Aflatoxin production by Mold -L14

Question 1

Why does fungi not always produce aflatoxin ?

Answer 1

toxin is only produced (but not always) at high temperatures and high humidity
therefore in the EU aflatoxin isn’t produced

Question 2

When can the toxin be produced?

Answer 2

during growth of the crop

often produced during storage

Question 3

What is peculiar about the production of aflatoxin?

Answer 3

it is highly non-uniform
e.g. few nuts may be highly contaminated but the majority will have undetectable levels
this adds complexity, making it difficult to quantify

Question 4

Is it regulated?

Answer 4

it is regulated in most countries but its regulation varies between countries

Question 5

Why are regulations of 0 micrograms/kg not possible?

Answer 5

because 0 isn’t measured, you can only measure down to a detection level

Question 6

What is PTWI?

Answer 6

provisional tolerable weekly intake - tolerable intake, expressed on a weekly basis

Question 7

What is the “irreducible level” ?

Answer 7

concentration of a substance which cannot be eliminated from a food without involved the discarding of that food altogether, severely compromising the ultimate availability of food supplies - there are practical limits on how little aflatoxin can be present in food

Question 8

What is the irreducible level often referred to as and why is it difficult for risk managers to use?

Answer 8

the ALARA= as low as reasonably achievable

difficult because health effects are not quantified

Question 9

What is the quantitative risk assessment ?

Answer 9

relationship between intake of a contaminant and the probability of an adverse response in humans
e.g. adverse effect for aflatoxin= liver cancer
how likely is this response going to occur

Question 10

Why is the PTWI useful for risk managers?

Answer 10

it provides a line in which they can use to compare intake
- important to average consumption across the week because you may only consume one meal in that week with high consumption

Question 11

Why is determining a quantitative risk assessment for most contaminants difficult?

Answer 11

because data is lacking

Question 12

What 2 things to you need to know to determine the quantitative risk assessment ?

Answer 12

what is in different foods
how much those foods make up in a normal diet - link this to the probability of liver cancer occurring
if all this info is known then probability of any intake can be determined for an adverse response

Question 13

Why do we have a lot of information about aflatoxin b1 toxicity ?

Answer 13

due to animal studies

Question 14

What enhances the carcinogenic potency of aflatoxin b1?

Answer 14

simultaneous infection with hepatitis B
there is more of carcinogen if you also suffer from hepatitis b infection
hepatitis b already damages the liver

Question 15

What is the carcinogenic potency for aflatoxin in a persons negative for hepatitis b virus ?

Answer 15

0. 01 case per year/100,000people per ng of aflatoxin b1/ Kg body weight
   range: 0.002-0.03

Question 16

What is the carcinogenic potency for aflatoxin in a persons positive for hepatitis b virus ?

Answer 16

0.3 case per year/100,000people per ng of aflatoxin b1/ Kg body weight
range: 0.05-0.5
30 fold higher than in the absence of hepatitis B

Question 17

What is the population risk in the EU where aflatoxin b1 is low and people carrying hepatitis B is low ?

Answer 17

1%

Question 18

What is the population risk in parts of china where aflatoxin b1 is high and people carrying hepatitis B is higher ?

Answer 18

25%

Question 19

How were the population risk estimates determined ?

Answer 19

estimates are based on food consumption data
for EU the data is from measuring levels of aflatoxin B1 in groundnuts and maize
for parts of china the data is from measuring aflatoxin b1 in groundnuts and maize

Question 20

For these population risks what hypothetical standards were used?

Answer 20

10 microgram aflatoxins b1/Kg groundnuts or maize
and
20 microgram aflatoxins b1/Kg groundnuts or maize

Question 21

What is predicted for the 2 hypothetical standards used?

Answer 21

predicted that the more stringent standard, 20, would cause more product to be removed from the market and population risks should be lower

Question 22

What is the potency for the low risk group ?

Answer 22

0.01 * 99% + 0.3 * 1% = 0.013 cancers per year/100000 people per ng aflatoxin b1/Kg body weight per day

Question 23

Using the potency for the low risk group what is the intake of aflatoxins for 20 and 10 micrograms/kg standard ?

Answer 23

20= 19ng per person per day
10= 18 ng per person per day
this difference is very small because the most highly contaminated samples have been removed in both cases because the distribution of aflatoxin is not a normal distribution

Question 24

What are the risks for the lower risk groups now that the potency has been determined?

Answer 24

20micrograms/kg standard
- 19 * 0.013/ 60Kg = 0.0041 cancers per year per 100000 people

10micrograms/kg standard
- 18 * 0.013/60Kg= 0.0039 per year per 100000 people

therefore reducing the hypothetical standard from 20 to 10 yields a reduction in estimated population risk by 2 cancers per year per billion = tiny

Question 25

What is the potency for the higher risk group?

Answer 25

0.01 * 75% + 0.3 * 25% = 0.083 cancers per year/100000 people per ng aflatoxin b1/kg body weight per day

Question 26

Using the potency for the higher risk group what is the intake of aflatoxins for 20 and 10 micrograms/kg standard ?

Answer 26

20= 125ng per person per day
10= 103ng per person per day
difference is still small because the highly contaminated samples have been removed

Question 27

What are the risks for the higher risk groups now that the potency has been determined?

Answer 27

20micrograms/kg standard
- 125ng * 0.083/60Kg = 0.17 cancers per year per 100000 people
10micrograms/kg standard
- 103 * 0.083/60Kg= 0.14 cancers per year per 100000 people
reducing the hypothetical standards from 20 to 10 caused a reduction in estimated population risk by 300 cancers per year per billion people - TINY as well

Question 28

What were the selected conclusions from the JECFA after these results had been calculated?

Answer 28

vaccination against hepatitis B would reduce the potency of aflatoxins and therefore reduce the risk of liver cancer

the differences in populations risk are unlikely to be exhibited from going from 20 to 10 - wouldn’t make a huge difference

Question 29

What are the uses of potency estimates?

Answer 29

• used world wide because toxicity is an inherent property

- the JEFCA should update it frequently to ensure they are based on the latest info

Question 30

Why is it best to make estimates at national or local levels?

Answer 30

risks at international level can be at best indicative of risk but the precise information is lacking whereas at local level it can be more accurate as it is based on contamination levels and food consumption

Question 31

Therefore is it beneficial to have the strictest regulatory measures on aflatoxin?

Answer 31

the impact of lower eu aflatoxin standards upon african exports
number of deaths saved by stricter levels= 2 cancer cases per billion - wouldn’t even notice this
loss in africa exports of groundnuts and cereals would cost them 670 million US dollars- this would have a significant effect upon these growers

THEREFORE NOT ACTUALLY BEST IDEA TO HAVE STRICTEST LEVELS ON REGULATION