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92 Cards in this Set
- Front
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- 3rd side (hint)
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Water activity
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ratio of the vapor
pressure of the air in equilibrium with a substance to the vapor pressure of pure water. |
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Water activity in food ranges between ...
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0 and 1
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Moisture content
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the amount of moisture
present in the product |
Stable, non-perishable foods have a low moisture
content; when subjected to moisture there is a change in their stability. |
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Water Activity (aw) equation
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aw = p/ps
. Where p = partial pressure of water vapor at the surface of the product . ps = saturation pressure |
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Relative humidity (RH)a
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%RH = p/ps x 100
. Where p = partial pressure of the water vapor present in the gas mixture . ps = saturation pressurety. |
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Example values:
aw material Water, Sea water Bread, Salami Salted fish Dried fruit/cereals |
1.00 pure water
0.98 sea water 0.95 bread 0.85 salami 0.75 salted fish 0.70 dried fruit, cereals |
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Different foods are colonized by different
organisms that can... |
use its nutrients
. Enteric organisms colonize meats, but rarely fruits (unless subjected to fecal contamination) . Pseudomonas, common in water and soil, is found as a spoilage organism in fresh foods |
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Microbial Rate of growth on food depends on
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Temperature
Nutrient value of the food |
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Time needed to reach concentration
necessary to cause adverse effects |
Size of inoculum
Rate of growth |
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Processes to slow/prevent the growth of
microorganisms in foods (6) |
Temperature
Acidity Lower water activity Canning Chemicals Irradiation |
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Temperature has what effect on microorganisms?
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Lower storage temperature = slower growth
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cold tolerant; grows at refrigeration
temperature known as ... |
Psychrotolerant
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Acidity has what effect on microorganisms? (what pH below?)
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Acid used to �pickle� food. pH 5 = inhibit spoilage Stop organisms metabolism.
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Lower the water activity: Three ways:
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Add salt.
Add sugar. Drying/lyophilization (freeze drying). |
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Canning has what effect on microorganisms?
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Placing foods in jars or cans and heating them to a
temperature that destroys microorganisms. During heating air is driven out of the jar and as it cools a vacuum seal is formed . Vacuum seal prevents air from entering product bringing with it contaminating microorganisms . Stored in absence of refrigeration |
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Two safe processes for canning food: (which is better and why?)
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the boiling water bath method
and the pressure canner method. Pressure canner method is best (boiling can method may allow anaerobic orgs to survive: i.e. botulism and/or toxin) |
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Antimicrobial Chemicals do what for food:
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Inhibit microorganism growth. Preservatives. Examples: Sodium/Ca propionate, Na benzoate.
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FDA GRAS stands for
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Food and Drug administration: Generally recognized as safe.
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Irradiation is/does
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controled doses of gamma rays. Destroys organism DNA (irreparable). Used on packaged or canned food.
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Foodborne disease categories (how the diseases are released): (3)
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Biomisfortune (? = third side)
Biocrime/biomisdemeanors(?) Bioterror/Biowarfare |
Biomisfortune
. Naturally occurring foodborne disease . Virtually all foodborne disease falls in this category . A daily concern of public health departments Foodborne Disease Types 2. Biocrime and biomisdemeanors . Intent to harm for personal gain or revenge . A few dozen events in recent decades 3. Bioterror and biowarfare . State-sponsored or hate group terrorism |
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Microorganisms can cause disease in three ways:
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Toxins from plants/alge/fungus.
