Lecture 9 Flashcards
Bacillus Cereus
- Gram ____, facultative _____, ______- forming rod
- gram +, faculative anaerobe, endospore-forming rod
Bacillus cereus two forms:
- emetic (vomiting)/ 7 serotypes
- diarrheal/ 7 serotypes
Bacillus cereus is ______ in the environment where it _____, _____, and _______
ubiquitous, germinates, grows, sporulates
Bacillus cereus illness occurs due to ______ and _______ of spores in contaminated food and subsequent production of toxins
survival and multiplication
Bacillus cereus tolerates ____% salt concentrations
7.5%
Bacillus cereus has an estimated ______ cases/yr in Canada
37,000
Is bacillus cereus a notifiable and a reportable disease?
Not a notifiable nor a reportable disease
B. cereus is primarily linked to foods that have been ____________
cooked and cooled too slowly
B. cereus is a FBI caused by ______________
ingesting large numbers of bacterial cells and/or spores in contaminated food (diarrheal) or food contaminated with pre-formed toxin (emetic)
B. cereus: ______ and ______ destroyed by heat
- vegetative cells (56C for 5 minutes)
- spores (126C for 90 minutes)
B. cereus: sanitizers ______ vegetative cells, spores are _______
destroy, highly resistant
B. cereus caused by _________ to cooked foods
cross contamination
B.cereus diarrheal syndrome toxin?
enterotoxin produced in intestine
B. cereus emetic syndrome: emetic toxins
- pre-formed in food
- stable from pH of 2-11
- heat stable at 126C for 90 minutes
- temperature abuse= cells grow and produce emetic toxin
- reheating will not help
B. cereus diarrheal syndrome symptoms:
- mimics ___?
- cramps
- watery diarrhea
- nausea
- very little vomiting
- fever uncommon
- mimics C. perfringens
- Incubation period: 6-15 hours
B. cereus emetic syndrome symptoms:
- nausea
- vomiting
- diarrhea (<30%)
- fever uncommon
- Incubation period: 0.5 hours, can be 15-30 minutes
B. cereus foods related to diarrheal syndrome?
- meat and vegetable soups often implicated
- other food vehicles: milk, fish, mashed potatoes, pudding, cereal dishes with corn
B. cereus foods related to emetic syndrome?
- cooked rice (frequent); been called fried rice syndrome
- other food vehicles: pasteurized cream, spaghetti, mashed potatoes, vegetable sprouts, reconstituted infant formula
What is the correct way to prepare rice? (3 steps)
- rice should be boiled in small quantities during the day
- after boiling, rice should be kept hot or cooled rapidly
- under no circumstances should cooked rice be stored at room temperature for longer than 2 hours
Bacillus cereus:
- infectious dose
- type of illness
- route of transmission
- incubation period
- duration of illness
- mortality
- diagnosis
- treatment
- 10^6 organisms/g (range 10^5 to 10^8)
- toxin/enterotoxin
- ingestion of contaminated food (often starchy foods)
- diarrheal type: 6-15 hours; emetic type: 0.5-6 hours
- lasts 24 hours (typically self limiting
- low mortality rate
- diagnoses with faeces or vomitus
- self limiting illness; supportive treatment for dehydration
B. cereus growth factor:
- pH
- temperature growth range
- oxygen
- water activity
- biofilm formation
- foods associated with illness
- other sources
- 4.9 to 9.3
- 4C to 48C *small % of strains are psychotropic; typically 10C to 48C (optimum is 28C to 35C)
- facultative anaerobe
- 0.91-0.95
- yes; biofilms also produce spores
- rice, pasta, often starchy foods
- widespread in the environment and often isolated from soil and vegetation
Staphylococcus aureus:
- gram ____, ____-forming
- ____ species and subspecies in the genus Staphylococcus
- Staphylococci are _____ and _____ to eradicate
- causes ______, _____, _____, _____, and ______
- highly tolerant to _____ and ______ (can grow in these foods)
- Gram positive, non-spore forming
- 32
- ubiquitous; impossible
- staphylococcus food poisoning, toxic shock syndrome, pneumonia, post-operative wound infection, and nosocomial bacteria
- salt and sugar
MRSA stands for:
Methicillin-resistant staph. aureus (can be foodborne)
Is S. aureus a common food poisoning?
Yes
S. aureus illness from ingestion of ________
enterotoxin pre-formed in food (9 types- A-J); heat stable
S. aureus symptoms are generally _____ and recovery is ______= illness ______ reported
mild symptoms and rapid recovery; rarely reported
Primary reservoir for S. aureus is ______
humans
Incubation period for S. aureus is _________
- short (but not as short as B.cereus)
- 1-6 hours, typically 2-3 hours
S. aureus has an estimated of ______ cases per year in Canada
25,000 cases
Is S. aureus a notifiable and reportable disease?
It is not a notifiable disease nor a reportable disease
S. aureus symptoms:
- vomiting
- abdominal cramping
- diarrhea
- nausea
- severe cases: dehydration, headache, muscle cramping, changes in blood pressure and pulse
Foods related to S. aureus?
- foods with improper food handling and temperature abuse
- outbreaks associated with:
- pork
- bakery products
- beef
- turkey
- chicken
- eggs
- soft cheeses
- RTE foods
Staphylococci can exist in any and all foods that are ______ or ______
handled directly by humans or are of animal origin