食品のリスク評価－食中毒原因微生物、放射性物質－
Food Risk Assessment - Food Poisoning Causative Organisms, Radioactive
Nuclides in Foods
内閣府 食品安全委員会事務局 情報・緊急時対応課長・新本 英二

Eiji SHINMOTO, Director, Information and Emergency Response Division,
Cabinet Office Food Safety Commission of Japan (FSCJ)

Hello everybody. I am Eiji Shinmoto from the Cabinet

The FSCJ was established inside the Cabinet Office in

Office Food Safety Commission of Japan.

2003 to carry out risk assessment and control as partof an overall framework for food safety in Japan. Until

Today’s workshop is on the theme of food safety. Of thethat time, the Ministry of Health, Labour and Welfare

three factors mentioned by the chair earlier, I am going(MHLW) and the Ministry of Agriculture, Fisheries andto talk about food safety and in particular about risk

Food (MAFF) had conducted risk assessment and risk

assessment. The FSCJ conducts risk assessments based

control separately. But due to the occurrence of various

on scientific knowledge. As examples of our recent

problems relating to food safety a major readjustment

assessments, I will talk about a risk assessment for theto food safety administration was implemented. Thesemicroorganisms that cause food poisoning, which were

problems included the identification, for the first time

the subject of a previous talk. I will also talk about ain Japan, of BSE-infected animals and the distribution

risk assessment of radioactive materials which haveof unregistered agricultural chemicals. The FSCJ is an

been the focus of much debate regarding their control

organization established to carry out risk assessment

ever since the 2011 Fukushima Daiichi Nuclear Powerseparately from risk control but from a neutral, fair and

Plant disaster.

scientifically reliable standpoint.

When we speak of food risks, we could be referring to

As I say, risk control conducted for the regulationa variety of dangers that can affect food. For example,

and supervision of individual foods is handled bythere are biological factors such as food poisoning

the MHLW and the MAFF while the FSCJ conductscausative microorganisms, prions, and various chemical

the risk assessment. For instance, in the case of

substances. There are also physical risk factors, suchsetting a regulatory value for a specific food, theas the risk of choking when eating certain foods such

FSCJ scientifically assesses the risk in advance foras devil’s tongue. Radioactivity represents anotherthe specific hazard to be regulated. Based on thephysical risk factor. Dangers such as these exist withinassessment results and in addition to any scientific

the food itself and our task is to assess how great thebasis, the technological possibilities, cost-effectivenessrisk to health might be when people eat various foods.

and other factors are also considered as an integrated

In this context, the scale of the risk is calculated bywhole and the conclusions implemented using concrete

multiplying the probability of food poisoning occurring

control measures. That is risk control.

(when ingesting a causative agent) by the size of theagent’s effect. So even if the pathogen can produce

Under the present system for maintaining safety andmajor symptoms, if the probability of food poisoning

reassurance, which is termed risk assurance, risk

incidents is very small, the risk may be ignored or else

communication is very important. Risk communication

accepted. To clarify risk size scientifically is one of theis carried out by the assessment organization and

FSCJ’s major roles.

the control organization respectively. However, foodsafety cannot be realized by the administration alone.

206

りぶ・らぶ・あにまるず 神戸アニマルケア国際会議 2012

It can only be realized if all the various stakeholders the businesses, consumers and others – perform their

On receiving this inquiry, our Prion Expert Panel began

own respective roles properly. Accordingly, all theseits current deliberations. The initial panel session

related parties need to share the relevant information

was held in January and it was recently announced

on food safety requirements and communicate it sothat the second session would take place on Februarythat everybody understands what needs to be done.

27. Although I can’t say when the deliberations will

This is why an emphasis needs to be placed on risk

be completed, I want to assure you that fair andcommunication.

scientifically based deliberations about prions are
happening.