Microbial infection. Bacterial toxins. (examples: third side) |
Mushrooms �V amanitas type (1-2 bites can be
fatal to an adult) �� Water hemlock �V most toxic of all North American plants; Cicutoxin - no antidote, death in 30% of reported poisonings �� Castor bean �V ricin toxin (Select Agent) �� Jimsonweed �V poisonous seeds, leaves and nectar Ergot - mold infects grain �� Aflatoxin - toxin produced by mold growing on nuts and grains; potent carcinogen �� Certain fish and shellfish . Ciguatoxin: reef and rocky bottom fish, algal toxin . Scombroid poisoning: deep sea fish, bacterial toxin . Paralytic shellfish poisoning: shellfish, algal toxin 2. Microbial infection e.g., brucellosis, Campylobacter enteritis , listeriosis, salmonellosis, toxoplasmosis, trichinellosis, infection with vibrios, E. coli , hepatitis A, shigellosis, viral gastroenteritis 3. Bacterial toxins . produced in the food before consumption e.g., Clostridium botulinum, Staphylococcus aureus . produced in the intestines e.g., Clostridium perfringens |
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Food poisoning is otherwise known as ... and is ..
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Food poisoning (food intoxication)
. toxin produced by microorganism in food . toxin ingested |
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Food infection
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microorganism ingested and reproduces in host
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Food intoxication
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The microorganisms grow in food and
produce toxin �� Do not necessarily grow in the host and may not be alive when the food is ingested �� Preformed bioactive toxin �� Important Bacterial Intoxications . Staphylococcus aureus �V enterotoxin in food not destroyed with cooking . Clostridium botulinum - produces deadly neurotoxin (heat labile)� |
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Staphlococcus aureus:
Signs/symptoms Virulence factors do ... Dx, Tx, prevention: |
Signs and symptoms
. Nausea, vomiting, diarrhea, cramping . Pathogen and virulence factors . Caused by Staphylococcus aureus . Virulence factors include five enterotoxins . Pathogenesis and epidemiology . Outbreaks associated with social functions . Diagnosis, treatment, and prevention . Diagnosis based on signs and symptoms . Treatment based on fluid and electrolyte replacement . Proper hygiene can reduce incidence |
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S. aureus transmission
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�� Reservoir
. Humans �V approx. 25% - 35% of healthy individuals are carriers of S. aureus . Occasionally cows, dogs, fowl �� Transmission . Foods that come in contact with food handler��s hands �G Without subsequent cooking �G Inadequate heating or refrigeration |
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S. aureus: general info:
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Gram-positive cocci, arranged in clusters
�� Non-motile �� Facultative �� Tolerate drying, high salt (low aw) �� Often pigmented c= |
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S. aureus: percent of intoxication cases US:
Sources: Onset of symptoms time: |
�� 20-40% of all food intoxication cases
(est.185,000 cases/yr in U.S.) WHAT WENT WRONG? (third side) �� sources . cream pies . sauces . gravies . cooked ham . chicken/egg salad . pastries . food held at improper temperature �� onset of symptoms . 2-4 hrs avg. . early as 30 min |
These foods are often kept at room
temperature or outdoors at picnics �� Staphylococcus , if present as a contaminant, proliferates, producing enterotoxins �� Refrigeration slows growth of Staphylococcus �� Toxins are relatively heat stable . several stable at the boiling point . re-heating food not effective |
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S. aureus: Enterotixins (5 sort of).
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Seven different toxins
. A, B, C1, C2, C3, D, and E . A - most often implicated in foodborne intoxication . Stimulates T cells that release cytokines, activating a general inflammatory response in the intestine leading to gastroenteritis with massive fluid loss from the intestine ONSET (third side) ILLNESS, Severe Tx |
Short period before symptoms �V range 30
min to 6 hrs (Why?) �� Illness can be severe . Profuse vomiting (may have blood) . Nausea . Abdominal cramps . Diarrhea (may have blood) �� Self-limiting, resolves 48 hours after onset �� May require treatment for dehydration �� Antibiotic treatment not useful (Why not?) |
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S. aureus: Dx
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Illness usually self-limiting; hospitalization
rare �� Diagnosis in outbreak settings . Culture of S. aureus 105/g of food . Detection of enterotoxin �� Absence of culturable staphylococci does not rule out diagnosis �� Diagnosis can be confirmed by isolation of same species type from human stool �� Typing, enterotoxin tests not routinely available |
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S. aureus: Control measures
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Educate food handlers
. Food hygiene . Dangers of working with exposed skin, nose or eye infections, and uncovered wounds . Reduce educe food handling times (4 hr max), store/cook at proper temperatures . Exclude workers with infections of hands, face or nose . Discard food if kept above 4��C for > 2hrs |
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C. botulinum: about
how may/year US (%mortality) |
Anaerobic, gram positive endosporeproducing
bacilli �� Common inhabitants in soils �� Endospores are heat stable ��Spores germinate and toxin is produced. Approx. 50 cases/yr in US . ~25% fatal |
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Botulism is ...
