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Transcript
Foodborne Disease Part Tres Food Intoxications • Toxins not destroyed by cooking. • Appears more rapidly than food infections Bacillus cereus • Intoxication or toxinmediated • Spore forming • Facultative • Vomiting, diarrhea Symptoms and Onset Time • 30 minutes to 6 hours (vomiting) • 8-16 hours (diarrhea) Common Foods • Rice, potatoes, • Also meats, milk, vegetables, fish Pasta • Made from soybeans, water and a coagulant, or curdling agent. • Coagulating soy milk, and then pressing the resulting curds into blocks. • High in protein and calcium Tofu • Staple of Asian cuisines for hundreds of years • Recently become popular in Western vegetarian cooking. Tofu is… • low in calories • contains beneficial amounts of iron (especially important for women of child bearing age) • no cholesterol Depending on the coagulant used in manufacturing, the tofu may also be high in calcium (important for bone development and maintenance), and magnesium (especially important for athletes). Transmission of Bacillus Cereus • Improperly stored (cooled, hot held) • Allows conversion of spores to vegetative cells • Vegetative cells produce the toxins • Toxins lead to illness Prevention • Cooked and held at 135°F • Cooled to 41°F (rapidly) Clostridium perfringens • Anaerobic, spore-forming • 24 hour flu • Toxin-mediated infection (ingested cells colonize and then produce a toxin in the intestinal tract) Symptoms and Onset Time • Abdominal pain and diarrhea • Onset 8 to 22 hours Common Foods • Meats (boiled, steamed stewed, braised or insufficiently roasted) • Improperly cooled • Improperly reheated • Institutional feeding (school cafeterias, hospitals, nursing homes, prisons, etc.) where large quantities of food are prepared several hours before serving. • The young and elderly are the most frequent victims of perfringens poisoning. Transmission • PHFs temperature abused • Improperly cooled • Improperly reheated Example • 10 gallon pot of chili prepared for next days lunch (beans, meats, spices tomato base) • Cooked to boil • Vegetative cells die, but spores may survive • Chili stored in 10 gallon pot • 3 days to cool Prevention • Cooked adequately • Cooled from 135°F to 70°F (2 hours) then • 70°F to 41°F (4 hours) • Reheated rapidly to 165°F • Reheat one time Cooling Foods Quickly • Cut large items (roast, ham or turkey) into smaller pieces. • Ice water bath • Shallow containers • Do not stack pans • #1 cause of FBI Staphylococcus aureus • • • • Facultative anaerobic Foodborne intoxication Heat stable Grows on cooked foods • Do not compete well when other microbes are present. • Found on human skin, hands, hair, nose and throat. • Burns, infected cuts, pimples, boils • Grow in foods with high salt or high sugar and low Aw. Symptoms and Onset Time • Severe nausea, acute abdominal pain, vomiting, diarrhea • Onset time: 1 to 6 hours • Last 1-2 days Common Foods • Cooked, RTE foods (luncheon meat, egg salad, vegetable salads) • Ham (high salt) • Milk and dairy products Transmission in Foods • Humans are primary reservoir • Hands • Droplets of saliva (coughing, sneezing near food) • Tasting foods (spoons) Prevention • • • • • No bare hand contact Employees with cuts Handwashing Reuse “tasting” spoons Danger zone People are the prime source of Staph. • Healthy adults carry Staph in their noses and skin. • Foodhandlers must be conscious of what they touch and to wash hands frequently. Clostridium botulinum • Anaerobic, spore-forming • Foodborne intoxication • Improperly heated processed foods (especially home canned) • Produces a neurotoxin • Not heat stable Symptoms and Onset Time • Fatigue, headaches, dizziness • Inability to swallow • Respiratory paralysis • Onset time 12-36 hours • Several days - year Common Foods • Low acid foods (pH 4.6), inadequately heat processed, packaged anaerobically (canned or vacuum pouch) • Held in the danger zone • Sautéed onions, Patty Melt sandwich (Illinois) • 28 victims (1 died) • Louisiana – foiled wrapped baked potato • Left out overnight Transmission Ingestion of food that were not heat processed correctly and packaged anaerobically. Canned Foods – Swollen ends – Leaks and flawed seals – Rust – Dents Foodborne Disease Viruses What are viruses? • not a bacterium • not an independently-living organism • cannot survive in the absence of a living cell within which to synthesize copies of itself (replicate). • Unlike living organisms, cannot reproduce independently • But like living organisms, can reproduce. • Has some fundamental information which allows it to make copies of itself. • Must be inside a living cell Even though the smallest viruses are only about onemillionth of an inch long, they live up to their Latin namesake—poison. Foodborne Illness Caused by Viruses • Smaller than bacteria • Require a living host • Do not reproduce or grow in foods Percentage of Foodborne Illness Attributable to Known Pathogens Bacteria 30% Protozoa 3% Mead et al., 1999 Viruses 67% • Usually transferred from one food to another from food handler or contaminated water supply. • PHF not needed to support survival • RTE foods most frequently associated with viral infection. • Viruses usually have a tough outer covering. • Can survive on surfaces for several seconds up to a couple of days. Viruses also are more likely to remain dangerous on hard or non-porous surfaces than if they are on porous surfaces. 3 Viruses • Hepatitis A • Norwalk virus • Rotavirus Handwashing is the key! Hepatitis A • Viral infection • Causes a liver disease (infectious) • Food worker can harbor disease for up to 6 weeks w/o symptoms • Food workers are infectious one week before onset of symptoms Hepatitis A continues to be one of the most frequently reported vaccine-preventable diseases in the United States. From 1980 through 2001, an average of 25,000 cases each year were reported to the Centers for Disease Control and Prevention (CDC) However… • Underreporting • Asymptomatic infections • Estimated average of 263,000 HAV infections occurred per year The 411 • Liver disease caused by the hepatitis A virus. • Can affect anyone. • Can occur in situations ranging from isolated cases of disease to widespread epidemics. • Good personal hygiene and proper sanitation can help prevent hepatitis A. • Vaccines- for long-term prevention of hepatitis A virus infection in persons 12 months of age and older. Symptoms and Onset Time • Fever, nausea, vomiting, abdominal pain, fatigue • Swelling of liver, jaundice (yellow skin) • Onset time: 15-50 days • Last several weeks – several months Common Foods • infected food worker preparing salads • lunch meats, salad bar items • sandwiches, bakery items. Raw oysters, clams harvested from polluted waters. Raw vegetables irrigated or washed with contaminated water. Transmission in Foods Ingestion of food and water that contains the Hepatitis A virus. • …has been traced to diversed foods (donuts, strawberry sauce, sandwiches, salads. • Virus shed in urine, feces (poor personal hygiene) Can lead to liver damage. HAV contamination of a food product can occur at any point during cultivation, harvesting, processing, distribution, or preparation. The source of most reported foodborne hepatitis A outbreaks has been HAV-infected food handlers present at the point of sale (such as in a restaurant) or who prepare food for social events (such as a wedding). A single HAV infected food handler can transmit HAV to dozens or even hundreds of persons and cause a substantial economic burden to public health. In Da’ News…..Transmission during growing, harvesting, processing, or distribution. HAV-contaminated frozen strawberries were implicated as the source of an outbreak involving at least 262 persons in 5 states. HAV-contaminated shellfish Factors Inappropriate or illegal shellfish harvesting near known sources of sewage. Inappropriate discharge of sewage from fishing boats or oil platforms near shellfish beds. Fecally contaminated water & harvested live shellfish. Prevention • Handle foods properly • Cooked to proper temperature • Avoid eating raw seafood • Wash hands and fingernails thoroughly after using the toilet. Mandating proof of vaccination for food handlers or offering tax credits for food service operators who provide hepatitis A vaccine to employees have been implemented in some areas. Also need to… • Encourage ill foodhandlers to seek medical attention and to stay out of the workplace. • Exclusion from duties that involve contact with food for at least 1–2 weeks after the onset of jaundice or until symptoms