f. kasuga 1 st int conf mra archiving of food samples from restaurants and caterers fumiko kasuga...
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F. Kasuga1st Int Conf MRA
Archiving of food samples from restaurants and caterers
Fumiko Kasuga
National Institute of Health Sciences, Japan
(National Institute of Infectious Diseases)
F. Kasuga1st Int Conf MRA
An example of data collection for Hazard Characterization
Analysis of outbreak data in Japan
F. Kasuga1st Int Conf MRA
Hazard Characterization describes,
• Pathogen concerned– serotypes, virulence, toxins, etc
• Population involved, susceptible, at risk
• Vehicle foods – contaminated, protect pathogens against stomach acid,
inactivate pathogens or inhibit proliferation
• Dose response: how likely to get ill?
F. Kasuga1st Int Conf MRA
Data for dose-response
• Pathogen dose ingested– concentration in food – food amount taken
• Attack rate (or P(infection), P(death), etc.)– population exposed– infected, ill, dead, etc.
F. Kasuga1st Int Conf MRA
Data source for dose-response
virulence dose range size components amount
Human feeding data weak to mild controlled healthy adults controlled monotonous controlled
Animal experiment data rather strong controlled difficult to convert controlled monotonous controlled
Outbreak data varioususually difficult toknow
from babies to elderlyusually difficult toknow
diverseusually difficult toknow
FoodPathogenData source
Target population
* Outbreak data has limitations, needs assumptions when used, but reflects real-world events.
F. Kasuga1st Int Conf MRA
What we have experienced…
F. Kasuga1st Int Conf MRA
MRA 00/03
Joint FAO/WHO Expert Consultation on Risk Assessment of Microbiological Hazards in Foods
FAO Headquarters, Rome, Italy
17 - 21 July 2000
- Preliminary Report - Hazard Identification and Hazard
Characterization of Salmonella in broilers and eggs
Food and Agriculture Organizationof the United Nations
World Health Organization
F. Kasuga1st Int Conf MRA
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Log Dose
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11 12
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30 31
32 34
Otbrk-BP
Beta-Poisson model for Salmonella spp. derived using outbreak data
F. Kasuga1st Int Conf MRA
Why was it possible?
F. Kasuga1st Int Conf MRA
Japanese Directive "Controlmeasures against foodborne outbreaks"
issued in march 1997 by Director General of Environmental Sanitation Bureau of the Japanese Ministry of Health and Welfare
large scale cooking facilities more than 750 meals per day more than 300 dishes of a single menu at a time
food saving50 gram aliquots of each raw food material and cooked dish more than 2 weeks, lower than -20 C
F. Kasuga1st Int Conf MRA
Original purpose of food-storing system was to improve identification of vehicle food by microbiological examination.
F. Kasuga1st Int Conf MRA
Food-storing system
improvement of causative food identification
Quantitative data (concentration in food)
co-operation with laboratories
Complete data set for Hazard CharacterizationCoordination
Kitchen owners
Health centers
Prefectural laboratories
•cost supply
•epidemiological investigation
•facility and technique
capacity
• cost supply
•Exposed•Ill•Food amount taken
F. Kasuga1st Int Conf MRA
How do we combine those data?
F. Kasuga1st Int Conf MRA
Outbreak reports• Format, elements vary
– Essential elements are required to be included.
• Rapid reports by FAX or e-mails– Changeable, not confirmed
• Detail reports– Several months later
• Administrative reports• in Japanese
F. Kasuga1st Int Conf MRA
Outbreaks for which detail reports to MHLW are required (1)
• With more than 50 patients
• With less than 50 patients and with following characteristics
– Death involved
– Caused by imported food
– Occurred in more than two prefectures by single source
F. Kasuga1st Int Conf MRA
Outbreaks for which detail reports to MHLW are required (2)
• With less than 50 patients and with following characteristics (continued)– Unique epidemiology, or complicated investigation and
actions needed– Caused by the following pathogens
• Yersinia enterocolitica O8• Campylobacter jejuni / coli• Salmonella Enteritidis• Enterohemorrhagic E. coli• Clostridium botulinum
F. Kasuga1st Int Conf MRA
Analysis of outbreak data (1989 – 1998) with Salmonella concentrations in
implicated foods:
In total 39 outbreak reports were collected, and they were divided into 5
categories upon settings.