Signs/symptoms ... causitive agent (and spelling!) |
Signs and symptoms
. Caused by intoxication from ingested toxin . Three primary forms . Food-borne botulism . progressive paralysis of all voluntary muscles Botulism . Infant botulism . bacteria grow in the intestines, producing non-specific symptoms . Wound botulism . symptoms like those of food-borne botulism . Pathogen and virulence factors . Clostridium botulinum is the causative agent . Different strains produce one of seven neurotoxins . Four types cause human illness |
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Botulism:
epidemiology ... Most commonly affects ... Dx, Tx, prevention ... |
Epidemiology
. Rare, roughly 50 cases of food-borne and wound botulism per year in U.S. . Infant botulism most common form in U.S. . Diagnosis, treatment and prevention . Diagnosis . flaccid paralysis, neurological symptoms Botulism . Three approaches to treatment . Washing of intestinal tract to remove Clostridium . Administration of botulism immune globulin . Treatment with antimicrobial drugs . Prevention - destroying endospores in contaminated food through proper canning techniques� |
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Botulism toxin:
LD50 ... Does ... |
One of the most lethal substances known
�� Lethal dose (LD50) = 1ng/kg of body mass�� Inhibits ACH production at neuronal cleft. |
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Botulism affects ______ (human sub-population)
Through ingestion of ____ (food product) which contains ____ (organism/state). Prevent by ____. |
infants
Honey (or improperly canned foods) C. botulinum (spores) Prevent by waiting until infant gut flora sufficient to fend off organism (~6 mo.) |
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C. perfringens
Food Intoxication: Dose ... Commonly found in what foods ... Why? |
Disease caused by ingestion of large dose
. >105 cells Contaminated and inadequately cooked foods C. perfringens . Food Intoxication . Meats, esp. cooked in bulk . Poultry . Fish . Insufficient heating and then holding at 20-40��C . Organisms present, but no toxin yet ONSET (THIRD SIDE) |
7-15 hours after consumption
. Cells begin to sporulate in the intestine . Triggers production of toxin . Alters permeability of epithelium . Results in diarrhea and cramps . NO vomiting, NO fever . Symptoms resolve within 24 hours; self-limiting . Rarely fatal |
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C. perfringens
When seen (time of year) ... Pre-cooked food is dangerous because ... |
Often seen in the fall and winter months
�� Institutions and large gatherings with large scale meat cooking �� High attack rate �� Also demonstrated when food is pre-cooked and then re-heated . spores resist first heating, germinate in the food and proliferate, second heating is inadequate, cells are ingested �V sporulate in intestine, produce toxin . Ex) baked potatoes wrapped in foil re-heated the next day caused outbreak �V food chainp > |
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C. perfringens commonly found in ... (3)
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Common in soil
�� Also lives in the intestinal tract of many animals . found in sewage �� May contaminate food products at harvest and at preparation . Agricultural practices . Food handlers |
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C. perfringens Dx
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Isolating C. perfringens from anaerobic
cultures of food or stool �� Demonstrating toxin in stool �� No treatment is usually given |
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Food infection definition
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Active infections resulting from ingestion of
food with microbial contaminants present �� May or may not have a toxin componentiven9AD |
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Campylobacter - Diarrhea
Caused by ... about org ... Pathogenisis/epidemiology .. Dx, Tx, prevention ... |
Pathogen and virulence factors
. Caused by Campylobacter jejuni . Gram negative rod-shaped bacterium . Virulence factors include adhesins, cytotoxins, endotoxin Campylobacter Diarrhea . Pathogenesis and epidemiology . Virulence factors produce bleeding lesions and trigger inflammation . Diagnosis, treatment, and prevention . Diagnosis based on signs and symptoms . Most cases resolve without treatment . Proper hygiene after handling raw poultry |
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Campylobacter is the ___ type of food infection.
