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BadBacteriaRevised2010 - Microbes in food Microbes in food...

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Unformatted text preview: Microbes in food: Microbes in food: The good, the bad, and the ugly Respecting our Ancestors Respecting our Ancestors Earth formed 6 billion years ago. Bacteria appear 3.5 billion years. Dinosaurs arrive 250 million years ago, go extinct 65 million years ago. Humans arrive 3 million years ago. Yeast Yeast Yeasts Yeasts Bread Beer Wine Fungi ­ Penicillium Fungi Fungi and Molds Fungi and Molds Positive roles – Flavor in cheese – Oriental fermented foods – Mushrooms Generally spoilage/quality issue – mycotoxins, aflatoxins Viruses Viruses Viruses – alive or not? NOT Infect specific targets – Hoof and mouth­ affects cattle – Plant viruses – Bacteria viruses – Human viruses­concern – Viruses do not grow in food Foodborne viruses Foodborne viruses Norwalk viruses (now Norovirus) – 24­48 h incubation time – 24­48 h duration Hepatitis A – 15­50 day incubation, shedding – Weeks to months duration – 2,000 cases per year Transmission of Foodborne Transmission of Foodborne Viruses The “fecal oral” route Bad water Shell fish from polluted water “Finger licken good” Bacteria Bacteria Modes of Microbial Growth Modes of Microbial Growth Bacteria: Yeast: Molds: Good Bacteria Good Bacteria GENE POOL GENE POOL ESTIMATES FOR FOODBORNE ILLNESS ESTIMATES FOR FOODBORNE ILLNESS US Department of Agriculture 6.5 to 33 million cases/year 5,000 deaths/year 50% Campylobacter, 25% Salmonella Salmonella 4 x 106 cases 1000 deaths Campylobacter 6 x 106 cases 75 deaths Centers for Disease Control 50 cases/100,000 population (125,000 cases/yr) of confirmed diarrhea cases proven as foodborne. Only 1­5% of actual cases reported. ECONOMIC IMPACT = $ 152 billion per year. Philosophies of Microbial Control Philosophies of Microbial Control The 5 K's: Keep it hot. Keep it cold. Keep it moving. Keep it clean. Kill it. Hitchhiker's Guide to the Galaxy: Everything is related to everything else. (Foods are ecosystems) if a farmer puts up fences, for instance Commodity Approach: Know which organisms are associated with which foods and focus on them. Hazard Analysis Critical Control Points ­ Uses 20:20 hindsight and Murphy's Law to our advantage. Cant test all of the food Keep it hot, keep it cold, Keep it hot, keep it cold, keep it moving The importance of time and temperature Modes of Microbial Growth Modes of Microbial Growth Bacteria: Yeast: Molds: The bacterial growth cycle has four phases: The bacterial growth cycle has four phases: log cfu/ml 12 stationary death 8 logarithmic or exponential 4 lag time The Miracle (or curse) of Exponential Growth The Miracle (or curse) of Exponential Growth N = Noekt N = Number of bacteria at any time, t No= Initial number of bacteria k= Rate constant, influenced strongly by temperature, also influenced by environmental conditions In plain English, bacteria grow by doubling: In plain English, bacteria grow by doubling: 1 ­> 2 ­> 4 ­> 8 ­> 16 ­> 32 ­> 64 ­> 128 ­> 256 => 500 ­> 1000 ­> One bacterium can grow to one million bacteria in ___ doublings! Influence of temperature on doubling times: Influence 20 doublings x 20 min/doubling @ 37° = 400 min = 16.5 hours 20 doublings x 1200 min/doubling @ 0° = 24,000 min = 16+ days ( if refrigerated) THE "40­140" RULE THE "40­140" RULE FOODS SHOULD BE HELD: BELOW 40° F OR ABOVE 140°F. COROLLARY: WHEN HEATING OR COOLING, BRING FOODS THROUGH THE 40­140°F REGION AS RAPIDLY AS POSSIBLE. Time and Temperature Time and Temperature Keep it clean! Keep it clean! Keep the microbes out!! Handwashing reduces bacteria Handwashing reduces bacteria (http://users.aol.com/comcontrol/comply.htm) (http://www.asmusa.org/pcsrc/ochsur.htm) Study of handwashing in restaurants, foodservice, healthcare settings show <2 washings per day. FDA estimates poor handwashing contributes to 80 million cases in U.S. 94 % say they wash their hands after using public toilets. 