July 25,2002 1

Microbiology Risk Assessment in Microbiology Risk Assessment in China:China:

Current Situation & ChallengesCurrent Situation & Challenges

Xiumei Liu

Institute of Nutrition and Food Safety

China CDC

July 25,2002 2

Risk AnalysisRisk Analysis

Risk assessment Risk management

Risk communication

July 25,2002 3

RA A scientifically based process

RM The process of weighing policy alternatives,

distinct from risk assessment

July 25,2002 4

MRA in the Word

Foodborne bacteria Risk Assessment FAO/WHO （ JEMRA ） Risk Management Codex （ CCFH ）

Mycotoxins, metabolites of fungi Risk Assessment FAO/WHO （ JECFA ） Risk Management Codex （ CCFAC ）

July 25,2002 5

China Activities in MRA

CCFH Since 32nd 1999

JEMRA Since 2000, Food hazard, EA, QMRA

CCFAC Over 10 years, 32nd 2000 in Beijing

JECFA Expert and data contribution

(AF, Fumonisin, DSP)

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Why MRA is needed in China ？

WTO CODEX / GB FOOD INDUSTRY

FOOD SAFETY CONTROL Government Consumers

HEALTH PROTECTION Life quality knowledge

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Risk AssessmentRisk Assessment

Hazard Identification

Hazard Characterization

Exposure Assessment

Risk Characterization

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Hazards in FoodHazards in Food

Foodborne bacteria

Fungi and mycotoxins

Viruses and parasites

Toxic plants and animals

Potential environmental toxicants

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Foodborne bacteria in China

Pathogens Mortality (%)

Salmonella 0.1 Bacillus cereus 0.037 Burkholderia cocovenenans 40 Proteus 0.03 Staphylococcus aureus 0.045 Clostridium botulinum 7.3 Escherichia coli 0.1 Vibrio parahaemolyticus 0.01

(1990-1996)

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Case 1Case 1 BA Food Poisoning Control

1933 Indonesia: Fermented coconut food poisoning1960 Pseudomonas cocovenenans Bongkrekic acid

1950’s China: Unknown causes fermented corn flour poisoning

1979 Flavobacterium farinofermentans nov. sp

1984 China: Deteriorated tremella poisoning,

1987 P. cocovenenans subsp. farinofermentans1995 Burkholderia cocovenenans (B. gladiali)

July 25,2002 11

Bongkrekic acid Food Poisoning Caused by Various Food in China

Food Provinces Outbreaks Patients Fatal Mortality cases (%)_______________________________________________________________Cereal products 12 78 499 238 62.12

Deteriorated tremella 5 22 148 54 36.49

Potato product 3 3 20 9 45.00 Total 16 103 667 301 45.13_______________________________________________________________

(1985-1994)

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Hazard identification:Bongkrekic acid, BA

Molecular formula C28H38O7

LD50

3.16mg/kg

Target Organs

LiverBrainKidney

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Studies on the last 15 years         Identification and examination of the foodnorne pathogen

         Identification analysis and detoxication of BA         Diagnosis, monitor and prevention of food poisoning

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Risk Manegement in China

GB/T 4789.29-94 Examination of P. cocovenenans subsp. Farinofermentans

GB 11675-89 Hygienic Standard of Tremella (BA Detection method)

GB WT/12-96 Diagnostic Criteria and Principle of Management for P.

Cocovenenans subsp. farinofermentans Food Poisoning

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BA poisoning control

Outbreaks of BA reduced about 80%

in 1990’s.

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Prevalence in fly feces

Prevalence

Fig Distribution for E.coli prevalence in fly feces

——Beta(235,1988-235+1)

Mean: 11.9%

5th-95th: 10.7%-13.1%

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Number of houseflies

Month Average flies density（ no. of flies/cage·day ）

Mar 21

Apr 63 May 125 June 221 July 314 Aug 341 Sep 257

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No. of ingested bacteria

0

0. 05

0. 1

0. 15

0. 2

0. 25

0. 3

0. 35

0 1000 2000 3000Number of i ngested bacteri a

Frequency

Mean: 310 cfu/meal

5th-95th:

23 ～ 875cfu/meal

July 25,2002 19

Exposure probability

0

0. 02

0. 04

0. 06

0. 08

0. 1

0. 12

0. 14

0. 16

0. 54 0. 59 0. 64 0. 69 0. 74Exposure probabi l i ty

Frequency

Mean: 63.5%

5th-95th: 59.5% ～ 67.4%

July 25,2002 20

Natural toxicants --Actual and potential effects in humans

Acute effects liver illness, poisoning, death

Aflatoxin, DON, 3-NPA, Ergot Microcystin, Saxitoxins, Domoic acid, Solanine

Chronic effects Carcinogenic, genotoxic & endemic illness

Aflatoxins, Fumonisins, Deoxynivalenol, Zearalenone, Ochratoxin A, Patulin, T-2 toxin, Moniliformine, Sterigmatocystin

