, tuna, herring, mackerel, squid, anchovies) Illness: Infection Symptoms: Tickling sensation in throat to acute abdominal pain and nausea Transmission: Consumption of raw or undercooked fish Control: Proper cooking of fish, commercial freezing of fish to be consumed raw Distribution: Worldwide, with higher incidence in areas where raw fish is eaten (e. g. , Japan, Pacific coast of South America, the Netherlands).
Trichinella spiralis n n n Parasite: Nematode Source: Pork and bear meat Illness: Infection (Trichinosis) Symptoms: Fever, muscle soreness, pain and swelling around the eyes. Chest pain may be experienced since the parasite may become imbedded in the diaphragm. Transmission: Raw or improperly cooked infected pork or bear meat Control: Thoroughly cook pork and other potentially infected meats, cook garbage fed to hogs, avoid crosscontamination of beef with pork
http: //a. abcnews. com/Health/Pain. Management/story? id=6309464&page=1 http: //www. youtube. com/watch? v=GMSc 2 RZ 19 Us
Hydatids n n n This tapeworm normally cycles between carnivores such as dogs, herbivores such as sheep as intermediate hosts. The adult tapeworms are small - rarely more than three segments long and cause minor symptoms in the dog. Upon eating the eggs from the dog faeces, the intermediate host develops the hydatid cyst. The cysts may grow to the size of football and generate many parasites Inside the cysts, form what is known as hydatid sand
n Food Poisoning
Staphylococcal Food Poisoning Characteristics: n Acute onset of cramps, vomiting, nausea, occasional diarrhea, low body temperature and blood pressure. n Recovery is usually complete within 24 hours. n Mortality is low in healthy individuals, higher among immunosuppressed individuals. n Pathogens: S. aureus strain that produces an enterotoxin. n Reservoir: Human skin, nasal secretions, and cow milk.
• On Manitol salt agar Heamolysis on HBA
Clostridium botulinum n Principal symptoms • Weariness, weakness, vertigo, double vision, difficulty swallowing and speaking n n n Potential food contamination n Improperly canned or fermented goods No. of illnesses n 58 No. of deaths n 4
Clostridium botulinum Botulism & infant botulism (& wound botulism) n The organism – anaerobic, G+ve, spore -forming rod
Clostridium botulinum n Group I – type A, B & F – food spoilage n n Group II – type B, E & F Types A, B, E & F – human botulism Types C & D – botulism in animals Type B is non-protiolytic • Grows in frig at 20 C
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Bacillus cereus n Principal symptoms • Diarrheal—watery diarrhea, abdominal cramps and pain • Emetic—nausea and vomiting n Potential food contamination • Meats, milk, vegetables, fish 0 n No. of illnesses • 27, 360 No. of deaths • 0
Bacillus cereus n Characteristics - rapid growth in food at 30 -400 C - vegetative cells killed by heat - spores resistant, emetic toxins resistant to heat
Harmful algal blooms
What are HABs? n Algae that produce toxins • Dinoflagellates • Diatoms • Cyanobacteria (fresh water) n n Very potent toxins (few cells per liter can produce toxic effects) Adversely affect overall environmental quality
Ciguatera Fish Poisoning n Gambierdiscus toxicus (a dinoflagellate) n n n Associated with weeds and coral reefs Optimum conditions: shallow waters, 25 -34°C, 25 -40 ppt Ciguatoxin and
Ciguatera Fish Poisoning n n Common cause of food-borne poisoning ~ 50% of US seafood poisoning • 90% - Florida and Hawaii • Spring/Summer
Ciguatera Fish Poisoning: Vectors n Usually large fish, bottom dwellers and reef fish • Red snapper, Grouper, Amber Jack, Sturgeon n Toxins • Bioaccumulate • Stable and heat resistant • Lipid soluble • Highly potent (clinical effects from <1 mg)
Ciguatera Distribution
Ciguatera Fish Poisoning: Treatment and prevention n Diagnosis • Biomarkers of exposure not available n Therapy • Not available n Prevention • Complicated n n n Wide range of susceptible species Odorless, colorless, tasteless Avoidance • Large reef fish • Avoiding roe, head, viscera
http: //www. ptccmold. com/images/mycotoxins. jpg http: //cropmonitor. co. uk/images/fusarium. Images/Image 34 Mycotoxins http: //www. knowmycotoxins. com/cn/assets/maninfieldcropped_000. jpg http: //www. ptccmold. com/images/mycotoxin
Poisonous Mushrooms Consequences of ingestion to human health
Classes of Mushroom Toxins n n n PROTOPLASMIC POISONS - CAUSES CELL DAMAGE NEUROTOXINS – POISONS PRINCIPALLY AFFECTING THE AUTONOMIC NERVOUS SYSTEM NEUROTOXINS - POISONS PRINCIPALLY AFFECTING THE CENTRAL NERVOUS SYSTEM GASTROINTESTINAL IRRITANTS OTHER CAUSES OF ILLNESS Amanita phalloides - the death cap
MUSCARINE § § Amanita muscaria - the fly agaric, contains muscarine (an amine) Also found in Clitocybe and Inocybe (little brown and white mushrooms).
The fly agaric - Amanita muscaria
PSILOCYBIN-PSILOCIN Hallucinogenic mushrooms used by Aztecs of Mexico and Central American Indians. n "Magic mushrooms" include Psilocybe coprophila Psilocybe, Panaelous, Conocybe, and Gymnopilus. n
Claviceps Toxins n n Earliest recognized mycotoxicosis caused by C. purpurea, with ergot mold. Outbreaks have been reported since 857 A. D. The Middle Ages had near epidemic proportions. Humans consumed bread baked with grain containing ergot spores, which produced lysergic acid diethylamide (LSD)
Ergot Life Cycle http: //hgca. com/images/upload/Ergot_200810647508. jpg
Ergot Poisoning (St. Anthony’s Fire) http: //www. quizilla. com/user_images • Disease of rye, barley, oats and wheat. • Grains are replaced by ergot sclerotia that contain toxins. • Main toxin is called ergotamine. • Named for the belief that a pilgrimage to the shrine of St. Anthony would alleviate the symptoms. Ergotamine
Ergot Poisoning (Cont. ) • • • Animal symptoms: dry gangrene, internal bleeding, vomiting, constipation, diarrhea, and in pigs: abortion of fetuses. Human symptoms: gastrointestinal stress; convulsions; fetal abortion; extreme burning and cold sensations in fingers, hands, and feet; gangrene of the extremities. Other outbreaks: Russia in 1926, Ireland in 1929, France in 1953, India in 1958, and Ethiopia in 1973.
Aspergillus Toxins • • Large genus with more than 100 species, 50 of which are known to produce mycotoxins. Some of which are aflatoxin, ochratoxin A, sterignmatocystin, cycolopiazonic acid, citrinin, patulin, and tremorgenic toxin. Aspergillus niger is used to make artificial citric acid; one use is in soft drinks. Miso, soy sauce, and sake use strains of A. oryzae. http: //www. cifr. ncsu. edu/aspergillusflavus/home_files/image 006. jpg
http: //www. icrisat. org/aflatoxin/images/aflavus. gif Aflatoxin B-1 • • • Definite link to cancer in animals. Possible link to cancer in humans. Studies done in Africa and Asia show a correlative link, but not a causative one. Primarily attacks the liver, in cases of cirrhosis, necrosis, and carcinomas with a secondary affect of immune suppression. Risk factor for neonatal jaundice, in areas of maternal consumption. Does not stay in the body for long periods of time, usually excreted within 96 hours, in animals. In milk, for human consumption, advisory level
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