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
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
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.
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
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
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
5 1 x 10
4 x 10
5 1 x 10
2 x 10
19% Top Ten Causes of Outbreaks Top Ten Causes of Outbreaks
(Snyder, J. Food Service Systems 6:107139) Activity Involvement 1. Improper cooling
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
Meat and Poultry Continuous inspection
Department of Agriculture FDA
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
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
onset: 0.5 to 5.5 h after breakfast, average 2.5 h
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 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.
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
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
– 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
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:
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
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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- Fall '08
- Escherichia coli, Platelet, Coliform bacteria