Food poisoning

Question 1

food borne infection

Answer 1

infection with an agent- that results in (diarrhoeal) disease
usually zoonotic
salmonella , E.coli and noravirus

Question 2

food poisoning

Answer 2

exposure to toxins that result in disease
contamination,poor storage or handling
staphylococcus toxin, bacillus entertoxin, alfalotxins from fungi

Question 3

when does food security exist

Answer 3

when all people at all times have physical, social and economic access to sufficient, safe and nutritious food which meets their dietry needs and food prefenerences for an active and healthy life

Question 4

why food security is a problem

Answer 4

need for sustainable agriculture to produce safe and nutritious food in face of climate change and conflict
improving productivity by reducing disease, improving welfare and maximising yeilds
incerased consumer demand and choice for animal protein
changes in livestock practice- rbas and peri-urban rearing of monogastric livestock
changing risks of food safety and zoonotic disease

Question 5

what is DALY

Answer 5

the disability adjusted life year

a measure of overall disease burden, expressed as the number of years lost due to ill health, disability and early death

Question 6

what are the most common food borne disease pathogens

Answer 6

campbylocbacter (500, 000)
clostridium perfringens (80, 000)- gastroenteritis, diarrhoea and vomitting
noravirus
salmonella enterica (40, 000)
E.coli- hamerrohagic disease and renal failure
listeria
heo E

Question 7

types of campbylobacter

Answer 7

jejuni and coli
gram -ve spiral rods
microaerophilic and slightly thermophilic

Question 8

campbylobacteriosis

Answer 8

2-5 days after infection
diarrhoea (blood), abdominal pain, fever, vomitting 6 days
long term sequelae (neurological rpblems such as guillain - barre syndrome
developing countries- infection- watery diarrhoea, like cholera

Question 9

main risk groups for campbylobacter

Answer 9

under 5s, over 65s
bowel cancer
proton pump inhibitor drugs (increased gatric pH)

Question 10

sources of campbylobacter

Answer 10

poultry meat (60-70%)
red meat
water

Question 11

why is broiler chicken so associated with campbylobacter

Answer 11

core temp 41-42 suits thermophilic bugs
low O2 tension in gut- suits microaerophiles
high levels of growth supported in caeca
high levels of shedding in faecal and caecal droppings- and coprophagic behaviour- rapid spread
persists in caeca and birds can be infected with a succession of different strains
caeca primary site of C.jejuni colonisation

Question 12

sampling and microbiology of campbylobacter

Answer 12

15 samples/session
3 pooled neck samples
diluted 1:9 in buffered pepide water
processed
quantification on mCCDA
confirmation on second media

Question 13

FSA targets fro campbylobacter

Answer 13

reduce contamination of carcasses more than 1000 cfu
secondary target- reduce lower level contamination
no targets for liver of deep muscle
2017 - sig reduction
don’t take into account biology of C
based on unproven model

Question 14

E.coli pathogens associated with enteric infection

Answer 14

EPEC - entero pathogenic ecoli (child diarrhoea)
ETEC- entero toxingenic (travellers diarrhoea)
EIEC- entero invasive
EHEC- entero haemorrhagic (STEC/VTEC)
EAEC- entero aggregative (persistent diarrhoea)

Question 15

EHEC - vet public heath sig.

Answer 15

most EHEC/STEC colonise GI tract of ruminants withou disease
5% cattle UK faecal shedding
some strains- diarrhoea in calves andpigs
distal rectum
bacteria from GI tract could contaminate meat at slaughter
human cases- poorly cooked ground/minced beef (hamburger disease)- or cross contamination of cooked and raw meat

Question 16

yersinia and shigella

Answer 16

both enterobacteriacae- similar to salmonella and ecoli
yersinia enterolitica causes food born yersiniosis
4 spp. shigella- human dysentery
shigella- food borne or person- person
shiga toxins produced by same species

Question 17

listeria monocytogenes

Answer 17

gram +ve
rod shaped intramacrophage pathogen
cooked meats, pate, soft cheese, smoke fish, pre-prpared sandwiches and cook chill meals
grow well at low temperatures- particular risk