Typically found in _____ (5) Onset of symptoms ... ___% develop long term problems/complications. |
most common bacterial food infection
�� sources . undercooked chicken/turkey/pork . unpasteurized milk . raw clams �� 1-10 days (3-5 avg.) for onset of symptoms �� up to 10% may develop serious, longterm complications |
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E. coli 0157:H7:
Normal flora of ... Found in (3). Effective dose is (low, really low, high, really high)? Produces ___ toxin. Onset of symptoms is ... ~# cases / deaths/yr |
normal flora of healthy cattle
�� sources . undercooked beef . unpasteurized fruit juice . sprouts �� LOW infective dose, produces verotoxin (shiga-like toxin) �� 1-10 days to onset of symptoms �� 60,000 cases with 50 deaths/yr |
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E. coli 0157:H7:
Known as ... Causes ... It is treated by ... complicatons (2) ... |
Disease
. Hamburger disease: bloody diarrhea (hemorrhagic colitis) . Self-limiting; 8 days average . Complications . Hemolytic-uremic syndrome, a blood and kidney disease in children . Thrombotic thrombocytic purpura, a dire disease in the elderly |
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E. coli 0157:H7:
Dx Tx ... |
�� Diagnosis - E. coli 0157:H7
. Culture stool samples . Testing for the toxin produced by the bacteria. �� Treatment . Fluid replacement . Physician, hospital care�ұ�]� |
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Listeriosis, caused by ...
about ... commonly found in what foods ... Onset ... Cases/yr ... ~mortality and rate ... |
Listeria monocytogenes
Gram-positive, motile . flagella . psychrophile . Food sources . soft cheeses . cold cuts Listeriosis . hot dogs . milk . raw meats and fish . 4 days - weeks to onset of symptoms . 2,500 cases/yr . 500 deaths (20% death rate)ase |
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Listeriosis,
signs/symptoms ... Infective dose ... pathopsysiology ... Very dangerous for which group ... |
Signs and symptoms
. Influenza-like symptoms . Fever . GI symptoms . nausea, vomiting, diarrhea . Infective dose - < 1000 cells . Invades GI epithelium . Enters host monocytes, macrophages, leukocytes . Septicemia (50% mortality) . Meningitis (70% mort.), encephalitis . Pregnant women/fetus (80% mort.) at risk |
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Listeriosis,
Dx ... Detection (in food) ... Tx ... |
Diagnosis
. Culturing L. monocytogenes from blood, cerobrospinal fuid, placenta . Food analysis . Culture . 5-7 days . No DNA detection methods yet . Treatment . Antibiotics . e.g., penicillin, ampicillin\ |
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Shigellosis:
Caused by (4) ... About ... Pathogenisis/epidemiology Dx, Tx, prevention ... |
�� Pathogen and virulence factors
. Caused by Shigella dysenteriae, S. flexneri, S. boydii, and S. sonnei . Gram negative bacteria . Virulence factors include enterotoxins such as shiga toxin �� Pathogenesis and epidemiology Shigellosis . Pathogen colonizes cells of the small, then large intestine . Incubation 1-3 days . Dysentery or watery diarrhea, fever, nausea �� Diagnosis, treatment, and prevention . Diagnosis based on symptoms and presence of Shigella in stool . Supportive treatment and administration of antimicrobials |
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Shigellosis:
Pathophysiology ... |
Sigella attaches to epitheilal cell of colon. Triggers endocytosis (goes into cell). Sigella multiplies in cytosol. Invades neighborinig epitheial cells, thus avoiding immune defenses. Forms mucosial absesses, and kills cells. Shigella enters blood stream, and is quickly phagocytised and destroyed.
