This document summarizes a study quantifying Salmonella contamination in pig slaughterhouses and pork markets in Vietnam. Salmonella was detected in 36.9% of samples from slaughterhouses and 41.4% of samples from markets. Higher prevalence was found in District C markets compared to Districts A and B. Salmonella numbers on carcasses, worker hands, and cutting boards were generally low but detectable. Potential risk factors for contamination were examined but none were found to be statistically significant. The study aimed to understand Salmonella contamination in the pork production chain and its relationship to human health.

1. VETERINARY PUBLIC HEALTH CENTRE FOR ASIA PACIFIC
Joint Master of Veterinary Public Health_5th Batch, 2011-2013
QUANTIFYING S l ll IN PIG
VIETNAM
QUANTIFYING Salmonella spp. IN PIG
SLAUGHTERHOUSES AND PORK MARKETS
ASSOCIATED WITH HUMAN HEALTH IN HUNG YEN,
VIETNAM
MVPH student: Sinh Dang Xuan (student ID: 541435808)
Advisors: Prof. Dr. Reinhard Fries (FUB)
Dr. Tongkorn Meeyam (CMU)
9/10/2013 1

2. 1. Rational and background
2. Objectives
3. Materials and Methods
4. Results
5. Discussions
6. Conclusions
2
Contents
9/10/2013

3. 39/10/2013

4.  Gram-negative
 Family Enterobacteriaceae
 2 Species: S. enterica and S. bongori
 Serotypes: > 2,600 (Guibourdenche et al., 2010),
• Typhoidal Salmonella (S.Typhi, S.Paratyphi A, B, C)
• Non-typhoidal Salmonella (Food borne pathogens)
Picture source: http://www,odec,ca/projects/2005/qiuc5c0/public_html/Untitled-12,htm 4
Salmonella Microbiology
9/10/2013

5. -Humans: as a foodborne disease, in the world
 93.8 million cases/year
155,000 deaths/year
(Majowicz, 2010)
-Health care costs, loss or reduce livestock and
food production
5
Human Salmonellosis
9/10/2013

6. 6http://www.cdc.gov/foodnet/data/trends/tables/2012/table2a-b.html#table-2a
121
155
193
1,082
1,234
2,138
6,793
7,800
0 2,000 4,000 6,000 8,000 10,000
Listeria
Yersinia
Vibrio
STEC
Cryptosporidiu
m
Shigella
Campylobacter
Salmonella
, , , , ,
Human Salmonellosis
Figure 1 Number of laboratory-confirmed bacterial and
parasitic infections by pathogens (FoodNet) in 2012
9/10/2013

7. 7
Human Salmonellosis
http://www.cdc.gov/foodborneburden/trends-in-foodborne-illness.html
Figure 2 Changes in incidence of laboratory-confirmed
bacterial infections, United States, 2010 compared with
1996–1998
9/10/2013

8.  Contaminated food/vegetables/fruits (Hughes et al.,
2007; Hendriksen et al., 2004; Barber et al., 2002)
 Pork: one of major sources of human
foodborne after egg and poultry meat (EFSA, 2008)
8
Salmonella in food
Picture source: http://vietpress.vn/201301290235670p46c76/giam-gia-thit-ga-truoc-va-sau-tet.htm
http://www.xaluan.com/modules.php?name=News&file=article&sid=5272749/10/2013

9. 9
Figure 3 Estimated contribution of broilers, pork and table
eggs in Salmonella infections in the general population (cases per
100,000) in Denmark in the period 1988 – 2004
Salmonella in food and Pork
Source: The EFSA Journal (2006), 341, 1-1319/10/2013

10. 10
Table 1 Causes and outbreaks of food poisoning in
Vietnam, 2007-2011
Food poisoning outbreaks in Vietnam
Source: VFA, Vietnam, 20129/10/2013
Year
Causes for food poisoning outbreaks (in %)
Micro-
biological
Chemi-cals
Natural
toxins
Non-Iden-
tification
2007 15 (6.1) 2 (0.8) 54 (21.9) 176 (71.3)
2008 16 (7.8) 1 (0.5) 52 (25.4) 136 (66.3)
2009 45 (29.6) 8 (5.2) 37 (24.7) 62 (40.5)
2010 52 (30.1) 13 (7.8) 59 (35.0) 49 (28.5)
2011 40 (28.2) 8 (5.8) 38 (26.8) 56 (39.4)
Average 34 (18.3) 6 (3.5) 48 (21.6) 96 (52.1)