68% observed wash their hands after using public toilets. Cross-contamination Bacteriological Survey of Bacteriological Survey of Sponges and Dishcloths (Enriquez, et al., Dairy Food Environ Sanitarian 17:20­24) Organism Total Coliforms Fecal Coliforms Salmonella Staphylococcus Sponge 5 1 x 10 2 4 x 10 15% 20% Cloth 5 1 x 10 3 2 x 10 20% 19% Top Ten Causes of Outbreaks Top Ten Causes of Outbreaks (Snyder, J. Food Service Systems 6:107­139) Activity Involvement 1. Improper cooling 43.7% 2. Greater than 12 hours between preparing and eating 22.6% 3. Colonized person handling implicated food 18.1% 4. Incorporating raw food/ingredient into foods that received no further cooking 15.8% 5. Inadequate cooking/canning/heat processing 15.5% 6. Improper hot handling 13.3% 7. Inadequate reheating 10.6% 8. Obtaining food from unsafe source 10.0% 9. Cross contamination 5.4% 10. Improper cleaning of equipment/utensils 5.4% Old Model ­ Safety At Some Place Old Model ­ Safety At Some Place (Do What Government Tells You) Example: Low Acid Foods Pinpoint Problem Provide Solution Promulgate Regulation Punish Violators Regulatory Agencies Regulatory Agencies USDA ­Meat and Poultry ­Continuous inspection ­Department of Agriculture FDA ­Everything else ­Periodic inspection ­Department of Health and Human Services ­Food and Safety Modernization Act Center for Disease Control and Prevention (Epidemiology but no regulatory authority) Also Bureau of Alcohol Firearms and Tobacco New Model ­ Safety Depends on Whole System “Farm to Fork” (Achieve Government Dictated Outcome) Seed Soil Fertilization Agricultural practices Climate Harvest Storage Transportation Processing Distribution Supermarket Home Preparation Consumption Human Biology Food Safety from Farm to Table Food Safety from Farm to Table s Focus on hazards that pose greatest risk (risk assessment) s Increased inspection (rapid methods) HACCP s Research, training, education “Fight Bac” “Don’t get Caught Dirty Handed” s HACCP ­ Hazard & Control HACCP ­ Hazard & Control 1. Conduct a Hazard Analysis Identify chemical, biological and physical safety hazards likely to occur and how they can be controlled. 2. Determine Critical Control Points (CCPs) Steps at which hazard can be reduced. 3. Establish Critical Limits Maximum and/or minimum value to which a parameter must be controlled to prevent hazard. (i.e. 68 C, 16 s for precooked hamburger) HACCP ­ Monitoring & Documentation HACCP ­ Monitoring & Documentation 4. Establish Monitoring Procedures Observation/Measurement of CCP in “real time” to determine and document control. 5. Establish Corrective Actions Correct the deviation, disposition of product, documentation. 6. Establish Verification Procedures How do you know: that HACCP is working? that the assumptions of Steps 1­3 are still valid? 7. Establish Record Keeping and Documentation For the HACCP System Miscellaneous issues Miscellaneous issues Reflections on pyramid, grading My “pyramid” No “extra help” or extra credit at this point, but will try to recap lectures Major points from last lecture: Major points from last lecture: Our place in the biosphere Bacteria, yeast, molds and viruses are different­ how? Which cause food­related illness? By what route? Extend of problem, cases, deaths, costs Philosophies of control What is HACCP? Exponential growth – no numerical solution for equation, but understand “doubling” Two most important factors in food safety “Farm to fork” Different from chemical, no NOEL concept Staphylococcus aureus Staphylococcus aureus Associated with poor sanitation, poor personal hygiene Makes heat resistant, fast acting toxin Organism killed by heat, toxin not killed Staphylococcus aureus Case Study Staphylococcus aureus Flight from Tokyo to Copenhagen via Anchorage 196 of 343 passengers, 1 of 20 crew food eaten: 1 h post Anchorage, snack, served to all 5.5 h post Anchorage, steak dinner, crew 5.6 h post Anchorage, cheese omelet w/ ham passengers only onset: 0.5 to 5.5 h after breakfast, average 2.5 h symptoms: diarrhea (88%), vomiting (82%) cramps (74%), nausea (68%) Clostridium botulinum Clostridium botulinum Makes heat­resistant spores Makes lethal, but heat sensitive toxin Grows without air Potential agent for biological warfare BOTULISM BOTULISM TRADITIONAL ETIOLOGY: Botulism attributed to ingestion of toxin from improperly processed low­acid canned foods BOTULINAL TOXIN CAN ALSO BE FORMED IN: ­Temperature abused foods ­Gastro­intestinal tract, “infant” botulism Botulism and Temperature Abused Pot Pie Botulism and Temperature Abused Pot Pie (Morbidity and Mortality Weekly Report, Vol. 32, # 3) Patient: 56 year old diabetic woman Symptoms: diplopia, weakness, difficulty breathing, chest pain, respiratory arrest. Scenario: Son prepared pot pie for mother. Father brought home take­out hamburgers. Mother left pot pie out on shelf (in California, in August), and ate it two and one­half days later without reheating. Illness: next day. Type A botulinum toxin was isolated from the left­over food and patient's serum. Salmonella spp. Salmonella Increasing antimicrobial resistance. Large and dispersed outbreaks. Habitat is the intestinal tract of animals. 