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Salmonellosis:
Causative agent ... Commonly found in which foods (5) ... Onset ... Small fraction of those infected may develop ... |
�� Salmonella spp.
�� Gram negative bacterium �� sources . poultry . meat . eggs . sprouts . un-cracked eggs shells (1 in 10,000 contaminated) �� 12-24 hrs for onset of symptoms (18 hrs avg.) �� some remain carriers for months �� small percentage may develop serious chronic disorders.) at risk |
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Salmonellosis:
Pathopysiology ... |
Salmonella attaches to epitheial cells lining the sm. intestine.
Triggers endocytosis. Salmonella multiplies inside vesicles. Kills host cells, indusing cramps, fever and diarrhea. Bacteriemia if Salmonella moves to blood stream (typhi). Phagocytised, but not destroyed. Goes to blood centers (next question). Shed in feces. |
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Salmonella can affect these body parts:
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Liver
spleen bone marrow gallbladder (basically anywhere blood can go in large quantities, with the exception of the gall bladder ... you just have to remember that). |
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Typhoid fever:
causitive agent Symptoms ... Treatment ... Occurance ... Dx.... |
Infectious agent - Salmonella typhi
�� Symptoms - diarrhea, systemic disease, and a rash �� Treatment (2-4 weeks) . Fluids and electrolytes intravenously . antibiotics �� Occurrence - common in developing countries, but fewer than 400 cases in the U.S. each year �� Diagnosis . Blood culture . Stool culture . ELISA urine test |
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E. coli Description
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�� Gram-negative bacillus (1.1-1.5 �gm x 2-6
�gm) �� Motile, non-endospore former, facultative �� Growth range of 15-45�XC �� Optimal growth at 37�XC �� generation time = doubling time = 20 min �� best temperature for production of toxins |
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E. coli: Commonly resides in ...
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Enteric bacterium
�� Normal flora inhabitant of the intestine of humans, mammals, and birds �� No normal presence in environment �� Excreted in the feces (106-107/g) �� ~200 known pathogenic E. coli �� cause life-threatening diarrheal and urinary tract disease |
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E coli: Antigens (5)
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Traditionally characterized by their surface
antigens �� O = long polysaccharide chains of the LPS �� H = flagellar proteins (if motile) �� These antigens resulted in classification of serotypes �� numerous different O antigens (numbered 1-181; some now excluded, some identical) �� H may or may not be present (must have flagella; numbered 1-56; really only 53) �� Also K (heat sensitivity) and F (fimbrial)antigens |
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Six major categories of E. coli strains cause
enteric disease |
�� Enterohemorrhagic
�� Enterotoxigenic �� Enteroinvasive �� Enteropathogenic �� Enteroaggregative �� Diffuse-adherence �� All share adherence as a virulence mechanism |
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Enterohemorrhagic strains (3)
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�� Shiga toxin-producing E. coli (STEC)
�� E. coli 0157:H7 most common STEC serotype in North America �� Verotoxin producing E. coli (VTEC) �� Enterohemorrhagic E. coli (EHEC) |
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Enterohemorrhagic E. coli (EHEC)
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�� Only pathogenic E. coli that has a
definite zoonotic origin �� Reservoir �V cattle, other ruminants �� Occurrence �V North America, Europe, Japan, South America, South Africa �� Transmission �V food contaminated with ruminant feces �� Most common cause of kidney failure in children |
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Enterohemorrhagic E. coli (EHEC) Pathophysiology
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Following ingestion organism grows in
the small intestine �� Produces Shiga toxin - a potent cytotoxin that inhibits protein synthesis within eukaryotic cells �� Causes bloody diarrhea and kidney failure |
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STEC
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Now recognized that over 200 serotypes
associated with Shiga toxin (6 important serogroups, e.g. 0157) �� Shiga toxin Stx 1 and Stx 2 are also called �� Verocytotoxin �� Verotoxin �� Shiga-like toxins �� Predominant serotype O157:H7 �� Bloody diarrhea in all age groups �� Young children - may lead to hemolytic-uremic syndrome (HUS), kidney disease �� O157:H7 causes 90% of HUS in N.A., 50% in Germanyria |
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STEC:
Infectious dose ... % resistant to antibiotics ... fatality percent ... |
Infectious dose <100 cells, but
people can carry the organism as transient gut flora w/o disease. �� ~ 20% of O157 isolates resistant to antibiotics �� 5-10% of cases have fatal complications |
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STEC: Toxin pathophysiology
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Toxin production is a prerequisite to
disease �� Toxin passes through intestinal epithelium to reach the endothelial cells lining the small blood vessels that supply the �� Gut �� Kidney �� Other viscera |
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STEC: Survival outside of host ...
