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Lead contamination of cornflour risk assessment and consumption data
A risk assessment was performed for products that contained lead contaminated cornflour and this risk assessment was the basis for deciding whether the product should be recalled.
The risk assessment involved:
• Identifying all product types containing the lead contaminated cornflour.
• Determining the percentage levels of cornflour in the final product.
• Determining the possible level of lead in the cornflour. The highest level used was 23mg/kg (highest test result from Penford was 22.3mg/kg). It should be noted however that not all products would have carried this level.
• The assumption that 100% of the lead was bioavailable*, however this was the worst case scenario as most forms of lead are less than 100% bioavailable.
• Comparing calculated levels (or actual levels where results were available) of lead in the final product with known regulatory limits for lead.
• Taking into account any known consumption data in comparison with food types with regulatory lead limits.
• Consideration of whether the product is currently available (i.e. shelf-life, distribution data, etc).
• Consideration of the maximum level of exposure to lead from all food sources containing contaminated cornflour.
All Maximum Permissible Limits (MPL’s) set for food were considered. Cereal was referenced as it would apply to the corn. Molluscs have the highest MPL for a food so was used for comparison purposes (i.e how do the lead levels in mixed foods compare to a food that has the highest defined MPL). As mixed foods do not have defined MPL's, but depend on a complicated set of calculations that include all MPL's for the specific ingredients in the food, this system of calculation and assessment was employed to allow a determination of acceptability rather than running through each individual ingredient and performing a separate calculation.
Abbreviations and terms used in the tables are:
RTE Ready to Eat
PTWI Provisional Tolerable Weekly Intake
PPM Parts per million
*Bioavailable The term ‘bioavailable’ describes the ability of a drug or other substance to be absorbed and used by the body; or the degree to which a contaminant in environmental media can be assimilated by an organism. For example, if contaminated soil is ingested by a bird, the subsequent bioavailability of the contaminant will be dependent upon its uptake through the gut wall of the bird.
Lead Contamination of Cornflour
A summary of results, by product type, is shown below.
Product |
Percent Cornflour in RTE Product |
Lead in product (ppm) |
Acceptable? |
Justification |
Biscuit (Average level of cornflour added) |
1.370% |
0.3151 |
Y |
1.5 x cereal MPL of 0.2ppm |
Biscuit (High level of cornflour added) |
10.390% |
2.3897 |
Y |
MPL for molluscs = 2ppm, consumption data indicates intake of lead from this source 59% (max) of intake from molluscs at regulatory limit |
Biscuit (Low level of cornflour added) |
0.020% |
0.0046 |
Y |
Below cereal MPL of 0.2ppm |
Cereal based Product (High Level of cornflour added) |
1.180% |
0.2714 |
Y |
1.5 x cereal MPL of 0.2ppm |
Cereal based Product (Low level of cornflour added) |
0.100% |
0.023 |
Y |
Below cereal MPL of 0.2ppm |
Confectionery |
0.001% |
0.00023 |
Y |
Below cereal MPL of 0.2ppm |
Sauce/dressing |
2.860% |
0.6578 |
Y |
3 x cereal MPL of 0.2ppm |
Snack Bar |
2.500% |
0.575 |
Y |
1.5 x cereal MPL of 0.2ppm |
Lead Contamination of Cornflour - Consumption Data
To estimate the maximum level of exposure to the lead hazard, consumption data was determined (from National Nutrition Surveys) for each of the product types examined. This was then used to provide a maximum estimate of lead intake. It assumed that a person ate all the product types containing lead contaminated cornflour, and that 100% of the daily intake, within the product-type category, was of product containing the lead contaminated cornflour. This data was considered in the risk assessment.
