Transcript 1. dia - univet

Food hygiene importance of zoonoses
Salmonellosis
Ákos JÓŹWIAK
Food Hygiene Lectures, 8th semester
Basic summary
WHAT IS SALMONELLA?
What is Salmonella?
• bacterial agent responsible for a zoonotic
disease: salmonellosis
– affecting >100.000 people in EU each year
– usual symptoms: fever, diarrhea, abdominal cramps
• commonly found in intestinal tract of animals
• usual sources of infection: eggs, meat from
chicken, pigs, turkeys
• can be transferred from animals to humans via
not properly handled and cooked food
Source:
What is Salmonella?
• to combat Salmonella, it is necessary to reduce
it in animals and derived products
• EU Commission adopted an integrated
approach:
– from farm to fork
– situation of Salmonella is monitored at EU level
• joint actions already reduced the number of
infected humans by 50% in the last 5 years
– it is assumed that this is due to effective
implementation of control programs in poultry
populations
Source:
The details
WHAT IS SALMONELLA?
Salmonella
• Enterobacteriaceae family
• large number of different serotypes of
the species Salmonella enterica
– (to be precise, there are 2 species: S. enterica
and S. bongori)
– the serovar classification of Salmonella is
based on the Kauffman-White classification
scheme
– serotypes are normally denoted as a nonitalicised “species” name, e.g. Salmonella
Enteritidis, S. Senftenberg, S. Typhimurium, S.
Infantis
• rod shaped, Gram negative, non spore
forming
• motile, flagella in all directions
(peritrichous)
– exceptions: S. Gallinarum, S. Pullorum, S.
Typhi
• facultative anaerobes
3 epidemiological groups
1. Human typhoid species
–
–
typus (S. Typhi) and paratyphus (S. Paratyphi A, B, C)
adapted to humans and does not occur in other animals
2. Animal typhoid species
–
–
–
causing typhus to different animal species
S. Typhisuis pigs), S. Gallinarum, S. Pullorum (poultry)
does not occur in humans
3. Enteritis Salmonella (non-typhois species)
–
–
–
facultative pathogens for humans and animals as well
zoonosis
causing paratyphus in animals and salmonellosis in humans
Growth
•
temperature:
–
–
–
–
•
•
•
Minimum 7°C, growth greatly reduced at <15°C
Maximum 49.5°C.
Optimum 35-37°C
Some evidence for growth at 5.2°C exists, but this is serotype specific and the
data are still not universally accepted.
pH=3,8-9,5 (optimum pH=7-7,5)
water activity: minimum 0.94, optimum 0.99
atmosphere: can grow in the presence or absence of air
– growth under nitrogen is only slightly less than that under air
– grows at 8-11°C in the presence of 20-50% CO2
– growth at low temperatures is retarded in the presence of 80% CO2 compared to
air.
Survival
•
•
known to survive well in foods and on surfaces
Temperature:
– survival for >10 weeks in butter held at –23 and 25°C has been noted
– salmonellae can survive for 28 days on the surfaces of vegetables under
refrigeration
– Salmonella can survive for long periods under refrigeration
•
Water Activity:
– survival in dry environments is a characteristic of these organisms
– can survive in chocolate (aw 0.3-0.5) for months
– exposure to low aw environments can greatly increase the subsequent heat
resistance
•
pH: Salmonella are less acid resistant than E. coli
Inactivation
•
Freezing:
–
–
•
Heat treatment (D-times):
–
–
–
–
•
60°C usually 2-6 min
70°C usually 1 min or less
Extremely high D times have been reported for experiments with milk chocolate. Values
reported were up to 1050 min at 70°C, 222 min at 80°C and 78 min at 90°C. This also
applies to other low water content foods
Some rare serotypes (e.g. S. Senftenberg) are significantly more heat resistant than the
others, which are not particularly resistant to heat
Water activity:
–
•
death occurs during the freezing process, but those that survive remain viable during frozen
storage
freezing does not ensure the inactivation of salmonellae in foods
at water activities less than that allowing growth the decline in numbers is reduced at lower
aw values
Preservatives:
–
growth was inhibited in the presence of 0.1% acetic acid (pH 5.1)
The illness
WHAT IS SALMONELLOSIS?