Question 18

human listeriosis

Answer 18

most cases mild (gastroenteritis of flu)
pregnant women, elderly and immunocompromised are risk
septacaemia and CNS infection- increaising
60+ systemic infection problem
non-preganncy associated infection- mortality rate in excess of 30%

Question 19

bacterial toxins

Answer 19

exotoxins produced by a range of bacetria cause food poisoning
enterotoxins usually induce diarrhoea, emetic toxins vomitting
staphylococcus aureus produced 5 different enterotoxins
sporadic outbreak of staph. aureus food poisoning- usually poor hadnling
other toxins associated with milk products

Question 20

bacillus food poisoning

Answer 20

bacillus cereus gram +ve spore froming rod
2 toxins which are heat stable
associated with pulses and rice

Question 21

bacillus pathogenesis

Answer 21

vegetative cells killed by cookiing, spores are not
if cooked rice/pulses are not chilled, spores can germinate, bacteria grows and toxins produced
toxins not destoryed by reheating
consumption- fried rice exposure of toxins
emetic toxin induces rapid and profuse vomitting (15 mins after consumption)
enteric toxin induces profuse, painful but short lived diarrhoea (4-6 hrs after consumption)

Question 22

clostridium poisoning

Answer 22

gram +ve
spore forming rods
pefringens and botulinun- sever food poisong
difficile (part of gut flora)- diarrhoea following ntimicrobial chemotherapy - disruption of nromal flora
difficile- frequently resistent and major nosocomial problem

Question 23

C. botulinum

Answer 23

spores in varierty of environments
poorly canned, bottled foods or in honey
germinating spores- lead to formation of vegetative cells that release a potent toxin
toxin- blocks nerve synapsis causing paralysis and death
1970s- tinned salmon and corned beef

Question 24

C. perfringens

Answer 24

type A toxin- survive in animal GI and soil
spores contaminate meat, may survive cooking
poorly stored turkey- poorly stored cooked meat and re-heated- allows germination and massive numbers of vegatative cells
ingestion leads to enterotoxin production in large intestine- diarrhoea
B toxin (rarer)- producing type C strains- acute necrotising GI disease following consumption of poorly cooked pork (papua new guinea)

Question 25

Vibrio parahaemolyticus

Answer 25

gram -ve
comma shaped rods
halophile (salt)
associated with fish and shelffish
uncooked shellfish
invades gut epithelil cells and produces hameolytic cytotoxin leading to diarrhoea

Question 26

viral enteric infections

Answer 26

viral- most common cause of gastroenteritis in humans
roat, calici, astro, corona, adeno
short lived and uncomfortable
rotavirus- infant mortality
faecal oral route- poor hygiene, food or water contamination (seage contamination of seafood)

Question 27

noravirus

Answer 27

ssRNA calicivirus- highly infectious
winter vomitting bug
largest cause of diarrhoeal disease in UK
shcool, hosptials, cruise ships
fever, headaches and abdominal pain and dirahoea and vomittig
person- person, 70, 00 foobrrone

Question 28

hepatitis A

Answer 28

ssRNA picornavirus- excreted in high amounts in faeces of infected humans
rare in UK
faecal contamination of food and water
passive Ig or active vaccination
sewage workes high risk

Question 29

foodborne Hep A

Answer 29

main source= contaminated shellfish (oysters)
repliactes in GI tract- migrates to liver causing cell damage
nausea, D and V, jaundice, flu

Question 30

Hep E

Answer 30

short lived, self limiting hepatitis but can lead to severe disease and death
rise
6% of pigs infected and 93% seropositive
pork and pork products

Question 31

how do bugs survive on food so well?

Answer 31

attaching to surface of foods or preparation areas, replicating and forming communities of bacteria= biofilms
biofilms= much tougher than individual bugs to drying, washing or disinfecting
EAEC particulalry good at forming biofilms on food or in gut, making them persistent and capable of causing persistent enteritis
listeria- resistent to cold and grow well
salmonella- have resilient froms that persist well even in chilled foods

Question 32

how vegetables and other food can be a source of foodborne infection

Answer 32

manure fertislier
continuous warm water system bena sporuts salmonella and ecoli
roden and wild bird- procesing (cadburys)
livestock carriers- faceal contamination of farmland, water and environment