Children
Table 1
Assumes all product categories are eaten at maximum consumption amount, so is an overestimate of consumption (i.e maximum consumption data is applied against each individual category, e.g 3 categories of biscuit each with maximum consumption data rather than adjusting consumption data across the 3 categories)
Product |
Percent Cornflour in RTE Product |
product consumed/day (g) |
product consumed/week (g) |
Amount cornflour consumed (g) |
Amount of lead consumed (g) |
g Lead/kg Body weight - 35kg child |
Weekly Intake (ug/kg bw/wk) |
%PTWI |
Biscuit (Average) |
1.370% |
31 |
217 |
2.9729 |
6.838E-05 |
1.95362E-06 |
1.95362 |
7.81448 |
Biscuit (High) |
10.390% |
31 |
217 |
22.5463 |
0.0005186 |
1.48161E-05 |
14.81614 |
59.26456 |
Biscuit (Low) |
0.020% |
31 |
217 |
0.0434 |
9.982E-07 |
2.852E-08 |
0.02852 |
0.11408 |
Cereal based Product |
1.180% |
183 |
1281 |
15.1158 |
0.0003477 |
9.93324E-06 |
9.93324 |
39.73296 |
Cereal based Product |
0.100% |
183 |
1281 |
1.281 |
2.946E-05 |
8.418E-07 |
0.8418 |
3.3672 |
Confectionery |
0.001% |
26 |
182 |
0.00182 |
4.186E-08 |
1.196E-09 |
0.001196 |
0.004784 |
Sauce/dressing |
2.860% |
10 |
70 |
2.002 |
4.605E-05 |
1.3156E-06 |
1.3156 |
5.2624 |
Snack Bar |
2.500% |
33 |
231 |
5.775 |
0.0001328 |
0.000003795 |
3.795 |
15.18 |
TOTAL INTAKE |
49.73822 |
0.001144 |
3.26851E-05 |
32.68512 |
130.7405 |
|||
PTWI |
25 |
Table 2
Adjusts for consumption across product categories and assumes maximum consumption of the categories with the highest levels of cornflour.
Product |
Percent Cornflour in RTE Product |
product consumed/day (g) |
product consumed/week (g) |
Amount cornflour consumed (g) |
Amount of lead consumed (g) |
g Lead/kg Body weight - 35kg child |
Weekly Intake (ug/kg bw/wk) |
%PTWI |
Biscuit (High) |
10.390% |
31 |
217 |
22.5463 |
0.0005186 |
1.48161E-05 |
14.81614 |
59.26456 |
Cereal based Product |
1.180% |
183 |
1281 |
15.1158 |
0.0003477 |
9.93324E-06 |
9.93324 |
39.73296 |
Confectionery |
0.001% |
26 |
182 |
0.00182 |
4.186E-08 |
1.196E-09 |
0.001196 |
0.004784 |
Sauce/dressing |
2.860% |
10 |
70 |
2.002 |
4.605E-05 |
1.3156E-06 |
1.3156 |
5.2624 |
Snack Bar |
2.500% |
33 |
231 |
5.775 |
0.0001328 |
0.000003795 |
3.795 |
15.18 |
TOTAL INTAKE |
45.44092 |
0.0010451 |
2.98612E-05 |
29.86118 |
119.4447 |
|||
PTWI |
25 |
Table 3
Adjusts for consumption across product categories and assumes equal consumption over all related categories (e.g, 1/3 consumption amount in each of 3 biscuit categories).