11. 11
Pig slaughterhouses, pork markets and
Salmonella contamination
Photo by: Sinh DX9/10/2013
Slaughter equipments
Pigs from farm
Workers/ people
SH Environment
Market environment
Transportation
Sellers/people
Slaughter water
Water at shop
Shop equipments
Carcass from SH
Transportation
Transportation
FARM
SLAUGHTERHOUSEMARKET
HOME

12. -15% - 95%: on carcasses
-16% - 62%: in water, on the floor, weighting
bowls, cutting boards
-33% - 69%: in pork at market
(Le Bas, 2006; Takeshi K,2009)
12
Salmonella contamination in slaughterhouses
and market in Vietnam
9/10/2013

13. 139/10/2013

14.  To detect the Salmonella spp. prevalence and
concentration on pig carcass at slaughterhouse
and pork at market
 To identify risk factors of Salmonella spp.
contamination in the pork production chain
 To explore people’s and relevant stakeholders
perception related to Salmonella contamination
with the potential risks in practice
14
Objectives of study
9/10/2013

15. 159/10/2013

16. Hung Yen province
16
Map of Vietnam
Source: http:/www, trelangkienviet,com
5
Study location
9/10/2013

17. 179/10/2013
Study location

18. 18
Study scope
Data collection
‐ Checklist
‐ Questionnaire
‐ Focus group discussion (FGD)
‐ In‐depth interview (IDI)
Data analysis
Sample collection
Salmonella identification
(ISO 6579:2002/Amd
1:2007)
Salmonella quantification
(3‐Tube MPN method)
ISO 21528‐1:2004
Carcass Pork Environmental swabs
(Ccutting board, Hands)
3 Pig Slaughterhouses &
Markets (4 visits each)
Study duration: From January to May, 2013
9/10/2013 Figure 4 Study scope and process

19. 19
Sampling site
Lairage
Evisceration
Restrain & Bleeding
Cut pork at market
9/10/2013
Scalding & Dehairing
Transportation
FARM
SLAUGHTER
-HOUSE
MARKET
Washing & wiping
Splitting
Transportation
Carcass
Workers hands
Cutting board
Cutting board
Pork
Sellers hands
HOME Pork at household
Transportation

20. Sample collection
20
Sample types Unit/sample n
Carcass surface 400 cm2 47
Belly skin 25 g 16
Workers’ hand 2 hands 12
Cutting board 25 cm2 12
Pork 25 g 63
Sellers’ hand 2 hands 12
Cutting board 25 cm2 12
Total 174
Table 2 Number and types of sample collection
9/10/2013

21. 25g Belly skin
or Pork
Carcass or
Environmental swabs
Homogenization
+225ml BPW +100ml BPW
Interpretation
of Result
Suspected
colonies on
NA
Biochemical &
Serological
Confirmation
Microbiological Analysis
21Figure 5 Salmonella identification and quantification
Salmonella quantification
10‐1 10‐2 10‐3
1 ml
9 ml MKTTn
3 drops
MSRV MSRV
Salmonella identification
XLT4 BGA
XLT4 BGA
3‐tube MPN
method
9/10/2013

22. Questionnaire:
- No. of pigs
- Transport time, duration, distance
- Time in lairage, …
 Checklist:
- Hygienic practice/measures
- Biosecurity
22
Data collection
9/10/2013

23. 23
Data collection
9/10/2013
Qualitative tools
Focus group discussion Key topics
Slaughter workers (2
FGD)
- Hygienic practice in slaughtering
- Perception, knowledge about pork borne diseases
Pork sellers (3 FGD) - Pork selling practice
- Pork borne diseases (knowledge, awareness,
perception)
In-depth interview
People living around
slaughterhouse (9 IDI)
- Advantages and disadvantages of slaughterhouse
Pork consumer (9 IDI) - Criteria for selecting pork
- Pork borne diseases (knowledge, awareness,
perception)
Public health staff (3 IDI) Food safety and zoonotic management & collaboration
Veterinary staff (3 IDI) Food safety and zoonotic management & collaboration
FGD = Focus Group Discussion; IDI = In-depth interview