49% of animal feed contaminated. 15­30 % of poultry contaminated (threat of cross contamination). More major points from last lecture More major points from last lecture Why are there new pathogens?­think of logic, don’t memorize list Refrigeration­temperature abuse, refrigerators Importance of pasteurization (kills pathogens), soft cheese, industrial use of eggs. Raw milk is dangerous Role of CDC “listeria” versus “listeria monocytogenes” – Listeria monocytogenes is the one that is the killer S. Enteritidis in eggs Colonizes ovaries. Internal contamination of egg. May penetrate egg shell during cooling. Capable of multiplication in egg yolk or albumen. Generally low numbers recovered. Low % of samples are contaminated (0.04%) (How do you test for this?) S. enteritidis S. enteritidis Outbreak 1994, 224,000 persons in U.S. develop S. enteritidis gastroenteritis after they ate ice cream. Contamination was linked to transport of pasteurized ice cream premix in tanker trailers that had previously carried nonpasteurized liquid eggs. (Cross­contamination.) CONTROL CONTROL Cook eggs thoroughly (Pass a Law) Avoid cross­contamination Employ proper refrigeration CONTROL ON THE FARM Campylobacter Campylobacter Campylobacteriosis more common than salmonellosis. Higher morbidity, lower mortality. Infective dose can be small. 30­70% of all chickens infected. Congressman John Dringle Congressman John Dringle states…. Foodborne illness has increased, so has the volume of food coming into our country…. More than 38% of fruit and 12% of vegetables Americans consume are imported, yet less than 2% is inspected by the FDA and less than 0.2% is tested for microbiological contamination. Cryptosporidim protozoa usually municipal water supply, also splash parks. Guatemalan raspberries (5) Why do "new" pathogens emerge? Why do "new" pathogens emerge? (Lynton Cox, Food Technol. 43(12)52­59) 1. CHANGES IN EATING HABITS 2. CHANGES IN AWARENESS 3. CHANGES IN DEMOGRAPHICS larger sensitive populations of at risk people 4. CHANGES IN FOOD PRODUCTION scale of operation, global production 5. CHANGES IN FOOD PROCESSING TECHNOLOGY. 6. CHANGES IN HANDLING AND PREPARATION 7. CHANGES IN BACTERIA, plasmids, horizontal gene transfer Bad News on Refrigeration Bad News on Refrigeration Hutton, et al., 1991, J Food Safety 11:255­267 15 CITY ­ 100 SUPERMARKET STUDY OF REFRIGERATOR CASES 90% OVER 40°F 20% OVER 50°F Woodburn, J. Am. Diet. Assoc. 87:322­326 21% OF HOME REFRIGERATORS OVER 50°F Listeria monocytogenes­disease syndromes Listeria monocytogenes­ 1. Low grade "flu­like" infection ­ not serious, except in pregnant woman (who abort). Up to 16% women carry L. monocytogenes without illness. (Larmont and Postlethwaite, 1986, J. Infection 13:187­193.) 2. Listeric meningitis­ headache, drowsiness, coma. 50% fatality rate. If very young and old are excluded, this drops to 30%. 3. Perinatal infection ­ 0.15% to 2.0% of all perinatal mortality. 4. Encephalitis 5. Psychosis 6. Infectious mononucleosis 7. Septicemia Los Angeles Mexican Soft Cheese Los Angeles Mexican Soft Cheese ­ 93 Perinatal cases: 19 Still births 10 Postnatal deaths ­ 49 Adult cases: 18 Deaths ­ Linked with Mexican soft cheese ­ Same type isolated from cases and processing plant ­ Plant's milk output exceeded capacity of pasteurizer Risk for Listeriosis Risk for Listeriosis Southwick & Purich, New Eng. J. Med. 334:770 General Population Over 70 years old Pregnant H.I.V. positive 0.7 cases /100,000 3 times higher 17 times higher 100 ­ 300 times higher “Sara Lee” Outbreak (Bil Mar, Ball Park franks) 79 illnesses in 17 states 12 deaths, three miscarriages 35 million pounds of product recalled Recall costs (to Sara Lee) $50­70 million Stock price falls from $55 to $25 (over 4 months) Pilgrim's Pride Recall Pilgrim's Pride Recall 27 MILLION pounds of turkey and chicken meat recalled in Metro Philadelphia. L. monocytogenes L. monocytogenes acute gastroenteritis (the exception) 1994 OUTBREAK 45 people at picnic become ill Bedridden, 4 hospitalized Diarrhea (79%) Fever (72%) 75% attack rate Onset = 9­32 h (median = 20 h) 60 