Salmonellosis
•
Incubation: 6-48 hours (usually 12-36 hours)
•
Symptoms: Diarrhea, abdominal pain, vomiting, nausea and fever lasting 17 days
– hospitalisation rate estimated at 22.1%
– fatality rate 0.8%
•
Risk Groups: the young, old, and immunocompromised are particularly at
risk. In addition people of less privileged socioeconomic groups and those
living in higher population densities are more at risk
•
Long Term Effects:
–
–
septicaemia and subsequent non-intestinal infections can occur
reactive arthritis may occur 3-4 weeks after gastrointestinal symptoms
Salmonellosis
•
Infective dose: generally recognised doses to cause disease at high attack
rates are in the range of 105-106 cells.
– Low attack rates have been observed sometimes (4-6 cells)
– Foods with high fat content, like chocolate or peanut butter may protect cells
from gastric juices so permitting a lower dose than usual to cause infection.
•
Treatment: the infection is usually self-limiting although fluid replacement
may be required.
– Antibiotic treatment seems to be either ineffective or results in relapse or
prolonged faecal shedding
– Certain groups, e.g. new born children, may benefit from antibiotic treatment.
Sources
•
Human sources: faeces of infected people contain large numbers of the organism
and shedding may continue for up to 3 months.
–
•
Animal sources: some serotypes are confined to particular animal reservoirs, but
many are capable of crossing between species to cause disease in man, often via
food.
–
–
–
–
•
most Salmonella infections in animals are symptomless
poultry and pigs are regarded as major reservoirs of the organism
animal feeds made from animal products may be contaminated by Salmonella
Salmonella can also be found in fish, terrapins, frogs and birds.
Food sources:
–
–
•
The median period for shedding is 5 weeks, <1% become chronic carriers
meat or other products derived from infected animals
other animal products, e.g. unpasteurised or re- contaminated pasteurised milk and dairy
products, can also act as vehicles
Environmental sources: Salmonella shed in faeces can contaminate pasture, soil and
water.
–
–
It can survive for months in the soil.
Contamination in the environment can serve to act as a source of infection of other animals.
Salmonellosis
CURRENT SITUATION
Status
•
•
Out of the about 2500 serotypes, certain ones such as S. Enteritidis (SE)
and
S. Typhimurium (ST) are responsible for a high number of human disease
cases.
Food contaminated by salmonellas are still the major source of human
foodborne diseases in the EU
–
though, in the past 5 years a definite reduction tendency
can
be seen ininthe
Incidence of
salmonellosis
EU corresponding
2004-2008
statistics
Source: EFSA Zoonosis report
200000
180000
160000
140000
120000
100000
80000
60000
40000
20000
0
2005
2006
2007
2008
2009
Number of salmonella species-induced diseases in
Hungary (Source: OEK Epinfo, Zoonosis report)
16 000
14 000
12 000
10 000
8 000
6 000
4 000
2 000
0
1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009
Reducing human salmonellosis
• The two main pillars of the Community-endeavour in reducing the
number of salmonella-induced human diseases are:
– Obligatory salmonella reducing program in the primary production, affecting the
stocks
– Microbiological standards for the food industry
• The aim is to supply the food industry, the catering industry and
kitchens with salmonella-free raw material.
• An important component of the reduction program is the availability
of continuously updated epidemiological data base.
Reducing human salmonellosis
SALMONELLA REDUCTION
PROGRAMS IN POULTRY FLOCKS
The beginnings
• Monitoring/protection program (SE/ST) has been existing since 1997
in Hungary.
• The rules of the early reduction program were issued in an offical
guideline („White Book”)
– entitled „Integrated quality assurance system against salmonelloses for
the poultry sector in Hungary”.
• The guideline included the demand for the establishment of a
corresponding Hungarian Act in harmony with the related EU
Regulation.
Hen breeding flocks
• Begining of the National reduction
program: 2007
• Sampling bi-weekly
• Goal (1003/2005/EC):
– The percentage of infected flocks with five indicated serotypes –
SE, ST, SI, SH, SV (S. Enteriditis, Typhimurium, Hadar, Infantis
and Virchow ) – should have been reduced to 1% until 31
December 2009.
• Aim (200/2010/EC):
– From 01 January 2010 the aim is still to reduce the infection rate
to maximum 1% in adult breeding flocks.
