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Microbiological Risk

Assessment by JEMRA

Hajime TOYOFUKU, DVM., PhD

Professor,

Joint Faculty of Veterinary Medicine

Yamaguchi University, Japan

FAO Workshop

Bangkok, Jan 2017

Table of contents

History of JEMRA

MRA framework

Probabilistic approach

Examples of MRA performed by JEMRA

Listeria monocytogenes

Cronobacter sakazakii

Topic 4 – Joint FAO/WHO Expert Meetings on Microbiological Risk Assessment:

Introducing JEMRA

Risk analysis – developments

at international level (1)

FAO/WHO

Conference

recommendation to

Codex re use of

science

1991 1995

FAO/WHO

Expert Cons.

on RA

FAO/WHO

Expert Cons.

on MRA

FAO/WHO

Expert Cons.

on RM

FAO/WHO

Expert Cons.

on RC

1997 1998 20021999 2003

WTO SPS

Agreement

Codex activities

Adoption of statements of principles re use

of science and food safety risk assessment

and risk analysis terminology and guidelines

2000

FAO/WHO

Expert Cons.

on MRA and

RM (JEMRA)

Topic 4 – Joint FAO/WHO Expert Meetings on Microbiological Risk Assessment:

Introducing JEMRA

Risk analysis – developments

at international level (2)

JEMRA

FAO/WHO

Expert Cons.

on MRA

Codex activities

Adoption of Codex

Principles and Guidelines

for MRA

Codex request

FAO/WHO

to establish

an advisory body

on microbial

hazards in foods

CCFH request

advice on

specific

pathogen

-commodity

pairs

200019991997 2010

FAO/WHO

Expert Cons.

on MRA and

RM

FAO/WHO

Web-based

MRA decision

tools

20072006

Table of contents

History of JEMRA

MRA framework





Low moisture food

Food-borne parasite

H.Toyofuku

Risk assessment components

H.Toyofuku 24年度食品衛生危機管理21 Jan, 2013

Differences between microbiological and chemical

hazards regarding risk assessment methodologyMicrobiological hazards Chemical hazards

・Hazards may be introduced any

points along with food chain from

primary production to consumption.

・Hazards may be introduced at a

specific point in the food chain.(e.g.

Acrylamide )

・Concentrations and/or prevalence of

hazards change significantly along with

food chain.

・After the introduction, hazard level in

food usually stay the same.

・Health risk is usually acute, caused

by a single exposure (through

consumption of one meal.)

・Health risk is usually chronic, caused

by continuous exposures. even though

some are acute.

・Host reaction against different

hazard levels may be significantly

different.

・Characteristics of toxic effects are

similar among individuals, but

sensitivity may differ among

individuals.

Table of contents

History of JEMRA

MRA framework





Challenges

Complexity vs. Resources - Often the key factor in

choosing an approach

H.Toyofuku Topic 3 - Lecture 2 - Microbiological Risk Assessment:

methodology

Point estimates VS. Probability distribution

Growth of bacteria

H.Toyofuku

Probabilistic risk assessment • In put: using probability distributions as inputs, and calculate

risk

• Output; probability distribution

• Characterise the likelihood of events

• Variability and uncertainty are reflected in the risk estimate.

• Variations existing in the real world are recognized.

Monte-Carlo simulations

• Sampling from probability distributions which describe variation and uncertainty

• Distribution based on real data or assumptions

• to combine a large number of times (iterations)


methodology

Probabilistic estimates


methodology

Average

Bac. con

= log CFU/g

Bac. growth

= log CFU/g

Bac. inactivation

= log CFU/g

Con level = log CFU/g

Consumption = g

Exposure = log or

CFU/serving

Worst case (95%)

Bac. Con.