About eight years have passed since the FSCJ wasestablished. Over that time we have received requests

I will now introduce several risk assessment examples

to conduct well over 1,000 assessments, mainly from

related to food poisoning causative microorganisms.

control organizations, and we have actually completed

As Mr. Sakai and Prof. Morita introduced earlier, formore than 1,000 of them. In the livestock-raising

the risk assessment of food poisoning, the increase

field, we have conducted assessments of veterinary-or decrease of each kind of bacteria at the farmuse medical products and feed additives. We are also

stage, distribution stage and consumption stage

making a risk assessment of BSE prions in relation toare all major factors. Also, as Mr. Sakai stated, thetransmissions of variant Creutzfeldt-Jakob disease tofarm stage, slaughterhouse stage and distribution

humans via BSE.

stage are controlled by HACCP and the number ofbacteria present in food can be heavily influenced byToday, I am mainly intending to talk about foodthe quality of temperature control in the processing

poisoning and radiation but I will also talk more

and preparation stages. For risk management wegenerally about the BSE situation. The chair of today’s

take a scientific approach by analyzing the various

workshop, Prof. Yoshikawa, has also chaired the FSCJ’contributing factors at each stage.

s Prion Expert Panel. The FSCJ has carried out a varietyof BSE-related assessments. Based on their results,

As one example, I would like to introduce a 2009 case inJapan is now implementing control measures on US andwhich the FSCJ produced a summarized risk assessment

Canadian beef imports. We received a new inquiry fromfor Campylobacter bacteria within chicken meat. As

the MHLW about BSE in December 2011. In Japan BSE

Prof. Morita explained in his talk, Campylobacter live

testing is currently required on all cattle more than 21

in the intestinal tract of livestock including poultry.

months old. As for beef from the US and Canada, only

There is a considerable incidence of food poisoning

beef from animals below 20 months, for which importcaused by Campylobacter infected chicken meat. As

program guidelines have been followed, is eligible fora countermeasure, the simple sufficient heating ofimport into Japan. The MHLW’s present request to us

the chicken meat prior to serving can eliminate theis as follows. If the test month for these cattle were to

problem so there is little reason to worry about cross-change from 20 months old to 30 months old, howcontamination if such attention is paid. The FSCJ madewould this change the infection risk?

a risk assessment on the combination of chicken meat
and Campylobacter. The data on which the assessment

The MHLW also asked us to conduct a risk change

was based came from actual contamination data in theassessment when reviewing SRM in relation to OIE.

chicken production and distribution fields. The positive

In concrete terms, the Ministry asked us to carry out

ratio of Campylobacter-infected chickens was quite highthe same kind of assessment on Japanese beef, US andat the farm stage, for example, and the contamination

Canadian beef, and beef imported from France and thepersisted throughout the distribution and slaughtering

Netherlands, although beef imports from the latter twostages. Due to cross contamination, the test-positive

countries are currently prohibited.

ratio increases during the slaughtering process. In

2nd Live Love Animals International Conference on Animal Care in Kobe 2012207

addition, an important characteristic of Campylobacter-chicken raw. And we estimated how far the number

caused food poisoning is that it can occur if even aof affected individuals could be reduced through asmall number of these bacteria contaminate foodcombination of measures such as maintaining thoroughduring the cooking or consuming stages. The recent

control over the chlorine concentration in poultry

popularity of eating chicken raw is considered a major

slaughtering facilities. According to our assessment, if

factor in the spread of this food poisoning.

Japanese people would reduce the number of occasions
on which they ate raw chicken by 80%, then the

In risk assessment, it is necessary to consider thenumber of people infected with food poisoning frompossibility of infection at each stage and also theraw chicken would decline by 70% compared with thepossibility of cross contamination. Firstly, we checkpresent situation. This assessment includes anotherthe situation at the farm stage, then at the poultry

estimate of how far the number of infected peopleslaughtering stage including the possibility ofwould decline if poultry slaughtering facilities engaged

cross contamination when slaughtering. During thein sectioned processing and implemented thoroughslaughtering process, chlorine concentration control

chlorine concentration control in addition to consumers

at the water processing stage is used as a means of

reducing the number of occasions on which they ate

minimizing infection. Many factors such as these

raw chicken.

are involved at each processing stage. In this risk
assessment, we proceeded with the aim of clarifying

The results of such risk assessments are reported to

the following points scientifically, based on the data

the MHLW and the MAFF, which are the supervisingcollected. These points concern what is the actual

authorities. Regarding the present situation, sincedegree of risk in the current situation and how

receiving this particular risk assessment result, theconcretely will the risk of infection be changed when

MHLW and MAFF have been conducting their own

measures are taken at each stage? As an example ofresearch and surveys with a view to drawing up specificthe results of the process, this is an estimate of thecontrol measures. Also, they are issuing more strongly-

probability of infection. This risk assessment wasworded cautions to the general public to stop eating

conducted based on a model. The probabilities of

raw chicken.

infection in the case of eating raw meat and in the caseof not eating raw meat are generated. People who eat

Last year, we also carried out a risk assessment

raw meat become infected approximately 3.4 times

concerning enterohemorrhagic Escherichia coli or

per year. But even those who don’t eat raw meat have

EHEC, which was mentioned earlier by Prof. Morita.

a higher than zero risk — actually, it’s 0.36 times per

One of the characteristics of this bacterium is that anyear— due to the possibility of cross contamination.

infection can lead to food poisoning symptoms even

There is nothing particularly surprising about this.

if the number of bacteria present is relatively small.