Hen breeding flocks
• Based on earlier data, the „initial” estimated
infection rate was 6% (SE/ST).
– this was reduced to 3% by the end of 2007
– and to 1.44% in 2008
– and 0.4% in 2009.
• the infection rate for the 5 main serotypes was
1.6% in 2009
• and for all the serotypes it was 3.4% in 2009
Hen breeding flocks
Előfordulási gyakoriság
8
7
6
5
SE/ST
%4
5 kiemelt szerotípus
Összes szerotípus
3
2
1
0
2007
2008
2009
2010. I.
Hen breeding flocks
• The infection rate in Hungary for SE/ST was
0.24% and for the 5 serotypes it was 0.85% by
the end of 2010.
• The Community aim, therefore was satified.
• The infection rate was 2.2% for all the serotypes.
Table egg-producing flocks
• A survey in 2006 showed 34% SE/ST
infection rate in the Hungarian layer flocks
• Begining of the National Reduction
Programme: 2008
• Aim (1168/2006/EC):
– Only SE/ST
– Three times sampling in the production cycle
• The limit was set based upon the 2006 baseline study:
– The aim for layer flocks was to reach 13.16% SE/ST infection
rate by 31 December.
– A further goal was to reach 2% infection rate (according to
Regulation 1168/2006/EC, section 1. point (1) b).
Table egg-producing flocks
• The SE/ST infection rate was 8.66% by the end of 2008.
– 1068 stocks were included in the programme.
• By the end of 2009, the SE/ST infection rate was 3.16%,
– for all the serotypes, it was 7.35%.
– Close to 10 million birds were vaccinated (about 100%
vaccination rate).
• By the end of 2010, the SE/ST infection rate became
1.4% (the related Community requirement was satisfied)
– The infection rate for all the serotypes was 5.52%
Table egg-producing flocks
50
Infec on rate
40
30
20
%
10
0
All serotypes
SE/ST
baseline
43,7
34
2008
17,5
8,3
2009
7,35
3,16
2010
5,52
1,4
The aim for layer flocks was to reach 13.16% SE/ST infection rate by 31
December, 2010 but it was 3.16 % already in 2009. A further goal was to
reach 2% infection.
Broiler flocks
(Gallus gallus broiler)
• Begining of the National Reduction
Programme: 2009
• Aim (646/2007/EC):
– Only SE/ST
– Sampling within 3 weeks before slaughter
• The number of SE/ST positive flocks should be reduced
below <1% by 31 December 2011.
• From the second half of year 2011, food safety limit
value will be introduced for fresh broiler and turkey meat
Broiler flocks
(Gallus gallus broiler)
• About 4000 flocks were included
• The SE/ST infection rate was 0.45% by the end
of 2009
– and it was 32.9% for all the serotypes.
• By the end of 2010, the SE/ST infection rate was
0.08%, thereby the Community aim was
satisfied.
– The infection rate for all the serotypes was 16.9%
Salmonella prevalence in broiler flocks
%
80
70
60
50
40
30
20
10
0
Infec on rate
baseline
2006
2009
2010
All serotypes
68
32,9
16,9
SE/ST
8,1
0,45
0,08
The aim planned for broyler flocks until 31 December 2011, was fulfilled
already in 2009 (0.45 %)
Prevalence of Salmonella in fresh broiler
meat (25g sample from the product)
1
0,9
0,8
0,7
67,0%
0,6
0,5
43,0%
0,4
41,6%
32,0%
0,3
0,2
0,1
SE+ST; 2,0%
SE+ST; 2,5%
SE+ST; 1,2%
SE+ST; 0,1%
2006
2007
2008
2009
0
Prevalence data on Salmonella in poultry
meat (neck skin samples)
1
0,9
86,0%
0,8
0,7
60,0%
0,6
0,5
0,4
0,3
0,2
0,1
SE+ST; 2,1%
SE+ST; 0,9%
0
2008 baseline
2009
25 gramm pooled-samples from 3 birds’ neck skin
Turkey flocks
• Begining of the National Reduction
program: 2010
• Aim (584/2008/EC):
• Breeder turkey
– The quantity of SE /ST infected breed-turkey flocks must be
reduced below 1% by 31 December 2012
– Sampling: three-weekly
• Meat turkey
– The ratio of meat turkey infected with SE /ST must be reduced
below 1% until 31 December 2012
– Sampling within 3 weeks before slaughter
Data on Salmonella testing in turkey flocks
Meat turkey
Breeder turkey
90
80
70
60
50
40
30
20
10
0
100
80
81
60
40
15,4
13,7
0
0
20
32
3,4
0
0
2007 Baseline
All serotypes
2010
SE/ST
2007 Baseline
All serotypes
2010
SE/ST
Prevalence data of Salmonella in fresh
turkey meat
100%
90%
80%
70%
60%
50%
40%
30%
20%
13,2%
11,4%
13,4%
2006
2007
2008
17,0%
10%
0%
2009
The big competition
SALMONELLA VS.