= log CFU/g

Bac. growth

= log CFU/g

Bac. inactivation

= log CFU/g

Con. level = log CFU/g

Consumption = g

Exposures = log or

CFU/serving

[Initial concentration + growth – inactivation] x consumption

Point Estimates


methodology

Average

Bac. Con = 2.0 log CFU/g

Bac. Growth = 1.5 log CFU/g

Bac. inactivation

= 3.67 log CFU/g

Con level = -0.17 log CFU/g

Consumption = 53 g

Exposure = 1.7 log or 35

CFU/serving

Worst case (95%)

Bac. Con. = 3 log CFU/g

Bac. Growth = 1.8 log CFU/g

Bac. Inactivation = 2.8 log CFU/g

Con. level = 2.0 log CFU/g

Consumption = 85 g

Exposures = 4 log or 8500

CFU/serving

[Initial concentration + growth – inactivation] x consumption

Point Estimates


methodology

0.0000

0.0200

0.0400

0.0600

0.0800

0.1000

0.1200

-28 -26 -24 -22 -20 -18 -16 -14 -12 -10 -8 -6 -4 -2 0

Log Probability of Illness

Safe level?

Range of possible outcomes

Likelihood of various outcomes

Risk estimate with a distribution

H.Toyofuku

Four components of risk assessment

• What is hazards?

• What information we

have with regards to

hazards?

（microbial &

epidemiological data）• Evidence that the

hazard causes

adverse health

effects

Hazard Identification

Exposure Assessment

Hazard Characterization

[Dose-Response]

Risk Characterization

H.Toyofuku


• How likely the food

is contaminated ?

• How much the level

of the pathogen?

• How much and how

often the food is

consumed?

• The level and

prevalence of the

hazard at the time

of consumption


Exposure Assessment


[Dose-Response]


H.Toyofuku


• How likely people

get sick after the

exposure to the

contamination food

at the given dose?

• Establish Dose

Response

• Identify high risk

populations


Exposure Assessment


[Dose-Response]


H.Toyofuku

Questions from risk managers

• How likely the adverse health

effects?

• How serious the adverse health

effects?

• Who are high risk population?

• Which factors influenc the

results?

Advice to find effective

interventions

Risk Assessment components


Exposure Assessment



Table of contents

History of JEMRA

MRA framework





Question posed by Codex to

JEMRA １Estimate the risk of serous illness from L.

monocytogenes in food when the number of

organisms range from:

- Absence in 25 g（not existence）

to

- 1000 cfu per gram or ml

Or does not exceed certain levels at the time of

consumption

Estimated annual number of listeriosis

FAO/WHO Risk assessment of Listeria monocytogenes in ready-to-eat foods

The effect of the proportion of

defective serving

FAO/WHO Risk assessment of Listeria monocytogenes in ready-to-eat foods

Importance of compliance with

established criteria

The rate of defective servings is a more

significant risk factor than the numeric

value of the criterion within the range

that CCFH asked the risk assessment

team to consider

This issue was considered by the

working group and the Plenary of

CCFH

MC of Listeria monocytogenes

Cronobacter sakazakii in

powdered infant formula• Cronobacter species has recently emerged as a pathogen of infants.

• All infants (<12 months of age) at particular risk for Cronobacter spp infections.

Among this group, those at greatest risk are neonates (<28 days), particularly

pre-term, low-birthweight (<2500 g), and immunocompromised infants, and those

less than 2 months of age

• Reported fatality rates of Cronobacter spps infections in infants vary considerably

with rates as high as 50 percent reported in at least one outbreak

• The primary manifestations of Cronobacter spp infection in infants, i.e.,

meningitis and bacteremia, tend to vary with age.

• PIF is not a sterilized product.

• C.sakazakii survive in dry environments for prolonged periods of time

• Source: 1) through the ingredients added in dry mixing operations during the

manufacturing of PIF, 2) through contamination of the formula from the processing

environment in the steps during or following the drying, 3) through contamination of

the PIF after the package is opened, and 4) through contamination during or after

reconstitution by the caregiver prior to feeding.

• After reconstitution, C.sakazakii grow in PIF

• Risk could be reduced by using hot water (over ７０℃) for the reconstitution

Thank you for your attention.

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