It demonstrates the risk of eating raw meat. The risk

As a result of such contamination, cases in whichof infection is high for people who eat raw chicken,

EHEC contamination of beef and beef liver causes

although becoming infected is not necessarily the same

food poisoning are seen. In the same way as withthing as exhibiting symptoms.

Campylobacter, there is no need for concern about
EHEC food poisoning when meat, including chicken, is

In addition, we made assessments of how the risk

sufficiently heated prior to serving.

of infection changes when specific measures are208

taken at each stage. For example, we assessed how

As for the current situation in Japan, at the farm stage,effective it was at the poultry slaughtering stage when

as was mentioned earlier, in some of the facilities

slaughtering facilities made a distinction between

monitored, more than 10% of the livestock are infected.

chicken from contaminated farms and those from

Although the rate of infection varies according to theuncontaminated farms, or when people stopped eating

season, a certain amount of contamination is always

りぶ・らぶ・あにまるず 神戸アニマルケア国際会議 2012

present. Next, we come to the bacteria detection ratio

minutes at a depth of more than one centimeterfrom carcasses after slaughtering treatment. This varies

from the surface. The standard also specifies otherfrom year to year within the level shown here. In recent

things including temperature control. The reason foryears, the detection ratio has declined significantly,

specifying heating to more than 60 ℃ for more thanbut still a certain amount of EHEC contamination is

two minutes is that, in the course of various researchdetected. At the consumption stage, if food is tested, aconducted by the MHLW, it was found that when E. coli

certain amount of contamination can be detected too.

0157 becomes attached to the surface of whole cuts ofmeat, depending on the number of days passed since

In this type of risk assessment, the amount of bacteria

the animal was slaughtered, the bacteria on the surface

present is a factor. There is a report of an incident

will move to locations inside the meat. For this reason,

where - to give an example of the minimum number of

it is necessary to heat the meat not only on the surface

bacteria that can produce symptoms - food poisoning

but also to a certain depth (in order to eliminate thedeveloped from just two colony-forming units (CFUs).

bacteria).

Similarly, there are other cases in which people havedeveloped food poisoning from ingesting very few

The MHLW’s idea is that its ultimate target is to holdpathogenic bacteria.

down the number of deaths caused by E. Coli O157
annually to less than one person. Based on the number

In April and May of last year (2011), there was aof past deaths and the E. Coli O157 contamination ratio

succession of deadly food poisoning incidents in Japanof meat up until now, the Ministry decided to target the

involving "yukhoe" (a Korean dish of spiced ground beefamount of microorganism contamination of meat at theserved raw). In response to these incidents, the MHLW

time of consumption. Specifically, the Ministry set out

decided to establish a new standard for foods intended

a target limit of 0.014cfu/g (colony-forming units per

for raw consumption based on the Food Sanitation Act.

gram). Moreover, because microorganisms propagate

Accordingly, in April of last year, the FSCJ received aduring both the processing and consuming stages, inrequest to conduct a risk assessment, and this is thatthe interest of safety, the Ministry set a target limit forrisk assessment. Before that time, the MHLW set out

contamination by microorganisms at the processing

guidelines, issued notices concerning these guidelines

stage of 10% of the consumption time limit, orand provided related guidance to business operators, in

0.0014cfu/g. Also, the Ministry’s standard specifies the

addition to taking measures to boost public awarenessnecessary measures for achieving this target including

among consumers. However, after it became clear that

how to heat the meat and how to conduct inspections

eating yukhoe was causing food poisoning fatalities,

to verify whether or not the target has been reached.

the Ministry decided to set out a standard based on theFoot Sanitation Act backed up by force of law and with

The outline of the standard is as written here. In

penalties for infringement. Prior to establishing thisaddition, meat intended for raw consumption should

regulation, the Ministry requested the FSCJ to conduct

test negative for contamination by members of thea health impact assessment to serve as the basis forEnterobacteriaceae family. Specifically, the main

formulating the standard.