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Survival
�� Well adapted to survival in animal feces �� Several weeks to months �� Temperature and water activity dependent �� Lab study - spiked feces survival >70 days at 5�XC, 0.98 aw �� Surface of grazing land - decrease from 108 CFU/g to 105 CFU/g within 50 days, but still detectable for up to 99 days} |
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STEC Transmission via food
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Transmission via foods
�� Main - bovine origin �� beef (mass produced ground Milkborne outbreaks �� 1994 - UK milk sold as pasteurized �� 100 affected �� ~1/3 hospitalized; 9 with HUS �� 1999 largest milkborne outbreak in the UK �� 144 cases; 32% admitted to hospital with HUSscerabeef)Transmission via foods �� Others �V foods fertilized with manure �� Fruits �� Unpasteurized fruit juice �X Apple cider �� Potatoes �� Fresh vegetables eaten raw �� sprouts, lettuce, tomatoes �� raw milk (but only <1% - 3% of samples positive) �� Recent outbreaks �� Low pH foods �� Fermented salami �� Mayonnaise �� Yogurte |
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STEC: Direct person to person ... senerio.
Rate of disease, US ... |
Direct person-to-person (day care
facilities) �� Long term shedding in 13% of patients despite clinical care �� CDC - STEC cause approximately 100,000 illnesses, 3,000 hospitalizations, and 90 deaths annually in the U.S. |
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STEC Control Strategies
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Improved cattle herd management to limit prevalence of
carriers �� Minimize slaughterhouse contamination of meat by animal feces �� Decrease fecal contamination of foods consumed raw; fertilizing with animal waste �� Pasteurize dairy products �� Wash fruits and vegetables, peel �� Wash hands �� Cook beef adequately (70oC) �� Ensure hygiene in childcare centers� |
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Enterotoxigenic E. coli (ETEC): causes diseases in ...
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�� 75% of traveler��s diarrhea cases
�� Infants and children in developing countries �� 380,000 deaths annually in children < 5 yrs. �� Adhere to mucosa of small intestine, but do not invade �� One heat-labile and two heat-stable enterotoxins �� To cause disease must colonize and produce toxins� |
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Enterotoxigenic E. coli (ETEC) Transmission
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�contaminated food and
water �� Lettuce in salads �� Fresh vegetables �� Water �� Soft cheeses (brie and camembert): >3000 cases in U.S. in 1983 �� Infection rate in Mexico for visitors = 50% �� Not a problem for residents in Mexico �� Chronic exposure resulting in production of secretory antibodies present in the bowel �� May prevent successful colonization of the pathogen |
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Enteroinvasive E. coli (EIEC);
Affects ... Signs ... Where in world found ... Reservoir ... Transmission ... |
�� Invasive disease in the colon �V all age
groups �� Water and bloody diarrhea �� Developing countries �� Reservoir �V humans �� Transmission �V contaminated food �� In 1997, 387 cases in U.S. due to imported soft cheeses (brie, camembert, coulommiers)ithin 50 |
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Enteropathogenic E. coli (EPEC) ... describe.
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�� Oldest recognized category
�� Most frequent cause of diarrhea in infants in developing countries; most cases in first 3 years of life �� No invasive disease �� No toxin production �� Transmission �V contaminated formula and weaning foods |
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Enteroaggretive E. coli (EAEC): Describe ...