24. - Descriptive statistic
- OR and χ2 test for risk factors
- Significant consideration at p<0.05
Using R Studio (0.96.316) and MS Excel-2007
24
Data analysis
9/10/2013

25. 259/10/2013

26. General information of slaughterhouses
Table 3. Mean of variables recorded from pig transportation
and lairage time (n=12 visits)
Variables Unit Mean ± SD Range
No. of pig transport/time Head 23 ± 7 17 - 40
Transport duration Hour 1.76 ± 1.24 0.5 – 4.17
Transport distance Km 60.8 ± 50.4 15 – 150
Resting time in lairage Hour 13.1 ± 4.17 5 - 17
SD= Standard deviation
Capacity: 10-40 pigs/day; 4-6 workers; slaughter: 1-5 a.m
269/10/2013

27. 27
Sample types
Prevalence_%
(No. positve result/n)
SH A SH B SH C Overall
Carcass(*)
23.8
(5/21)
38.1
(8/21)
42.9
(9/21)
34.9
(22/63)
Workers’ hand
25.0
(1/4)
100
(4/4)
25.0
(1/4)
50.0
(6/12)
Cutting board
25.0
(1/4)
50.0
(2/4)
25.0
(1/4)
33.3
(4/12)
Overall
24.1
(7/29)
48.3
(14/29)
37.9
(11/29)
36.9
(32/87)
Table 4. Salmonella prevalence from different sample
types in 3 slaughterhouses
Salmonella prevalence
(*) include swab and belly skin, SH= Slaughterhouse
9/10/2013

28. Fig 6. Overall Salmonella prevalence from 3
slaughterhouses
24.1
48.3
37.9
0
10
20
30
40
50
60
SH A SH B SH C
Percent
Slaughterhouse
28
Salmonella prevalence
No significant difference (p=0.403, χ2 test) among 3
slaughterhouses
9/10/2013

29. 29
Table 5. Salmonella prevalence from different sample
types in markets
Salmonella prevalence
9/10/2013
Sample type
% Prevalence (No. Salmonella positve/n)
District A District B District C Overall
Pork
14.3
(3/21)
47.6
(10/21)
66.7
(14/21)
42.9
(27/63)
Sellers’ hands
25.0
(1/4)
0.0
(0/4)
75.0
(3/4)
33.3
(4/12)
Cutting board
25.0
(1/4)
25.0
(1/4)
75.0
(3/4)
41.7
(5/12)
Overall
17.2
(5/29)
37.9
(11/29)
69.0
(20/29)
41.4
(36/87)

30. 30
Fig 7. Salmonella prevalence from different sample types in markets
Salmonella prevalence
9/10/2013
17.2
37.9
69.0
0
10
20
30
40
50
60
70
80
District A District B District C
Pork markets
Percentage
Statistically significant difference about Salmonella prevalence on pork
samples among 3 districts (p-value=0.0018, Fisher’s exact test)

31. 23.5
46.7
53.3
34.9
14.3
47.6
66.7
42.9
0
10
20
30
40
50
60
70
District A District B District C Overall
Carcass Pork
31
Fig 8. Salmonella prevalence on carcass in slaughterhouses
and on pork in markets in 3 districts
Salmonella prevalence
9/10/2013
Percentage
Salmonella prevalence

32. Salmonella number
Table 6. Salmonella number from different sample types
in 3 slaughterhouses
Sample types Unit No. of Salmonella 95% CI
Carcass surface MPN/cm2 <0.075 0.0-0.24
Belly skin MPN/g <0.3 0.0-0.95
Workers’ hand MPN/hand 7.0 1.0-50.0
Cutting board MPN/cm2 <1.2 0.0-3.80
329/10/2013

33. Salmonella number
Sample types Unit No. of Salmonella 95% CI
Pork MPN/g < 0.3 - 15 3.7 - 42.0
Sellers’ hands MPN/hand 4.6 0.7 - 19.0
Cutting board MPN/cm2
0.368 0.056 - 1.52
339/10/2013
Table 7. Salmonella number from different sample types
in markets in 3 districts

34. Salmonella number
Table 8. Salmonella number in slaughterhouse and market
349/10/2013
Sample Unit
Number of Salmonella
Slaughterhouses Markets
Carcass - Pork MPN/g < 0.3 < 0.3 - 15
Worker - Seller hand MPN/hand 7.0 4.6
Cutting board MPN/cm2 < 1.2 < 0.368