hazards are EHEC and Salmonella bacteria. But inthe case of meat for raw consumption the index

This assessment was compiled and summarized by lastfor the test is that the meat should be free from all

August and the results reported to the MHLW, afterEnterobacteriaceae bacteria contamination. Of course,which the new regulation came into force in Octobervarious hygiene requirements during the preparationof last year. Regarding the outline of the standard set

stage are also specified.

by the Ministry for beef intended for raw consumption,
the main points are that the meat must be heat treatedThis is an outline of the assessment resultsby heating it to more than 60

summarized by the FSCJ in August of last year. To℃ for more than two

2nd Live Love Animals International Conference on Animal Care in Kobe 2012209

be on the safe side, the MHLW’s indicated target

year, the MHLW set a provisional regulation value forlimit for microorganism contamination at the time ofradioactivity, and this is now used to regulate foodconsumption is set low.

distribution. In addition, when there is a possibilityof radioactive contaminated food in excess of the

Furthermore, the Ministry has set the target limit

regulation value being distributed across a region,

for microorganism contamination at the processing

instructions are issued about shipment restrictions andstage to make a considerable allowance for safety

intake restrictions within that region. These instructions

under conditions of hygienic management. One ofare not issued by the MHLW but by the Prime Minister

the conditions is that no parts of the meat that haveor the Government’s Nuclear Emergency Response

not been heat treated should be eaten raw, andHeadquarters to the prefectural governors concerned.

because there is no guarantee that the target level of

In either case, regulation based on the provisional

contamination can be achieved by complying with theregulation value remains in force at present. Since theheating-up process standard alone, it is also necessary

nuclear accident created an emergency situation, theto conduct bacteriological testing with the necessary

provisional regulation value was set in March of last

number of samples. This is a point concerning theyear without any prior assessment from the FSCJ. After

FSCJ’s assessments that was not contained in thethe accident, the FSCJ received a request to conduct

MHLW’s request. Specifically, it is necessary to test 25

an assessment from the MHLW. The FSCJ sent back a

specimens weighing 25g each. The FSCJ also added thesummary of its results in October. Armed with thesecaveat to its assessment that validation of the system isresults, the MHLW has been conducting concrete

an indispensible element of the heating method.

studies since April of this year in preparation for setting
a new regulation value.

As a result, we can say that meat satisfying the above
standard is assured quite a high level of safety. But,

Moving on to the health effects of radioactive

even so, the MHLW does not guarantee a zero risk or

contamination, these can be divided roughly into

100% safety. At the Ministry’s council, deliberations“deterministic” effects and “probabilistic” effects. The

proceeded from the standpoint that, basically, people

deterministic effects, which occur at comparatively

should avoid eating raw meat. The FSCJ also takes thehigh doses, include hair loss and infertility. In the

stance that, particularly in the case of children, thepresent situation, doses are not at a level that shouldelderly, and those with lower levels of natural immunity

cause worry about deterministic effects. Regarding

to the microorganisms that cause food poisoning,

the probabilistic effects of low doses, it is necessary

attention should be paid to avoid eating raw or

to consider the risk of cancer including leukemia. As

undercooked meat.

for the relationship between cancer risk and radiation,
radioactive material can emit three types of radiation,

In addition, the MHLW’s council is continuously

known respectively as alpha particles, beta particles anddiscussing the handling of raw liver. Administratively,

gamma rays, when unstable isotopes change into stable

it is known that in December of last year, as a result

isotopes. Beta particles are fast moving electrons, whileof research by the Ministry, E. coli and EHEC were

gamma rays are high-energy electromagnetic waves,detected in liver. If it becomes necessary, the Ministryor photons. High-energy radiation of this kind canwill issue an assessment request concerning this issue

damage the DNA in the cells of living things including

to the FSCJ.

human beings. Basically, our bodies are equipped withfunctions that can repair this damage, but occasionally,

Next, I would like to talk about the risk assessment

probabilistic damage can remain without being

situation related to radioactive contamination.

repaired in the form of a mutation that causes a cell to
become cancerous. Despite the body’s natural defense

When the nuclear accident occurred in March of last210

りぶ・らぶ・あにまるず 神戸アニマルケア国際会議 2012mechanisms, if such a cell can survive in the immune

system, it may propagate and grow into a cancer. Suchstudied this subject using epidemiological data thatdevelopments are probabilistic effects that depend inincluded external exposure as well. Both internal andpart on the amount of radioactive material present inexternal exposures are quantified using a common

the body.