F. Kasuga1st Int Conf MRA
Outbreaks occurred at schools
• Ages of pupils in an elementary school are 6 to 12.
• Most schools serve the same lunch menu to all of their pupils on a single day.
• All the pupils in the school are reasonably considered to be the exposed population in those outbreaks.
• The exposed population to the contaminated food is usually very large
F. Kasuga1st Int Conf MRA
Case Vehicle Bacterial Food amount Dose ingested Exposed Death Illness Attack rate
No. concentration intake (g) (CFU) （％）
1 SE*1
(PT*2
1) peanuts dressing <100*3
80 <8000 2267 0 418 18.44
2 SE peanuts dressing 4.3*4
80*6
344 1320 0 179 13.56
3 SE (PT 22)beef and bean sproutswith sesame dressing 40
*522 880 10552 0 967 9.16
4 SE (PT 1)spinach with peanutsdressing 1.4
*435 49 5320 0 644 12.11
Salmonella serotype(phage type)
Outbreaks occurred at schools
*1 SE: Salmonella Enteritidis
*2 PT: phage type
*3 direct plate count, detection limit 100 CFU/g
*4 MPN/g
*5 direct plate count, CFU/g
*6 food amount undefined in original report and assumed to be as same as Case No. 1
F. Kasuga1st Int Conf MRA
Outbreaks occurred at schoolsSymptoms
*7
D S Fe V N C Fa H O
309 383 148 28 125 75 212 154 frozen for 9 days
10 g sample was negative for SE,when 0.1 ml of 10 times dilutedsample was plated on SS medium.SE was detected from 25 g samplethat was incubated in EEM.
137 102 75 5 12 27 51 52 88 unknown3 tube-MPN method using SBGmedium, confirmed on DHL..
851 839 594 151 286 380 479 541 refrigerated0.1 ml of 10 times diluted sample of10 g plated on MLCB.
463 584 314 58 94 55 88 173 frozen for 7 days
10 g sample diluted to 1:10, then 5tube-MPN method using EEM,SBG, SS, and DHL..
Food conditionprior to testing
Reported laboratory test
methods*8
*7 abbreviation for symptoms: D; diarrhea, S; stomachache, Fe; fever, V; vomitting, N; nausea, C; chill, Fa; fatigue, H; headache, O; others
*8 abbreviation for culture media: SBG; Selenite Brilliant Green, DHL; Deoxycholate Hydrogen Sulfide Lactose Agar, MLCB; Mannitol Lysine Crystal Violet BrilliantGreen Agar, EEM; Enterobacteriaceae -Enrichment Mannitol, SS; Salmonella Shigella Agar
F. Kasuga1st Int Conf MRA
Outbreaks occurred at daycare centers
• The age of children is less than 1 up to 6 years old.
• In general, the size of daycare population is smaller than that of schools and each daycare has its own kitchen in most places.
• Therefore the exposed populations were smaller than those of school cases.
• Attack rates were higher than those in school outbreaks, which might reflect the susceptibility of the population.
F. Kasuga1st Int Conf MRA
Outbreaks occurred at daycare centers
Case Vehicle Bacterial Food amount Dose ingested Exposed Death Illness Attack rate
No. concentration intake (g) (CFU) （％）
5 SE macaroni salad 1100*2
40*5
44000 152 0 52 34.2116
*70 3
*718.75
*7
117*8
0 50*8
42.74*8
7 SE egg salad 0.78*3
40 31.2 156 0 42 26.92
8 SE (PT 1) scrambled eggs 130000*3,4
40 5200000 74 0 33 44.59
SE
Salmonella serotype
(phage type)*1
6 chicken and eggs on rice 27*2, 6
150*6
4050
*1 abbreviation used as same as Table 1
*2 direct plate count, CFU/g
*3 MPN/g
*4 bacterial concentration in stored raw egg mixture
*5 food amount undefined in original report and assumed to be as same as Case No. 7
*6 mean of reported values
*7 adult nurses
*8 children under 6
F. Kasuga1st Int Conf MRA
• Hospital inpatients are generally considered to be more susceptible to pathogens than the healthy, normal population.