35. 35
Related risk factors
Table 9. Potential risk factors related to Salmonella
contamination in slaughterhouses
Potential risk factors of Salmonella contamination were not found
significantly diference.
CI: Confident interval
9/10/2013
Factors OR (95% CI) p -Value
Using water tank 2.18 (0.67-7.07) 0.191
Slaughter square area (≤ 50 m2) 1.67 (0.57-4.95) 0.350
Free entry slaughter area 2.18 (0.67-7.07) 0.191
Private farm type 2 (0.29-13.74) 0.631
Pig transport distance (> 30 km) 1.33 (0.2-9.08) 1.00
Time arrived at lairage in the morning 5.7 (0.53-61.41) 0.179
Disease in farm area
(in 6 months recently)
10.5 (1.03-107.2) 0.063
Number of pigs on processing
at the same time (>2 pigs)
1.2 (0.41-3.66) 0.709

36. 36
Related risk factors
Table 10. Potential risk factors of Salmonella contamination in markets
(*) Statistically significant diference. CI: Confident interval
9/10/2013
Observation OR (95% CI) p-value
Table surface pork contacted is wood 6.6 (2.02 - 21.55) 0.002*
Table surface pork contaced is inox/steel 0.19 (0.02 - 1.7) 0.223
Usually use insect control equipments
while selling
1.76 (0.6 - 5.23) 0.303
Using meat grinder 2.41 (0.8 - 7.22) 0.113
Using bucket (mobile) water in shop 4.46 (1.46 - 13.65) 0.007*
Cutting on table surface 4.46 (1.46 - 13.65) 0.004*
Shop sells retail only 0.48 (0.17 - 1.38) 0.170
Shop sells both retail and wholesale 4.71 (1.28 - 17.27) 0.030*
Contain pork in basket to transport to the
shop
2.8 (0.98 - 8) 0.052
Wash table end of selling time by water
and detergent
0.44 (0.1 - 1.84) 0.326

37. 37
Salmonella serotypes
9/10/2013
Table 11. Salmonella serotypes circulated in 3 pig
slaughterhouses and sample types
Serotype Carcass
Workers
hands
Cutting
board
Total Percentage
S. Anatum 1 1 3.2
S. Derby 3 2 1 6 19.4
S. Give 1 1 2 6.5
S. London 4 4 12.9
S. Meleagridis 2 1 1 4 12.9
S. Rissen 2 2 1 5 16.1
S. Typhimurium 5 1 6 19.4
S. Weltevreden 3 3 9.7
Total Poly I 31 100
Poly II 1

38. 38
Salmonella serotypes
9/10/2013
Fig 9. Salmonella serotypes distribution in 3 pig
slaughterhouses
S. Anatum
3.2%
S. Derby
19.4%
S. Give
6.5
S. London
12.9%
S. Meleagridis
12.9%
S. Rissen
16.1%
S. Typhimurium
19.4%
S. Weltevreden
9.7%

39. 39
Salmonella serotypes
9/10/2013
Table 12. Salmonella serotypes circulated in marrkets in 3
districts and sample types
Serotype Pork
Sellers
hands
Cutting
board
Total Percentage
S. Anatum 4 1 1 6 16.7
S. Bovismorbificans 1 1 2 5.6
S. Derby 6 1 7 19.4
S. Give 1 1 2.8
S. London 4 1 5 13.9
S. Meleagridis 4 1 1 6 16.7
S. Rissen 4 1 5 13.9
S. Stanley 2 2 5.6
S. Weltevreden 2 2 5.6
Total 36 100

40. 40
Salmonella serotypes
9/10/2013
Fig 10 Salmonella serotypes distribution in markets in 3
districts
S. Anatum
16.7%
S.
Bovismorbificans
5.6%
S. Derby
19.4%
S. Give
2.8%
S. London
13.9%
S. Meleagridis
16.7%
S. Rissen
13.9%
S. Stanley
5.6%
S. Weltevreden
5.6%