unit, namely, the sievert. Accordingly, if there happens
to be some data in which individual doses are given

Radioactivity is said to have caused genetic effects inin sieverts, this data can be used for food health effectanimal experiments, but in research on humans, suchassessment, so we studied this data as well.

effects have not been detected. In the ongoing researchon the atomic bomb victims of Hiroshima and Nagasaki,

Internationally, in this kind of assessment, the linear

no clear genetic effects have been shown statistically

non-threshold model is used, particularly for high

up to the present time.

doses. For example, there is a finding that the mortality
risk from cancer increases by 5% at a dose of 1,000

At this point, let me talk a little bit about becquerels

milisieverts. Under the present situation, hypothetically,and sieverts. The becquerel is the unit employeda risk exists in proportion to the radiation dose even if

to quantify radioactive contamination in food, etc.,

the dose is small, and risk management is carried out

Essentially, it measures the strength of the radioactive

accordingly. Actually, whether or not there is a realemissivity of the substance being measured. However,health risk at low doses has not been proven, but risk

when radiation enters the body in food, which results inmanagement is conducted based on the hypothesis thatinternal exposure, the unit used to quantify the severity

the risk is real.

of the effect on health is the sievert. Radioactive
emissivity differs according to the type of radioactive

On the other hand, the FSCJ’s role is to clarify thismaterial and the type of radiation emitted, such as betarisk based on scientific knowledge, so we haveparticles or gamma rays, but conversion factors based

studied this risk based on epidemiological data on

on scientific knowledge have been established for eachpeople who have been exposed to radiation. This isof these types. There is also a conversion factor fromthe epidemiological data we used. The first is frombecquerels to sieverts, and this can be used to put a

the State of Kerala in southern India, a region where

numerical value on the scale of the effect of internal

natural background radiation is relatively high due toexposure.

there being comparatively large amounts of radioactive
thorium in natural sand deposits. The results of thisIn the food health effect assessment we conducted thissurvey, which followed 70,000 residents in Kerala

time, we studied approximately 3,300 domestic andover a ten-year period, showed no increase in the riskinternational documents beginning with publications byof developing cancer. According to the report, despite

UNSCEAR (the United Nations Scientific Committee onsome very high doses (including cumulative doses as

the Effects of Atomic Radiation), the ICRP (International

high as 500 milisieverts) the researchers found no link

Commission on Radiological Protection, and the WHOto carcinogenesis. However, in the case of atomic bomb

(World Health Organization). In order to clarify thevictim data from Hiroshima and Nagasaki, the mortality

relationship between doses and health effects, werisk from leukemia was found to rise statistically atclosely examined documents with a focus on whether

above a borderline level of 200 milisieverts. The results

such radiation dose estimates are reliable or not, and onof an epidemiological survey that had followed almost

whether research methods for epidemiological studies

100,000 people for 47 years, in the case of a groupare appropriate or not.

that had experienced radiation exposure of between
zero and 125 milisieverts, showed a statistical rise inRegarding the health effects of radioactive

mortality risk due to carcinoma. But this rise couldn’contamination ingested via food, since epidemiologicalt be confirmed in a group that experienced radiation

data on internal exposure has been very limited, we

exposure of between zero and 100 milisieverts. So the

2nd Live Love Animals International Conference on Animal Care in Kobe 2012211

risk only becomes visible statistically when radiation

sensitivity is higher than in the period of adulthood.

exposure levels rise above 100 milisieverts.

This is what was stated in a document dealing with
the Chernobyl accident. But we could not share thisThis is a document concerning the effects of radiation

conclusion because on close examination the data wason children. According to the text, available data

uncertain with respect to dose estimation. However, theindicates that children are generally more sensitive

possibility of this conclusion being correct is high, soto the effects of high radiation doses. However, thethe FSCJ has included it within the summary. Regarding

epidemiological data is extremely limited concerning

the health effects of doses below 100 milisieverts,

children exposed to low radiation doses, as in the casewe were unable to refer to this data. Although thereof the Fukushima Daiichi nuclear accident. We also

is a document stating adverse health effects evenstudied two documents concerning Chernobyl. One

at doses below 100 milisieverts, we were unable toof them reports that the risk of leukemia was higher