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�� Diarrhea-causing pathogen, or only
some strains? �� Developing countries �� Adhere to enterocytes, form thick film of aggregating cells and mucus �� 10-20% of traveler��s diarrhea |
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Hepatitis A virus
Food sources ... Onset of symptoms ... Infection persists for ... |
Food sources (also transmitted
person-to-person) �� raw clams or oysters �� seen in glazed doughnuts, orange juice, salads �� onset of symptoms �� 10-50 days following ingestion �� most contagious 10-14 days BEFORE symptoms �� infection persists for weeks-months �� some may lead to liver damage?� |
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Hepatitis A virus
Symptoms ... Rates U.S. ... |
Symptoms
�� Fever �� Nausea, vomiting �� Abdominal, joint pain �� Dark urine �� Jaundice �� Decreasing in the U.S. �� 25,000 cases in 2007 �� Vaccine introduced in 1995 �� Children, travelers, at risk population/ |
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Norovirus
about ... |
Single-stranded RNA, non-enveloped
virus �� Caliciviridae family �� Norovirus official genus name (previously described as ��Norwalk-like viruses��) �� Five groups, three affect humans �� Up to 30% of infections asymptomatic (CDC, 2010)m� |
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Norovirus:
Causes ... % of gastroentitis ... Environmetal exposure ... |
More cases of acute gastroenteritis than
any other foodborne pathogen (~21 million/yr) �� Nearly 60% percent of estimated illnesses, but a much smaller proportion of severe illness, caused by norovirus �� Highly contagious �� Environmental persistence �� Difficult to control with routine sanitation�?� |
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Norovirus:Illness
Incubation ... lasts ... Characterized by s/s ... Treatment ... Increased risk of complications to which groups? Why? |
�� Incubation period is 12-48 hours
�� Illness lasts 12-60 hours �� Self-limiting �� Increased risk for complications because of volume depletion and electrolyte disturbances �� Elderly �� Children �� Severe underlying medical conditions �� Hospitalization of adults who are otherwise healthy is rare �� Neither specific antiviral treatment nor a vaccine has been developed for noroviruses �� Characterized by sudden onset of �� Nausea �� Vomiting �� Watery diarrhea( �( |
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Norovirus:
Where outbreaks occur (4) with percentages ... |
Of 660 outbreaks confirmed by CDC
between 1994 and 2006, �� 36% were from long-term care facilities (e.g., nursing homes), �� 31% were from restaurants, parties, and events, �� 20% were from vacation settings (including cruise ships), and �� 13% were from schools and community settings |
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CDC Vessel Sanitation Program ... Mission:
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�� Established early 1970s
�� Mission: �� inspecting cruise ships (periodic and unannounced) �� monitoring gastrointestinal illnesses and investigating or responding to outbreaks on cruise ships .13 passengers with foreign itineraries sailing into U.S. ports �� training cruise ship employees on public health practices. providing health education and reliable and current public health information to the cruise ship industry, the traveling public, public health professionals, state and local health authorities, and the media |
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Mad Cow Disease
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Bovine spongiform encephalopathy (BSE)
�� 1986 �V new animal illness in U.K. �� slow-progressing neurological infection, cattle stagger/collapse �� sponge-like h sponge holes in brains of animals �� 1989 �V USDA imposed ban on imports of live cattle, sheep, and derived products from the U.K. and countries with BSE outbreaks �� 1990 �V USDA surveillance to detect BSEaffected cows addition of rendered meat-and-bone meal to livestock feed as (cheap) dietary supplement �� scrapie-infected sheep carcasses in mix; cost-cuts to use lower cooking temp. �� low rendering temperatures failed to inactivate previously unrecognized infectious proteins (prions) �� 1997 �V bans on use of animal protein in cattle feed �� 2003 �V first case in U.S.ters� |
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Spongiform Encephalopathies
Types (2) ... Number of cases in 2004 ... |
Creutzfeldt-Jakob Disease (CJD) �V rare, fatal,