41. 41
Salmonella serotypes
9/10/2013
Fig 11 Salmonella serotypes distribution in Slaughterhouse
and in Markets in 3 districts
16.7
5.6
19.4
2.8
13.9
16.7
13.9
5.6
5.6
S. Anatum S. Bovismorbificans
S. Derby S. Give
S. London S. Meleagridis
S. Rissen S. Stanley
S. Weltevreden
Markets
3.2
19.4
6.5
12.9
12.9
16.1
19.4
9.7
S. Anatum S. Derby
S. Give S. London
S. Meleagridis S. Rissen
S. Typhimurium S. Weltevreden
Slaughterhouse

42. 42
Salmonella serotypes
9/10/2013
Fig 12 Salmonella serotypes distribution in slaughterhouse
and markets
1
3
1
4
2
2
5
3
3
1
2
3
1
4
6
1
4
4
4
2
2
2
2
1
1
2
1
0 2 4 6 8 10 12 14
S. Anatum
S. Bovismorbificans
S. Derby
S. Give
S. London
S. Meleagridis
S. Rissen
S. Stanley
S. Typhimurium
S. Weltevreden
Pig carcass at SH
Environment at SH
Pork at MK
Environment at MK

43. 43
Collected Data Frame
9/10/2013
Table 13 Groups and participants for IDI, FGD, checklists &
questionnaires
Tools/
groups/stakeholders/places
No. groups
/districts
Total participant/
interviewee/checklist
Quantitative
Questionnaire
Pig origin questionnaire
(slaughterhouse owner)
3 12
Observation (checklist)
Pig slaughterhouse 3 3
Pork shop 3 19
Qualitative
Focus group discussion
Slaughter worker 2 10
Pork seller 3 15
In-depth interview
People living around slaughterhouse 3 9
Pork consumer 3 9
Public health staff 3 3
Veterinary staff 3 3
FGD = Focus Group Discussion; IDI = In-depth interview

44. 44
Results from explore people and relevant stakeholders’ perception
related to food safety with the potential risks in practice
9/10/2013
* Focus groups discussions in Slaughterhouse workers
1. Regulation: No specific regulation or rule, used “internal rule”
2. Training program on food safety and slaughtering process: learning by
doing, not officially from training
3. Perception, knowledge about pig diseases: FMD, PRRS, fluke and worm,
pigs diarrhea: Two main important: FMD and PRRS
4. Zoonoses knowledge and perception: cysticercosis and leptospirosis, but
were not really concerned. FMD and PRRS: misperception
5. Origin of information: mass media, newspaper, internet or TV. Vet and
or public health services were not mentioned
6. Observed human illness related pig or pork: No observed cases of
illness or diarrhea in last 6 months.

45. 459/10/2013
* Focus groups discussions in Slaughterhouse workers
Potential risks District A District B
Feces in lairage 1 7
Feces on live pigs 1 3
Puncture intestine 2 2
Feces on the bleeding area 2 4
Wash intestine at slaughter areas 2 5
Water source 3 1
Boots at all places 6 7
Transport vehicle 7 9
Cloths 5 8
Table 14 Ranking given potential risks to microbial
contamination on carcass

46. 469/10/2013
* Focus groups discussions in Pork sellers
FGD for this actor were organized in each of 3 selected districts
1. Prefer to use wood surface tables in pork shop: in stead of other types
2. Cloth usually used to dry pork, clean equipment, hand or table: All three
sellers groups stated using during selling time
3. Glove and mask using: a perception to buyers aware of sellers’ health
problem.
4. Leftover pork: sell it for the shop at a relatively lower price, processed into
other foods
5. Pork quality and zoonoses: pork quality related to the way slaughtered pig
* PRRS and FMD, CSF, pastuerellosis, leptospirosis, cysticercosis
Misperception on FMD, CSF
6. Observed human illness related pig or pork: None of the participants

47. 479/10/2013
* Focus groups discussions in Pork sellers
Potential risks District A District C
Cleanness of surrounding shop area 1 4
Insects (files, bluebottle, ant, cockroach) 2 5
Dirty /waste water drain next to shop 2 2
Cleanness of table surface 3 1
Water for wash hand, knife, table 4 4
Bags - Basket (pork transport) 5 3
Cloths used many times in selling day 6 2
Pork transportation to the market 7 3
Clothes, shoes of sellers 8 6
Table 15 Ranked potential risk factors related to microbial
contamination on pork at market