employ it because the theoretical estimates used wereamong children aged less than five years. There wasincorrect. More than anything, the risk of developing

also a document stating that the younger the age whencancer is affected by a long list of things ranging fromradiation victims were exposed, the higher their risk ofconsuming alcohol or tobacco to lack of vegetables,developing thyroid cancer. However, when we looked atlack of exercise, etc., and there is a possibility that thethis document from an epidemiological and statisticaleffects of these various risk factors and the effects

perspective, we found that the dose estimates were

due to exposure to low doses of radiation are notimprecise in certain respects. Accordingly, the FSCJ

clearly distinguished. As FSCJ assessments should be

judged that uncertainties remain concerning the risk

made statistically and epidemiologically, and given thefrom exposure to a given dose of radiation.

small size of the epidemiological data, such small risk
differences could not be detected, although there is a

The next piece of data I want to show you concerns

possibility that such differences are real. From this, thethe effects of exposure to radiation on fetuses. This is

FSCJ decided that it was difficult to make a judgment

the outline of an assessment we carried out in Octoberregarding the sensitivity of children to low doses ofof last year based on other documents and the results

radiation.

of an epidemiological survey. The effects of radiation
exposure can be seen when the lifetime additional

This is the result of the FSCJ assessment in which we

cumulative effective dose climbs to approximately 100

considered that approximately 100 milisieverts is themilisieverts. The significance of the term “additional”

borderline between safety and danger. This is not ahere is that, even before the Fukushima Daiichi nuclear

scientifically determined border because it has notaccident, people were exposed to natural radiation

yet been made clear scientifically that a person whoin the course of their everyday lives. For Japan, thereceives a radiation dose higher than 100 milisieverts

natural background radiation level is in the order ofalways develops cancer, or that a person who receives

1.5 milisieverts annually. Also, we are occasionallya dose lower than 100 milisieverts has no risk of

exposed to radiat ion in the course of medical

developing cancer at all. But it does represent a value

examinations. When there is additional food-mediatedthat risk management organizations can consider whenradiation, beyond such natural background and medical

conducting risk management.

examination-related radiation, and reaching 100
milisieverts, the effects of radiation exposure begin to

Cancer has a variety of causative factors, and to prevent

be seen. Specifically, we evaluated that a risk of cancer

cancer there are also many factors that can play aoccurred at this level.

role such as eating lots of vegetables and exercising,
etc. Individuals themselves need to consider which

212

The words here state, “during life”. But in the summary

preventative measures they should take for preventing

it specifies that during the period of childhood,the likelihood of cancer.

りぶ・らぶ・あにまるず 神戸アニマルケア国際会議 2012

In this slide, you can see the radiation dose that

below 5 milisieverts per year, with the dosage divided

Japanese people were receiving from the natural world

between specific foods. But the new regulation values

before the nuclear accident. The Japanese receive

are based on the FSCJ’s assessment results, etc., andabout 1.5 milisieverts per year from such naturaldesigned to keep exposure below 1 milisieverts per

sources. So in the course of his or her life so far, ayear.

70-year-old Japanese would have cumulatively received
approximately 100 milisieverts. This breaks down

The dividing method employed is as follows. In

into radiation received from cosmic rays and from theaddition to cesium, food contamination with strontium

ground or soil. There is also some radioactive radonor plutonium is considered a possibility. The MHLW

and thoron within the atmosphere so there is some

explained the thinking behind the new regulation values

internal exposure when we inhale. On top of that, we

as follows. By setting this low limit for radioactive

take in the equivalent of 0.4 milisieverts of radiation

cesium, any hidden radioactive effects from strontium

per year from food.

or plutonium will also be controlled.

The radioactive substances in food include potassium

The method used for dividing the regulation value

40. Potassium is a naturally occurring element

among specific types of food in order to set the newand a necessary component within living things.

regulation values was to first remove the portion

Approximately 0.012% of naturally occurring potassiumfor drinking water and then to divide the remainder

is the radioactive isotope potassium 40. Since the half-among the various general foods. Naturally, the amountlife of this isotope is very long (at 1.2 or 1.3 billionof food people consume varies according to age, so

years) it continuously remains present in food. So there

sensitivity to radioactivity likewise differs according tois always a certain amount of radioactive potassium 40

age. Accordingly, the maximum values are calculated bypresent in all foods containing potassium. Also, if wepaying consideration to these aged-related variations incheck dried food, we always detect a certain level ofconsumption volume and sensitivity to radiation.