Minutes segment, points: 60 Minutes segment, points: Role of CDC in discovery and multistate involvement USDA inspector Generic “listeria” vs. Listeria monocytogenes Size of recall Personalization E. coli O157:H7 E. coli Disease – Onset 5 to 7d following ingestion – Hemorrhagic colitis Blood in stools Severe abdominal pain Some vomiting No fever E. coli O157:H7 • Disease – Hemolytic uremic syndrome (HUS) • Blood clots block tubules in kidney resulting in accumulation of waste products • Renal failure in children – Thrombotic thrombocytopenic Purpura (TTP) • Decrease number of platelets • Spontaneous hemorrhages beneath the skin • Blood clotting in brain Issues in Produce Safety Issues in Produce Safety Lettuce, Tomatoes, Sprouts, Almonds, Peanuts, Pistachios, Spinach E. coli O157:H7 local outbreak E. coli Big local news story Time between outbreak and discovery Action by municipal officials Questionable remediation Interviews with “locals” “Sound bite” – “We don’t live in a sterile world.” Listeria monocytogenes­ disease Listeria monocytogenes­ disease syndromes 1. Low grade “flu­like” infection­ not serious, except in pregnant woman (who abort) 2. Listeric meningitis­headache, drowsiness, coma– 50% fatality rate. If very young and old are excluded, this drops to 30% 3. Perinatal infection 4. Encephalitis 5. Psychosis 6. Infectious mononucleosis Risks for Listeriosis Risks for Listeriosis General Population­­­.7/100,000 Over 70 years old ­­­ 3 times higher Pregnant ­­­17 times higher H.I.V. positive Bio­terrorism is a Real Concern Bio­terrorism is a Real Concern Assault on animal agriculture Assault on agricultural crops Use of processed food as terror tool – By individual – Organized terrorist group Bio­terrorism Defined Bio­terrorism Defined Osterholm, Emerging Infections 5, p 213, 2001 “the use of biological agents to intentionally produce disease or intoxication in susceptible populations to meet terrorists’ aims” Morbidity, Mortality, Economic Loss, Sheer Terror Food Bio­terrorism Food Bio­terrorism Low tech High impact Inexpensive Hits “at home” Easy to transport Hard to detect (before or after) Unlike chemical or radiological threat Bacterial Agents Bacterial Agents Clostridium botulinum, or its toxin Staphylococcus aureus, or its toxin Salmonella enteriditis or typhi E. coli O157:H7 Bacillus anthracis Accidental: Accidental: 250,000 cases of salmonellosis 100 cases of listeriosis 100 cases of listeriosis Could have just as easily been caused by bio­terrorist. Bio­terrorism in Oregon, 1984 Bio­terrorism in Oregon, 1984 Salmonella Typhimurium 751 cases, 45 hospitalizations Intentional contamination of salad bars Rajneeshee cult seeking electoral influence Not identified as bio­terrorism until two years later Operational Risk Operational Risk Management (Food Safety and Security: Operational Risk Management Approach, Nov. 26, 2001; www.cfsan.fda.gov) Operational Risk Management Operational Risk Management 1. Identify the Hazards ­ what if? 2. Assesses the Risk –hazard x severity 3. Analyze Risk Control Measure, includes risk/benefit mitigate, eliminate, delay, transfer 4. Make Control Decision – what will we do? 5. Implement Risk Controls – inform, motivate 6. Supervise and review – inspect, interview, quiz “Guidance for Industry Food Producers, Processors, Transporters, and Retailers: Food Security Preventive Measures Guidance” ­FDA Guidance for Industry Guidance Management of food security Physical security Employees Computers Raw materials Air and water Finished product Finished Product Finished Product Keep track of it – missing or extra stock Warehouse and transportation security Monitor food in open display areas Counterfeiting FDA Food Bioterrorism Act of FDA Food Bioterrorism Act of 2002 The Public Health Security and Bioterrorism Preparedness and Response Act of 2002 Components of the Act Components of the Act 1. Registration of Facilities – by Dec 12, 2003 Factories, warehouses, “establishments,” must register even if regulation not issued. Food service and nonprofits exempt. 2. Record Keeping – need to ID previous and subsequent holder of the food. Records allow FDA to address credible threats. Entities that manufacture, process, pack, transport, distribute, receive, hold, or import are subject to these rules. 3. Prior notice – of importation. At least 8 h, but not more than 5 days, in advance. ...
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