48. 489/10/2013
* In-depth interview in People living around slaughterhouse
(1) Advantages of slaughterhouse’s presence in their living area:
Issues All District A District B District C
Provide job 9/9 3/3 3/3 3/3
Available pork to buy 7/9 1/3 3/3 3/3
Business opportunities 4/9 0/3 1/3 3/3
Benefit for you 0/9 0/3 0/3 0/3
Table 16 Advantages of slaughterhouse’s presence
(Yes/Total)

49. 499/10/2013
* In-depth interview in People living around slaughterhouse
(2) Disadvantages of slaughterhouse’s presence in their living area:
Issues All District A District B District C
Noise 0/9 0/3 0/3 0/3
Polluted environment 1/9 1/3 0/3 0/3
Dust 1/9 0/3 1/3 0/3
Polluted air 2/9 2/3 0/3 0/3
Flies/Mosquitoes 2/9 0/3 1/3 1/3
Smell 3/9 1/3 0/3 2/3
Polluted water 3/9 2/3 0/3 1/3
Animal disease spread 3/9 2/3 0/3 1/3
Health effect 5/9 2/3 1/3 2/3
Table 17 DisaAdvantages of slaughterhouse’s presence
(Yes/Total)

50. 509/10/2013
* In-depth interview in Pork consumers
Table 18 Result of criteria ranking in pork selection
Criteria No. of respondents Mean ± SD
Bright red, soft and sticky 9 9.6 ± 0.7
Freshness, good smell 9 9.6 ± 0.5
Cleanness 9 9.1 ± 0.8
Trust on seller 9 9 ± 1.1
Considered as safe meat 9 8.9 ± 0.9
Good storage 9 8.6 ± 1.8
Nutritional value 9 8.2 ± 2.0
Pork inspection document 9 8 ± 1.7
Accessibility 9 7.4 ± 1.7
Price 9 6.6 ± 1.1

51. 519/10/2013
* In-depth interview in Pork consumers
(2) Perception on low quality pork: sick or dead pigs, strange color,
smell badly or look wet.
(3) Knowledge on zoonoses: Mentioned at least one zoonotic disease:
such as cysticercosis, leptospirosis, anthrax, streptococcus suis
or diarrhea in pig.
(4) Observed human illness related pig or pork: no cases of illness or
diarrhea were observed in the recent 12 months.

52. 529/10/2013
* In-depth interview Public health staffs
(1) Responsibilities related to food safety, zoonoses: Responsibilities
were on “cooked food”; apply the regulation, observe, training,
guide on food safety and hygienic practice.
(2) Collaboration on food safety, zoonoses management:
• Reporting and updating within sector or district authorities and
upper level
• Collaboration with with other sectors: was better and uniformed,
still need for further strengthening

53. 539/10/2013
* In-depth interview Veterinary staffs
(1) The gap in the inspection: Vets and Public health sector: Raw meat
and cooked food.
• Inspection duties in big or medium slaughterhouses, not frequent
in small/private
(2) Collaboration on food safety, zoonoses management:
• Collaboration_A task force team: Public health, commercial, trade
management, veterinary, environment, police, etc…
• Task force team: situation or “problem base” or “Food safety action
month”
• Collaboration among professional sectors: more effective, still
needs to improve, action plan, good mechanism.

54. 549/10/2013

55. 55
Salmonella prevalence in pig slaughterhouse
9/10/2013
* On pig carcasses (34.9%)
Lower than in other studies:
• 48.9% (Thai, 2007) - Vietnam
• 95.7% (Le Bas, 2006) - Vietnam
• 55.5% (Sanguankiat et al., 2010)- Chiang Mai, Thailand
• 36.7% (Sithigon, 2011) - Northestern Thailand
Higher than in other studies:
• 33.2% (Fries, 2006)- Northern Thailand
• 11.7% (Algino et al., 2009)- USA
• 11.2% (Korsak et al., 2003) Belgium
• 8.3% (EFSA, 2008) - in the EU- State members
* Worker hand (50%): 10.7% Khon Kean-Thailand (Sithigon. D, 2011)
* Cutting board (33.3%): 47.4% Hue–Vietnam (Takeshi et al., 2009)