radioactivity. In this assessment, the FSCJ addressed theissue of how things stand when radioactivity from foodIn terms of age categories, to take babies aged lessis added to the radioactivity exposure from other areas

than one year old for example, since the volume ofof our lives in order to provide a guide to cancer risks

food they consume is small, if a limit value of 460

when food-mediated radioactive exposure increases

becquerels is set, their radiation intake will not be inabove 100 milisieverts.

excess of 1 milisievert per year. By contrast, to take theexample of adolescent boys aged 13 to 18, since they

Since receiving this assessment in October of last year,

tend to have large appetites, a radiation intake of no

the MHLW has been reviewing its specific standard

more than 1 milisievert per year cannot be guaranteed‘values’. This is the provisional regulation value set inunless a limit value of 120 becquerels is set for food.

March of this year. For example, in the case of meat,

The MHLW’s thinking was to make this calculation

an upper limit of 500 becquerels has been established,for each generation or age group, and then, based on

although this will be reviewed in April. Under the new

the most severe case (which was 120 becquerels) toregulation value plan, the classification is also being

set the regulation value even lower at 100 becquerels.

reviewed. According to the new regulation value idea,

Also, in this calculation, the value was set based on thethe regulation values are 10 for drinking water, 50 for

idea that half of the food people eat is contaminated bymilk, 100 for general food and 50 for baby and infant

radioactive material.

food.
Concerning this point, some people have voiced the
The provisional regulation values were decided with

opinion that, in practice, it could never happen thatthe idea of keeping exposure to radiation from cesium

50% of the food people eat was contaminated, but the

2nd Live Love Animals International Conference on Animal Care in Kobe 2012

213

MHLW made this calculation expressly to ensure amost of food bought was produced locally, the level ofconsiderable margin of safety.

radioactive cesium detected was at a very low level equivalent to an annual dose of just 0.02 milisieverts.

The Ministry makes estimates of how much radioactive

So, when actually distributed foods were examined, theymaterial people are ingesting from food. Currently,

were found to contain only tiny amounts of radioactive

each municipality is testing food. Based on the results

cesium even when compared to the levels of naturallyof these tests, using laboratory data covering theoccurring radioactive potassium.

period from August to November of last year, andalso on the assumption that no contaminated food

Although this is the actual situation, the MHLW has set(contaminated with radioactive material in excess ofout regulation values with the aim of guaranteeing a

the new regulation limit) is distributed, in the case thatconsiderable margin of safety.

food contaminated at levels below the regulation value
is distributed, the Ministry estimates how many sieverts

From this January, the MHLW and the FSCJ began

per year of radioactivity people who eat this food will

jointly holding a series of explanatory meetings in

be exposed to.

various regions concerning the presence of radioactive
material in food. In Kansai, a meeting is scheduled to

According to a calculation made using the median value

take place in Osaka on February 28.

of the test results, the radioactivity intake is 0.043
milisieverts per year. Likewise, when a calculation is

Lastly, we are undertaking the various efforts I havemade on the assumption that people eat food withintroduced here as part of the FSCJ’s approach to risk

levels of radioactivity comparatively higher than thosecommunication. On the FSCJ’s website, you’ll findof 90% of the samples recorded in the laboratory result

the answers to a wide range of FAQs concerning thedata, the intake rises to 0.074 milisieverts. So, on theradioactive contamination and food poisoning issues, sobasis of these calculations, we can expect levels of

I hope you will make good use of this information.

actual exposure to be quite low.
Thank you very much for your attention.
Actually, this laboratory testing was mainly carried out
on food produced in eastern Japan, which means thefood had comparatively high levels of contamination(from a national average standpoint). Even so, theestimate shows this rather low result.
To carry out its tests, the MHLW bought food that wason sale locally in Tokyo, Miyagi and Fukushima, andchecked how much radioactive material the foodstuff
contained. This slide shows the results in various
regions. Earlier, I said that food contains potassium
and that a certain amount of it occurs in the formof the radioactive isotope potassium 40. What thismeans is that food contains the equivalent of an annual
dose of 0.2 milisieverts of potassium. The Ministry
also checked how much radioactive cesium 134 and137 are contained in this food. In the case of various
regions of Tokyo, the levels were extremely low. In thecase of Miyagi and Fukushima, despite the fact that the214

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