Foodborne Dz And Outbreak Investigation Flashcards
Origins of food borne hazards
> e.coli
- present in water, cattle act as reservoir (manure infects)
campylobacter
- in environment introduced in broilers houses
listeria
- envirment contamination (steel pipes drains etc.)
Give egs. Foodborne illness caused by biological, chemical and physical hazards
> Biological
- animal, human or envirment origins
Chemical and physical eg. Dioxins and mycotoxins transmissable by food of animal origin
Which food borne dz has highest mortality rates?
Listeria (proportionally)
> but the public health impact is a function of the fatality rate and the incidence of infection
Which is the highest number of cases impact pathogens of foodborne dz (UK)
- campylobacter over half
- norovirus
Outline FSA priority list of foodborne diseae from the 2010-2015 action plan
> campylobacter > listeria > e. Coli > salmonella > norovirus > clostridium perfringens
Which food group has the highest risk of food borne disease per serving
Poultry (compared to cooked vegetables)
- eggs
- red meat
- sea food
- milk
- other dairy lowest risk
Sources of campylobacter
- endemic in animals (poultry, cattle, sheep, pigs)
- sources food and nonfood eg. Untreated water
Clinical signs campylobacter
- incubation period 2-5d
- d+ and abdo pain
- self limiting in 10d
- rare sequalae : Guillan Barre syndrome
How does seasonal incidence of campylobacter change ?
- seasonal peak late spring and summer (maybe d/t flies? Not known)
- mirrored by humans (sometimes this proceeds the poultry rise!!)
Aim of FSA 2010-2015 wrt campy?
Decrease numbers of highly contaminated chickens from 27% to 10%
> hasn’t happened!!!
How can campylobacter tried be managed?
- NB even doing these things risk of campy infection is VERY HIGH*
> on farm - biosecurity fly screen, feed and water additive, vax, genetic resistance
> farm level management or husbandry - thinning or partial depopulation strong risk factor for flock colonisation
> slaughter and processing - campy+ flocks cross contaminate at abbattoir , slaughter last
> freezing/hot water/chemical decontamination
> consumer - cook properly, avoid cross contamination
Second most common cause of food borne dz in UK?
Salmonella
- and most common pathogen causing food borne OUTBREAKS across the WHOLE EU
- cf. campy which causes sproadic cases NOT outbreaks
Trend of salmonella case
Decreasing but still high (s. Enteridis poultry)
Clinical signs salmonella
- incubation period 12-48hrs
- VD+ abdo pain and fever
- self limiting 3-5d
Which sero are of salmonella exist?
- s. Dublin cattle
- s. Diarizonae sheep
- s. Typhimurium pigs
> s. Enteridis POULTRY most successful cause of decrease in salmonella cases
Where is salmonella a hazard?
- raw egg (mayonnaise, ice cream)
- eggs contaminated before shell is formed
- pasteurisation destroys
Hazards milk and milk produce
- TB
- Brucella
- Salmonella
- Campylobacter
- Listeria monocytogenes
- Staph aureus
- Bacillus spp.
Which hazards in raw milk are destroyed by heat treatment
- TB
- brucellosis
- salmonella
- campylobacter
Give 3 pathogens that may pose a risk despite heat tx of milk
- listeria monocytogenes
- staphylococcal aureus
- bacillus spp.
Sources listeria monocytogenes
- infected animals
- environment
- silage
- BIOFILMS in food processing environment
Infective dose of listeria and risk foods
> low
- raw milk
- chilled ready to eat foods (long shelf life when chilled, no need to cook before eating)
- sandwiches
- pate
- soft mould rippened cheese
- cooked sliced meats
- smoked salmon
Does heat Tx destroy listeria?
Not all but enough to render it safe
- post-pasteurisation contamination main risk
Listeria Clinical signs and Risk management listeria monocytogenes
> CS
- incubation period LONG ~1month
-non-invasive: flu like symptoms/asymptomatic
- invasive: abortion, meningioencephalitits in children elderly and immunocompromised
risk management
- only causes illness in limited subset of population (target at risk groups)
- industry compliance and enforcement (listeria widespread in environment but need to minimise growth to harmful levels)
- consume food in date
Why is bacillus cereus a risk
- produces spores that survive pasteurisation
- it grows at 5* and produces a toxin
> need proper refrigeration - usually spoils milk before toxin produced so not often consumed
