Term
|
Definition
| metabolically dormant, highly resistant to many processing measures, capably of germinating into vegetative/active microbe. |
|
|
Term
|
Definition
1. Elevated resistance/survival as compared to vegetative cells
2. Secreted by cells following cell lysis/multi-stage process.
3. Only secretes toxins if it GERMINATES. |
|
|
Term
| AEROBIC OR FACULTATIVELY ANAEROBIC SPOREFORMER: genus Bacillus |
|
Definition
1. genus Bacillus
2. B. Cereus
3. B. subtilis
4. B. anthracis |
|
|
Term
|
Definition
1. FOODBORNE PATHOGEN (intoxication)
2. most common among Bacillus foodborne disease |
|
|
Term
|
Definition
| enterotoxin-producing species associated mainly with milk. (not common) |
|
|
Term
| genus Bacillus TOXINS PRODUCED: |
|
Definition
1. entertoxin, emetic toxin.
2. chemically similar to CLOSTRIDIUM PERFRINGENS TOXINS
3. HEMOLYSIN BL (HBL): primary diarrheal toxin |
|
|
Term
| genus Bacillus toxins: ENTEROTOXIN |
|
Definition
Diarrheal disease
(a) short duration w/o fever
(b) foodborne transmission
(c) some vomiting, diarrhea, cramping |
|
|
Term
| genus Bacillus toxins: EMETIC |
|
Definition
VOMITING
(a) more severe symptoms
(b) 1-6 hr incubation period post ingestion
(c) similar to STAPHYLOCOCCAL GI INTOXICATION
(d) CHINESE RICE SYNDROME: loss of hot holding capacity in foods on buffets (dense source of starch)
i) organism contaminate post-cooking; if temp drops during holding, than toxin synthesized
ii)food intoxication |
|
|
Term
| NON-PATHOGENIC BACILLUS SPECIES |
|
Definition
|
|
Term
non-pathogenic Bacillus species:
MESOPHILIC AND THERMOPHILIC |
|
Definition
SPOILAGE OF LOW-ACID CANNED FOODS
1) canned veggies and meats
2) spore survives processing, germinates, and grows.
(a) acid fermented from sugars
(b) little or no gas production FLAT SOUR!! (very characterisic of this genus!) |
|
|
Term
non-pathogenic Bacillus species:
MESOPHILIC SPECIES |
|
Definition
| B. polymyxa, B. macerans, B. subtilis |
|
|
Term
non-pathogenic Bacillus species:
THERMOPHILIC SPECIES |
|
Definition
| Geobacillus stearothermophilus |
|
|
Term
|
Definition
RANGE: -15-40 degrees C
OPTIMUM: 10-15 degrees C |
|
|
Term
|
Definition
RANGE: <7-40 degrees C
OPTIMUM: 20-30 degrees C |
|
|
Term
|
Definition
RANGE: 20-45 degrees C
OPTIMUM: 25-40 degrees C |
|
|
Term
|
Definition
RANGE: >45-90 degrees C
OPTIMUM: 55-65 degrees C |
|
|
Term
| OBLIGATELY ANAEROBIC SPOREFORMER: |
|
Definition
genus Clostridium
C. botulinum, C. perfringens
both are foodborne pathogens |
|
|
Term
|
Definition
1. Causative agent, foodborne botulism
2. FOODBORNE INTOXICATION!!!
3. Strains are classifed based on toxin synthesis
4. BOTULINUM TOXIN = MOST POTENT KNOWN TO HUMANS!
5. not effective competitor in various foods/toxin production = most problematic in heated foods where microbes are killed |
|
|
Term
| C. botulinum: Microbe growth |
|
Definition
ANAEROBE
1) fastidious w/ respect to nutrients ( must be provided by environment/food for growth, toxin production
2) temps: 10-50 degrees C = OPTIMAL
(NO GROWTH AT REFRIGERATION)
3) No growth at pH <4.5 (low acid canned foods = most problematic) threshold = <4.6 for low-acid canned foods
4) min water activity for growth = .94 |
|
|
Term
|
Definition
INTOXICATION
1) absorbed through intestinal walls
2) NEUROTOXIN: induces FLACCID PARALYSIS which inhibits acetylcholine release shutting down muscle's ability to contract.