56. 569/10/2013
* On Pork (42.9%)
Lower than in other studies:
• 69.9% (Phan et al., 2005) in Mekong Delta, Southern Vietnam
• 65% (Angkititrakul, 2005) in northeast Thailand
Higher than in other studies:
• 32.8% (Takeshi et al., 2009) in Hue - Vietnam
• 39.6% (Thai et al., 2012) in Northern Vietnam
• 34.5% in retail pork (Sanguankiat, 2010) Northern Thailand
• 0.3% to 4.3%. (Delhalle et al., 2009) in Belgium
* Cutting board (33.3%): 28.6% Hue–Vietnam (Takeshi et al., 2009)
Salmonella prevalence in pork market

57. 57
Salmonella number in pig slaughterhouse
9/10/2013
* On pig carcasses (< 0.075 MPN/cm2 and <0.3 MPN/g)
Within a range of <0.03–0.36 MPN/g
Ireland (Prendergast, 2008)
From: -3.40 ± 2.04 log CFU/cm2 carcass
Belgium (2009) (Delhalle et al., 2009)
* Cutting board (< 1.2 MPN/cm2):
Conveyor and table swabs ranging from <0.03–1.1 MPN/cm2
Ireland (Prendergast, 2008)
The low numbers of Salmonella cells were typically found in
food, feed and environment samples (Boughton, 2004)

58. 58
Salmonella number in pork market
9/10/2013
* On pork (< 0.3 – 15 MPN/g)
Lower range than:
 19 MPN/g in pork sausages
 0.03 to >110 MPN/g, with a mean value of 21.16 MPN/g
Italy (Bonardi et al., 2008)
Higher range than:
 Below 10 MPN/g, Germany (Sinell et al., 1990)
 Between <0.03 - 2.10 MPN/g, Ireland (Prendergast, 2009)
 From: -2.64 ± 1.76 log CFU/g, Belgium (Delhalle et al., 2009)

59.  Transport and lairage: important risk factors (Hurd, 2002)
 Characteristics of farms/herds is one of consideration as high-
risk herds (Fosse, 2008)
 Floor as an important source of pathogens including Salmonella
(Hald, 1999)
 Evisceration has been described in Europe as the major cause
of carcass contamination (Berends et al., 1997)
Risk factors of Salmonella contamination in
slaughterhouse
599/10/2013
Not found significant differences among potential risk
factors in slaughterhouses

60.  A direct association between Salmonella contamination of
pork cuts and equipment or/and surfaces (Prendergast et al.,
2008)
 The most important parameter with regard to contamination
were handling, general hygiene, time and temperature at
each stage (Wong et al., 2002)
 Hygiene performance, particularly at retail, had a significant
impact on the occurrence of Salmonella (Hansen, et al., 2010)
Risk factors of Salmonella contamination in marrket
609/10/2013
Wood table surface, using bucket water, cutting on table
surface and selling both retail and wholesale

61. 61
Salmonella serotypes prevalence in slaughterhouse
9/10/2013
8 serotypes: S. Typhimurium and S. Derby (19.4%), S. Rissen
(16.1%), S. London, S. Meleagridis (12,9%); S. Give, S. Anatum, S.
Weltevreden (3.2-9.7%)
 S. Typhimurium (20.7%), S. Weltevreden, (15.3%), S. Derby (11.7%)
and S. Rissen (11.7%) (Vo, 2006) - Vietnam
 S. Derby (41%) and S. Typhimurium (29%) (van Hoek et al., 2012)-
Netherlands
 S. Typhimurium and S. London were the most common of the 24
serotypes (Schmidt et al., 2012) – US

62. 62
Salmonella serotypes prevalence in market
9/10/2013
9 serotypes: S. Derby (19.4%), S. Anatum and S. Meleagridis
(16.7%), S. London and S. Rissen (13.9%), S. Bovismorbificans, S.
Give, S. Stanley and S. Weltevreden (2.8 – 5.6%)
 S. Anatum (19.8%), S. Derby (15.9%), S. Typhimurium (13.5%),
except S. Infantis (13.5%), S. Reading (7.9%), S. Newport (6.3%)
(Thai et al., 2012) – Northern Vietnam
 S. Derby, S. Weltevreden, and S. London in pork, S. Bovismorbificans
in retail meat (Phan et al., 2005)- South Vietnam
 S. Rissen (61.5%), S. Stanley and S. Lexington (11.5%).
(Angkititrakul et al., 2005)- Thailand
 S. Derby, S. Anatum, S. Typhimurium, and S. Schwarzengrund (Chen
et al., 2006)- Taiwan