• The attack rates in collected outbreaks, however, were not very high.– the influence of concurrent medications
including antibiotics??
Outbreaks occurred at hospitals
F. Kasuga1st Int Conf MRA
Outbreaks occurred at hospitalsCase Vehicle Bacterial Food amount Dose ingested Exposed Death Illness Attack rate
No. concentration intake (g) (CFU) （％）
9 SE (PT 1) tartar sauce <100*2
36 <3600 126 0 36 28.57
10 SE natto with raw eggs 1200000*3
50 60000000 191 0 45 23.56
11 SE (PT 4) grated yam diluted with soup 2400*4
60 144000 343 0 75 21.87
33 S.typhimurium grated yam diluted with soup 2300*4
60*5
138000 99 0 40 40.40
34 S.typhimuriumgrated yam diluted with soup(with quail eggs) 40000
*360
*52400000 79 0 39 49.37
Salmonella serotype
(phage type)*1
*1 abbreviation used as same as Table 1
*2 direct plate count, detection limit 100 CFU/g
*3 direct plate count, CFU/g
*4 MPN/g
*5 food amount undefined in original report and assumed to be as same as Case No. 11
F. Kasuga1st Int Conf MRA
• Kitchens vary in size, the scale of outbreaks also differs.
• Amounts of ingested food were not always specified in the original reports, and assumptions were often made to estimate ingested dose of pathogens.
• The food storage conditions were also different among the outbreaks.
Outbreaks occurred at restaurants, hotels, caterers, and other business
kitchens(20 outbreaks)
F. Kasuga1st Int Conf MRA
Outbreaks caused by confectionaries(6 outbreaks)
• Number of exposed people varies much in this group, from small outbreak with 5 cases to very large outbreak with more than one thousand.
F. Kasuga1st Int Conf MRA
Comparison of dose-response from outbreaks where food samples were
kept frozen or not- effect of freezing food system
F. Kasuga1st Int Conf MRA
Relationship between the ingested bacterial dose and the attack rate
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F. Kasuga1st Int Conf MRA
Outbreaks where food portions were stored frozenDose-response relationship in outbreaks where foods were frozen
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F. Kasuga1st Int Conf MRA
Outbreaks where food portions were not frozen
Dose-response relationship in outbreaks where foods were not frozen
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F. Kasuga1st Int Conf MRA
Summary of my talk (1)Food-storing system• Might be a good example of co-operation of
management and assessment.• Existing measures helped data collection for risk
assessment.• Very useful for developing dose-response models.• Need to encourage local authorities to continue
enumeration of causative microbes.– May need additional mechanism, cost supply.
F. Kasuga1st Int Conf MRA
Summary of my talk (2)Outbreak reports• Not always comprehensive, improvement of
epidemiological investigation and report formatting needed.
• Case definition, recognition of foodborne outbreak is not systematically defined.– Underestimation of reported cases.
• Many outbreak reports are useful.• Translating to English under discussion.• Current summary to be available.
F. Kasuga1st Int Conf MRA
Thank you!Co-workers:Masamitsu Hirota1), Masamichi Wada2), Toshihiko Yunokawa3), Hajime Toyofuku4), Masaki Shibatsuji5), Hideshi Michino5), Toshiaki Kuwasaki5), Susumu Kumagai6), Shigeki Yamamoto1) 1) National Institute of Health Sciences2) Nagano Research Institute for Health and Pollution3) National Institute of Public Health4) Food Safety Programme, World Health Organization5) Ministry of Health, Labour and Welfare6) The University of Tokyo
Special advisors:Anna Lammerding, Aamir Fazil, Eric Ebel
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