(a) descending paralysis of smooth muscles: diaphragm (suffocation, cannot inhale/exhale)
(b)toxin is heat sensitive (80 degrees C, 10 min; boiling H20) |
|
|
Term
Foodborne Botulism:
SYMTPOMS |
|
Definition
(a) droopiness of eyelids
(b) chronic fatigue
(c) GI symptoms (body trying to get rid of toxin
(d) fatal if not treated (3-5 days)
(e) onset = 12-72hr post ingestion |
|
|
Term
|
Definition
(toxico-infection)
results when cells colonize infant intestine and secrete toxin
(1) more commone than foodborne botulism, but still rather uncommon
(2) Unpasteurized honey/maple syrup: transmission foods |
|
|
Term
|
Definition
Foodborne perfringenosis
(toxico-infection)
1. organism is encapsulated, non-motile, toxin-secreting (types ABCD&E) |
|
|
Term
|
Definition
| secrets polysaccharides to form a protective barrier |
|
|
Term
C. perfringens:
growth and phsiological characteristics |
|
Definition
1) Mesophile (37-45 degrees C)
2) pH: 5.0-8.7 (min-max); optimum 5.5-8.0
3) water activity: 0.95-0.97 required for growth; spore formation requires higher (0.98-0.99) (doesn't do well in reduced moisture environments)
4) variable heat risitance amongst strains; spores can be inactivated with extended freezing |
|
|
Term
C. perfringens:
toxin and disease syndrome |
|
Definition
1) toxin produced and released into body during spore production and release toxico-infection (YOU MUST EAT THE LIVING CELL!)
(a) toxin binds to host epithelial cells and causes changes in cell permiability, leading to cell death.
(b) when the cell lysis & releases the spore, the toxin is released. |
|
|
Term
|
Definition
(a)explosive diarrhea
(b)Nausea and fever not common
(c)abdominal pain
(d)onset: 6-12 hrs post consumption
(e) not typically lethal |
|
|
Term
C. perfringens:
Epidemiology |
|
Definition
Foods of concern:
(a) raw meats, poultry (esp with gravies and sauces)
(b)dehydrated soups, sauces
(c)raw veggies
(d)spices
(e)Meat dishes: heat processing does not kill spores; incomplete REHEATING in home allows GERMINATION AND TOXIN SYNTHESIS |
|
|
Term
C. perfringens:
Control/Prevention |
|
Definition
(a)complete cooking
(b)washing, sanitation
(c)refrigeration & complete re-heating |
|
|
Term
Other Clostridia: spoilage
Proteolytic and non-proteolytic strains |
|
Definition
(1)spoilage: odors gas
(2)breakdown of food components |
|
|
Term
Other Clostridia: spoilage
Mesophilic and Thermophilic types |
|
Definition
(1)heat process resistance
(2)post-processing cooling and temperature abuse |
|
|
Term
| Other regular sporeforming rods |
|
Definition
Desulfotomaculum nigrificans
Alicyclobacillus acidoterrestris
Thermoanaerobacterium
1. spoilage thermophiles
2. foods: canned low acid, juices, acid foods |
|
|
Term
| Regular non-sporeforming rods |
|
Definition
| Genus: Listeria, Lactobacillus |
|
|
Term
|
Definition
| Facultative anaerocib motile coccobacilli (short, flat rods) |
|
|
Term
Listeria: Human Pathogen
L. monocytogenes |
|
Definition
| foodborne intracellular parasite |
|
|
Term
Listeria:
Biochemical and physiological characteristics |
|
Definition
a) catalase, cytochrome positive
b) glucose fermented to L-lactic acid
c) peritrichous flagella (synt opt at 20-25C)
d) tumbling motility (handspring motion under phase contrast
e)Hemolysis: Synthesis of B-hemolysin LISTERIOLYSIN O (LLO)
3)optimal production at 37C
4)active at pH 5.5 but not 7.0
5)carries out B-hemolysin on blood agar (colonies are small and have small cleared zones: evidence of growth)
f)PSYCHROTROPHIC: growth at 7C slow but sustained: problem for refrigerated post-process contaminated foods, pasteurization sensitive |
|
|
Term
|
Definition
1)degrades erythrocytes and phagocytes
2)synthesized by L. monocytogenes |
|
|
Term
|
Definition
| only targets vacuole, allowing lysteria to be more efficient and go undetected by immune system |
|
|
Term
| Listeriosis: foodborne infection |
|
Definition
1)first IDed in humans: 1929
2)colonizes intracellularly (GI gut cells) escape host immune response
a)can reach placenta: spontaneous abortion/stillbirth
b)specialized proteines alow invasion and cell-to-cell movement: LLO, INTERNALINS, ACTIN TAIL FORMATION aids in cell movement/crossing into new cells in host.
3)immunocompromised at highest risk: elderly, neonates, cancer/AIDS patients.
4)infectious dose not known/pinpointed |
|
|
Term
Listeriosis: foodborne infection
SYMPTOMS |
|
Definition
1)Fever (indicating infection)
2)Nausea
3)Meningitis (adult and fetuses: infection @ delivery)
4)Sepsis |
|
|
Term
Genus Listeria:
EPIDEMIOLOGY AND FOODS OF CONCERN |
|
Definition
1)incidence: .02% disease/28-20% fatal
2)environmentall UBIQUITOUS
3)domesticated animals |
|
|