63. 63
Salmonella serotypes prevalence in market
9/10/2013
9 serotypes: S. Derby (19.4%), S. Anatum and S. Meleagridis
(16.7%), S. London and S. Rissen (13.9%), S. Bovismorbificans, S.
Give, S. Stanley and S. Weltevreden (2.8 – 5.6%)
• S. Typhimurium is a serotype predominantly and followed by S.
Enteritidis and S. Weltevreden isolated from humans in Vietnam (Vo et
al., 2006)
• PFGE: S. Derby was detected in 19% of strains from humans, 52%
from food (include pork products), and 62% from swine in Spain
(Valdezate et al., 2005)

64. 64
Perception related to food safety with the potential
risks in practices
9/10/2013
• Applied an integrated approach: Quantitative (Salmonella
contamination) and qualitative (FGD, IDI) – hasn’t been applied before
• Improvement of the practices could considerably reduce the carcass
contamination.
- Using gloves (not used) => found hight prevalence on hands
- Using cloth to wipe => habor of Salmonella !?
- “Trained by doing”=> standard information and training

65. 65
Perception related to food safety with the potential
risks in practices
9/10/2013
• Using wooden tables because of their perception that meat looks
longer fresh => still prefer to use it
This gap is currently addressed by the Livestock Competitiveness
and Food Safety Project (LIFSAP) of government.
=> The LIFSAP project plans also to upgrade facilities in selected
open fresh food markets and slaughterhouse. (ILRI, 2010b).
- Enhance facilties and good hygiene practice in slaughterhouse
- Investment replacing wooden tables by stainless steel ones
- Providing pork retailers with hangers to hang carcass, etc.

66. 66
Perception related to food safety with the potential
risks in practices
9/10/2013
• Important selection criteria for purchasing pork: fresh pork (Lapar et
al., 2009)
• Price has lowest important, but a study in Germany, price was
important (Rohr et al., 2005)
• Our finding related to zoonoses revealed that almost all actors had little
knowledge or some misperception on zoonoses in agrement with
ongoing study in Vietnam (Hung et al., 2012).

67. 679/10/2013

68. Prevalence of Salmonella:
 36.9% in slaughterhouse, 34.9% on carcass
 41.4% in pork markets, 42.9% in pork
The number of Salmonella:
 < 0.075 MPN/cm2 on carcass
 < 0.3 to 15 MPN/g on pork
Potential risk factors of Salmonella contamination:
 In pig slaughterhouses: not found
 In pork in market: wood table surface, bucket water, cutting
on table surface, selling both retail and wholesale.
68
Conclusion
9/10/2013

69. The most frequent Salmonella serotypes:
 In slaughterhouse:
S. Typhimurium, S. Derby (19.4%),
S. Rissen (16.1%) , S. London, S. Meleagridis, S
(12.1%). Weltevreden, S. Give and S. Anatum
In market:
S. Derby (19.4%), S. Anatum, S. Meleagridis (16.7%),
S. Rissen, S. London (13. 9%),
S. Bovismorbificans, S. Give, S. Weltevreden.
69
Conclusion
9/10/2013

70.  The survey on perception and hygienic practice related to
food safety of relevant groups and stakeholders:
 Provided basic information and contribute a better understanding
of their practice.
 Require of standards and targeted training for slaughter workers
and pork sellers.
 Help to better engagement in management on groups, actors in
pork production chain.
70
Conclusion
9/10/2013

71. 719/10/2013
Acknowledgement
 Veterinary Public Health Center for Asia Pacific (VPHCAP) - CMU
and Freie Universität Berlin
 USAID (the EPT/RESPOND program), Hanoi School of Public
Health (HSPH), CENPHER (HSPH), Eco Health One Health
Resource Center, CMU and International Livestock Research
Institute (ILRI, EcoZD project)
 Dr. Fred Unger (ILRI) and Assoc. Prof. PhD. Nguyen Thanh Huong
(HSPH)
 Slaughterhouse owners, workers, pork sellers and local veterinary
staffs in Hung Yen
 Department of Veterinary Hygiene-NIVR (Vietnam)

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9/10/2013