CAMPYLOBACTER
Salmonella spp. and Campylobacter prevalence study
of the European Union in broiler poultry at the
slaughterhouses
• A harmonized Community reduction program must be based
on reliable and comparable data
• According to Decision 516/2007 EC, the examinations had to
be carried out in all Member States applying standardized
sampling and examination methods financied by the
Community
• 26 Member States + Norway and Switzerland
• 561 salughterhouses
• 10.132 slaughtered items
• Execution: 2008
• Evaluation: 2010
Sampling
• The sampling pattern was based on the previous year
slaughter data
• Determination of the prevalence of Salmonella and
Campylobacter spp. in slaughtered animal body
– neck-skin of the slaughtered bird, this is the best indicator for the
potential contamination
– presence/absence+ quantitative examination
• The survey of the occurrence of Campylobacter spp. in
slaughtered flocks
– ten pooled appendices samples/slaughter-item
– only presence/absence examination
Hungarian results
SALMONELLA VS.
CAMPYLOBACTER
Prevalence of Salmonella spp. in samples,
distribution according to serotypes
Serotype
Salmonella-positive samples
N
%
Salmonella spp.
275
85.7%
S. infantis
269
83.8%
S. enteritidis
13
4.0%
S. indiana
2
0.8%
S. thompson
4
1.2%
S. typhimurium
1
0.3%
In half of cases, SE occurs altogether with S. infantis
The measure of contamination with
Salmonella spp.
Quantities of Salmonella in positive samples (cfu/g)
80%
70%
60%
50%
40%
30%
20%
10%
0%
72,4%
12,0%
<10
>10-100
6,2%
>100-1000
3,6%
>1000-10 000
3,6%
>10 000-100
000
Distribution of Salmonella-positive
samples according to the type of
chilling
Type of
chilling
Sample
number
Salmonella positive
neck-skin
Average Salmonella
count
N
N
%
log10/g
Air-chilling
257
216
84.0%
1.08
Spray-chilling
46
44
95.7%
0.89
Immersion
18
15
83.3%
0.78
Total
321
275
85.7%
Sesonal prevalence of Salmonella and
Campylobacter (neck-skin)
1,00
0,90
0,80
0,70
0,60
0,50
0,40
0,30
0,20
0,10
0,00
I.
II.
III.
IV.
V.
VI.
Campylob. pozitív nyakbőr
VII.
VIII.
IX.
Salm. pozitív nyakbőr
X.
XI.
XII.
EU results
SALMONELLA VS.
CAMPYLOBACTER
Summarised data
• More than 5.3 billions of broiler chikens were
slaughtered in the Member States in 2008
• UK 816 millions, FR 706 millions, ESP 594 millions
• Average Salmonella prevalence: 15.6% (0-85%)
• SE+ST: 3.6% (0-9.3%)
• The most frequent 4 types SI, SE, S. Kentucky, ST
• The Salmonella prevalence (15.6 %) is much lower than
the Campylobacter prevalence (75.8%), except in HU
• No interrelationship between the prevalance of the 2
causatives was found in the Member States
Salmonella spp. prevalence data in the EU
Comparison of Salmonella prevalence-data obtained at the
slaughterhouses and at survey of the flocks
EU survey- conclusions
• The Campylobacter contamination both of broiler flocks
and of poultry meat is outstandingly high
• There is no relationship between salmonella positivity
and contamination with campylobacter
• Our epidemiological knowledge is still poor, we do not
know precisely the points of potential intervention for
reducing the prevalence of Campylobacter in the flocks
or at the slaughterhouse
• At the moment, we do not plan harmonized
preventive/reduction program for Campylobacter
• The results of examinations clearly indicate that the
measure of Campylobacter contamination is varying
among slaughterhouses
EU survey- conclusions II
• There is debate on the possible introduction of a quantitative
technological criterium (m= 1.000 cfu/g, M= 10.000 cfu/gramm) -this
is postponed until the preparation of EFSA opinion (March 2011)
• The responsibility of consumers and public caterings in reducing the
incidence of both salmonella and campylobacteriosis (careful heattreatment, prevention of cross-contamination)
• The epidemilological status of Member States is very heterogenous
• The individual (Member State) regulatory route is open but the
Community aim is not modified at the moment (in breeding flocks 5
important serotypes, in the other flock types SE/ST.