human disease �� 1996 �V U.K., link between CJD and people who ate BSE-contaminated meat �� Variant CJD (vCJD) acquired by diet �� 153 cases worldwide as of 2004 �� ��species jump�� of pathogenic prions �� Prions �V abnormally folded prion protein �� Definition �V infectious proteinaceous particle� |
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Spongiform Encephalopathies:
Incubation period ... Symptoms/signs ... |
Incubation period measured in years
� Illness lasts 13-14 months � When prions hit a critical level in the brain, symptoms progress very quickly � Neurologic abnormalities � Ataxia � unsteadiness due to disease in brain tissue � Dementia � loss of memory and confusion � Myoclonus � abnormal contraction of muscles later in the illness � Immobility � Muteness � Death |
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Food Microbiology
Difficulties ... Solutions. ... |
Difficulties
�� microbiological analyses are destructive �� 100% inspection is impossible �� consumer cannot be 100% protected �� length of many conventional analyses �� perishables released/consumed before completion of analysis Solutions �� end-product analyses performed as part of QA plan �� representative sampling allows acceptance or rejection of batch based on samples collected �� rapid methods provide results in a few hoursdia |
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Food Microbiology
Sampling and Investigation Methods |
�� collection of large/representative food
samples �� batches in packets, cans, bags, containers �V individual testing of a number of units selected at random �� package food products �� package opened only in the laboratory �� sampling performed aseptically �� sampling tools �V wrapped and sterilized |
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Food Microbiology
Sampling and Investigation Methods: Liquids ... |
Examples: milk, ice-cream mix, sugar
syrups �� Representative sample �� mixed thoroughly up and down (e.g., sterile ladle) �� 100-500 ml dispensed into sterile container �� transported to the laboratory (transport temp.) �� in the lab., mixed again before analysis |
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Food Microbiology
Sampling and Investigation Methods:Solid samples ... |
May be performed using sterile scalpels,
spoons or cork-borers �� Particulate food (e.g., flour, dried milk) should be mixed, and approx. 100 g collected �� Bulk products �� larger samples from more than one location should be collected �� mixed and analyzed separatelyomm |
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Food Microbiology
Sampling and Investigation Methods: Meat, fish, and similar foods |
�� collect deep and surface samples
�� careful collection of deep samples to minimize contamination from surface �� foodstuffs such as fresh and cooked meats �V sampled using sterile carving knife, scalpel, forceps �� frozen foods �V cork-borer or electric drill (bore-extracting bit) used to obtain deep samples without thawing �� surface slices �V thin slices of superficial layers, homogenize (with diluent), plate �� rinses and washes �V agitate in sterile diluent �� sausages, dried fruits, vegetables �� swabs �V use sterile template for quant. results �� adhesive tape �V pressed against food/equipment surface, pressed onto suitable culture medium �� contact plates�]� |
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Food Microbiology
Sampling and Investigation Methods: Transport and Storage |
�� frozen foods - kept frozen until
analysis �� perishable (unfrozen) foods �� refrigerate until tested �� refrigeration for �d3 days will result in microbial amplification, and may cause death of certain microorganisms �� record sampling, transport, and storage conditions |
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Facts about food storage:
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> 54 billion meals are served at 844,000
commercial food establishments in the US/yr 46% of the money Americans spend on food goes for restaurant meals On a typical day, 44% of adults in the United States eat at a restaurant A mean of 550 foodborne disease outbreaks per year reported to the CDC from 1993 through 1997 >40% were attributed to commercial food establishments |
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Top ten risiest foods: Food, #outbreaks, #cases of illness.
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Product # of outbreaks Reported cases of
illness LEAFY GREENS 363, 13,568 EGGS 352, 11,163 TUNA 268, 2,341 OYSTERS 132, 3,409 POTATOES 108, 3,659 CHEESE 83, 2,761 ICE CREAM 74, 2,594 TOMATOES 31, 3,292 SPROUTS 31, 2,022 BERRIES 25, 3,397 |
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