Microcystin, Domoic acid, Cyanogenic glycosides

July 25,2002 21

Example: Aflatoxin B1

Animal toxicity data showed: it could cause primary liver cancer in most species studied

Epidemiological studies found an association between consumption of food contaminated with aflatoxin B1 and liver cancer

Is a genotoxic carcinogen

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Quantitative risk assessment at 49th JECFA Meeting

HBsAg ( ＋ ) :0.3 liver

cancer/year/100,000/ ng AF/ kg bw/day

HBsAg ( － ) :0.01 liver cancer /year /100,000 / ng AF/kg bw/day

July 25,2002 23

HBsAg( ＋ ) 1%; European Cont. level & Dietary Pattern

AFB1 intake Risk (ng/day)

(Cancer/year/100,000)

AFB1 limit 20 µg/kg 19 0.0041 (0.0006-0.01)

AFB1 limit 10 µg/kg 18 0.0039 (0.0006-0.01)

2 cancers/year/billion

July 25,2002 24

China cont. level and far east dietary pattern

AFB1 intake Risk (ng/day)

(Cancer/year/100,000)

AF limit 20 µg/kg 125 0.17 (0.03-0.3)AF limit 10 µg/kg 103 0.14 (0.02-0.3)

300 cancers/year/billion

*The mortality of liver cancer was 20/100,000 in the period of 1990-1992. (20.03/100,000)

July 25,2002 25

Case 2 Case 2 The Control of the Deteriorated The Control of the Deteriorated Sugarcane Food Poisoning in ChinaSugarcane Food Poisoning in China

Fresh sugarcane grown in southern area of China

Usually shipped to northern parts of

China, stored and sold through the winter season

Contaminated sugarcane can cause fatal food poisoning when sold in the next spring

July 25,2002 26

Sugarcane poisoningSugarcane poisoning

The first outbreak of sugarcane poisoning with unknown causes occurred in Henan Province in 1972

From 1972 to 1989: No. of outbreak: 217 No. of cases: 884 No. of deaths: 88 Average fatality: 10%

Identified as a priority to assess and control

July 25,2002 27

Characteristics of 34 MSP Cases

 

Age: 3 to 27 years old

Incubation period: 10 minutes to 8 hoursManifestations: Vomiting

DystoniaStare on one sideConvulsionCarpopedal spasm ComaElectroencephalogram

Sequelae

July 25,2002 28

Etiology and risk assessmentEtiology and risk assessment

Etiology: the Chinese Academy of Preventive Medicine studied on the etiology of this specific food poisoning since 1984 and found: Arthrinium spp. was the pathogenic fungus; 3-nitropropionic acid (3-NPA) produced by A. spp.

was proved to be the causative compound

Assessment was made according to case-based studies, epidemiological and laboratory studies

July 25,2002 29

Decision making and management activities

Based on discovery and assessment, MOH promulgated:

Diagnostic criteria and principles for the management of deteriorated sugarcane poisoning (WS/T10-1996);

Methods for the isolation and identification of Arthrinium strains and analyzing 3-nitropropionic acid (GB47689.16)

At the same time, MOH issued a notification on the prevention and control of DSP to all provinces of China

A national health campaign for prevention and control of the poisoning was launched

July 25,2002 30

Prevention and control measuresPrevention and control measures

The main measures adopted by local health inspectors:

Fresh sugarcane shipped to northern China should not be stored for more than 3 weeks

The deteriorated sugarcane with unpleasant smell and mold growing should not be sold in market

When poisoning outbreak occurred, the suspected left-over sugarcane should be immediately sealed and destroyed

During the outbreak, food inspectors and clinical doctors should work closely to identify and treat patients

July 25,2002 31

Good resultsGood results

As a result of these efforts, sugarcane poisoning has been satisfactory controlled

No typical cases were reported in China in the last 10 years!

July 25,2002 32

Challenges: Areas for Strengthening

Knowledge Team （ National level ） Practice （ Data, Modeling ）

Food consumption / dietary intake Effects of processing

QMRA   (Quantitative method) Analytical methods Sampling protocols

July 25,2002 33

FAO/WHO Activates in China

Workshop on Microbiological Risk Assessment Sponsored by FAO/ ILSI /WHO/ MOH May 10-11, 2002 Beijing

Quantitative Microbiological Risk Assessment Training Course (David Vose) Sponsored by WHO/INFS May 13-24, 2002 Beijing