FOOD SAFETY ASPECTS
Microbiological criteria
• The microbiological requirements for poultry meat and
products are described in Regulation 2073/2005/EC.
• The Regulation uses two different types of food safety
criteria:
– Food-safety criteria
• In case of food-safety criterium, if it is not satisfied, the food must
not be marketed or must be withdrawn.
– Technological-hygiene criteria
• The technological-hygiene criterium determines the microbiological
acceptibility of the production technology and not of the product. If
the criterium is not satisfied, the product may be marketed but the
technology must be improved to prevent repeated failure.
Criteria for Salmonella
• Regulation 2073/2005/EC prescribes for the measure/threshold of
contamination with salmonellas in fresh poultry meat (Gallus gallus
and turkey) only technological-hygiene criterium.
– For other poultry species no criterium is existing.
• Neck swab sampling is required at the slaughterhouse. Five
samples are taken weekly or in appropriate cases, bi-weekly (from 3
animals per pooled sample).
– According to the criterium, 7 sample may be positive from 50 samples taken
through 10 consequtive weeks.
• If the number of positives is over 7, the meat may be marketed and
the slaughterhouse must make measures for satisfying the criterium
in the future.
Regulatory changes in foods
• Plans were: according to Appendix D in
Regulation 2160/2003/EC, from 2011 fresh
broiler and turkey meat is not permitted for
marketing, if the requirement of 0/25 gramm
Salmonella is not satisfied
• Preparation of feasibility study in 2009
• The limit value cannot be introduced in the
present form
• Regulation 2073/2005/EC will contain the
detailed regulation
Amendment of Regulation
2073/2005/EC
• Food safety limit value is introduced for the SE/ST and for the
monophasic ST-like strains (0/25 gramm, 5 samples)
• For the other serotypes, the existing technological criterium is
maintained, but c value is reduced from 7 to 5 (the present value
cannot be satisfied by half of the Member States)
• Sampling is weekly but in case of appropriate results (after 30
weeks), the sampling rate may be reduced to bi-weekly sampling
• At slaughterhouses still the neck-skin is sampled, salmonella
positives must be serotyped and if it is SE/ST, measures are taken
according to the safety criteria
• In cutting plants also weekly sampling is performed, here only food
safety criterium will be applied
Amendment of Regulation
2073/2005/EC
• The product groups for sampling must be selected on
ground of risk (analysis)
• The sample should represent the skin, but at least
(other) surfaces
• The sampled items may be marketed without waiting for
the result, but in case of SE/ST positivity, the measures
prescribed in the Regulation for cases when the safety
criterium is not satisfied, must be taken
• In the other product groups, the safety criterium is not
restricted to the two distinguished serotypes
• The Member States (after notification) may introduce
individual regulation in their own territory also for other
serotypes, if it seems to be necessary, but this individual
regulation must not be applied for products originating
from another Member State
RESPONSIBILITY OF
CONSUMERS
Responsibility of consumers
• the reduction programme includes only the most
risky serotypes
• therefore from part of consumers, the
precautionary principle should be applied
–
–
–
–
–
separation of fresh and prepared/processed meat,
washing of tools,
disinfection,
frequent hand-wash
the usual, well-proved roasting, boiling
Role of consumers
Source: WHO
Role of consumers
Source: WHO
Role of consumers
Source: WHO
[email protected]
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ATTENTION