resolve is reasonable. Providing sanitary facilities for field workers and discouraging the presence of children in areas where food is harvested reduces the potential for contamination of food during harvesting or processing. Chlorinated water or water from a source not likely to be contaminated by sewage should be used for rinsing produce or ice used for packing. However Other than thorough cooking, no reliable disinfection method for shellfish exists. Reducing HAV contamination of foods should be possible using approaches, such as Hazard Analysis and Critical Control Point (HACCP) systems. Haccp HAZARD ANALYSIS CRITICAL CONTROL POINTS The Flow of Food RECEIVING STORAGE PREPARING COOKING HOT HOLDING SERVING COOLING RE-HEATING Handwashing is critical Handwashing 101 Wet Hands Apply Soap Rub Hands for 20 sec. Rinse Well Dry with Paper Towel Turn off w/paper towel Open Door w/towel Norwalk Virus • Viral infection • Viruses of the Norwalk type are now classified as noroviruses. In Da’ News.. • Large outbreaks of gastroenteritis which occurred in Pennsylvania and Delaware in 1987 were caused by Norwalk virus. • A contaminated well was the source of both outbreaks. In Pennsylvania, the ice was used at a football game and at a cocktail party in Delaware. Symptoms and Onset Time • Nausea, vomiting, diarrhea, abdominal pain • Headache, low grade fever • Onset : 24-48 hours • 1-3 days Common Foods • Sewage contaminated water • Shellfish • Raw clams or oysters • Food handled by ill food handlers Transmission in Foods Ingestion of food and water that has been contaminated with feces that contain the Norwalk virus. Prevention • • • • Potable water Proper cooking Proper handling Avoid raw seafood Pathogens with Extremely Low Infectious Dose Hepatitis A virus ~ 10 or less viral particles Norovirus ~ 10 to 100 viral particles EHEC is as low as 10 bacterial cells Shigella spp. can be as low as 10 bacterial cells S.Typhi is considered low ~ 1000 bacterial cells Potential Transmission Level Norovirus Shed in the feces at levels up to 10,000,000 viral particles per gram of feces. • One projectile vomiting incident can potentially contaminate the environment with 30,000,000 viral particles • Infectious dose of NoV is estimated from 10-100 viral particles Transmission of Norovirus • • • • Fecal-Oral Route Airborne Inhalation Person-to-Person Environment-to-Person Norwalk Virus • 1st recognized in a school outbreak in Norwalk, Ohio. (1968) • Water was suspected. Cake frosting and salads, as well as drinking water, have been implicated as a common source of viral infection in several outbreaks. Norwalk and Norwalk-like viruses also are referred to as "noroviruses." infection symptoms include nausea, vomiting, diarrhea and abdominal cramps. NV vs. Duke University & Florida State Football Teams . . . Norovirus Won • 9/18/98: Duke Univ. football team ate turkey sandwiches prepared by ill food employee • 9/19/98: Duke team players - suddenly ill during game, w/ vomiting & diarrhea; continued to play NV crossed the line of scrimmage – Transferred via football & player’s hands – 11 FSU players became sick • 1st documented case of person-to-person transmission of NV at sports event • In most people, the illness lasts for about one or two days. People with norovirus illness are contagious from the moment they begin feeling sick until at least three days after they recover. • Infection can be more severe in young children and elderly people. Dehydration can occur rapidly and may require medical treatment or hospitalization. Rotavirus • Viral infection • Rotavirus gastroenteritis • Lead cause of severe diarrhea among infants and children. • When a Rotavirus infects a human being it affects the cells in the digestive tract causing severe diarrhea. • Pediatric diarrhea caused by this Rotavirus is directly responsible for the death of 1 million children around the world. • Rotavirus is very easy to catch. • Large amounts of rotavirus are shed in the stool. Remember… viruses • • • • Do not multiply in food. Small infectious dose Poor personal hygiene Sewage polluted water • Need a living cell to reproduce • Do not require PHF to get around • Some survive freezing and boiling GOOD PERSONLAL HYGIENE it the best prevention against viruses! The Inn Check Bb! Wash Yo’ Hands!!