Product |
Percent Cornflour in RTE Product |
product consumed/day (g) |
product consumed/week (g) |
Amount cornflour consumed (g) |
Amount of lead consumed (g) |
g Lead/kg Body weight - 35kg child |
Weekly Intake (ug/kg bw/wk) |
%PTWI |
Biscuit (Average) |
1.370% |
10.3 |
72.1 |
0.98777 |
2.272E-05 |
6.49106E-07 |
0.649106 |
2.596424 |
Biscuit (High) |
10.390% |
10.3 |
72.1 |
7.49119 |
0.0001723 |
4.92278E-06 |
4.922782 |
19.69113 |
Biscuit (Low) |
0.020% |
10.3 |
72.1 |
0.01442 |
3.317E-07 |
9.476E-09 |
0.009476 |
0.037904 |
Cereal based Product |
1.180% |
91.5 |
640.5 |
7.5579 |
0.0001738 |
4.96662E-06 |
4.96662 |
19.86648 |
Cereal based Product |
0.100% |
91.5 |
640.5 |
0.6405 |
1.473E-05 |
4.209E-07 |
0.4209 |
1.6836 |
Confectionery |
0.001% |
26 |
182 |
0.00182 |
4.186E-08 |
1.196E-09 |
0.001196 |
0.004784 |
Sauce/dressing |
2.860% |
10 |
70 |
2.002 |
4.605E-05 |
1.3156E-06 |
1.3156 |
5.2624 |
Snack Bar |
2.500% |
33 |
231 |
5.775 |
0.0001328 |
0.000003795 |
3.795 |
15.18 |
TOTAL INTAKE |
24.4706 |
0.0005628 |
1.60807E-05 |
16.08068 |
64.32272 |
|||
PTWI |
25 |
Adults
Table 1
Assumes all product categories are eaten at maximum consumption amount, so is an overestimate of consumption (i.e maximum consumption data is applied against each individual category, e.g 3 categories of biscuit each with maximum consumption data rather than adjusting consumption data across the 3 categories).
Product |
Percent Cornflour in RTE Product |
product consumed/day (g) |
product consumed/week (g) |
Amount cornflour consumed (g) |
Amount of lead consumed (g) |
g Lead/kg Body weight – 70kg adult |
Weekly Intake (ug/kg bw/wk) |
%PTWI |
Biscuit (Average) |
1.370% |
40 |
280 |
3.836 |
8.823E-05 |
1.2604E-06 |
1.2604 |
5.0416 |
Biscuit (High) |
10.390% |
40 |
280 |
29.092 |
0.0006691 |
9.5588E-06 |
9.5588 |
38.2352 |
Biscuit (Low) |
0.020% |
40 |
280 |
0.056 |
1.288E-06 |
1.84E-08 |
0.0184 |
0.0736 |
Cereal based Product |
1.180% |
372 |
2604 |
30.7272 |
0.0007067 |
1.00961E-05 |
10.09608 |
40.38432 |
Cereal based Product |
0.100% |
372 |
2604 |
2.604 |
5.989E-05 |
8.556E-07 |
0.8556 |
3.4224 |
Confectionery |
0.001% |
55 |
385 |
0.00385 |
8.855E-08 |
1.265E-09 |
0.001265 |
0.00506 |
Sauce/dressing |
2.860% |
16 |
112 |
3.2032 |
7.367E-05 |
1.05248E-06 |
1.05248 |
4.20992 |
Snack Bar |
2.500% |
55 |
385 |
9.625 |
0.0002214 |
3.1625E-06 |
3.1625 |
12.65 |
TOTAL INTAKE |
79.14725 |
0.0018204 |
2.60055E-05 |
26.00553 |
104.0221 |
|||
PTWI |
25 |
Adults (cont)
Table 2
Adjusts for consumption across product categories and assumes maximum consumption of the categories with the highest levels of cornflour.
Product |
Percent Cornflour in RTE Product |
product consumed/day (g) |
product consumed/week (g) |
Amount cornflour consumed (g) |
Amount of lead consumed (g) |
g Lead/kg Body weight - 70kg adult |
Weekly Intake (ug/kg bw/wk) |
%PTWI |
Biscuit (High) |
10.390% |
40 |
280 |
29.092 |
0.0006691 |
9.5588E-06 |
9.5588 |
38.2352 |
Cereal based Product |
1.180% |
372 |
2604 |
30.7272 |
0.0007067 |
1.00961E-05 |
10.09608 |
40.38432 |
Confectionery |
0.001% |
55 |
385 |
0.00385 |
8.855E-08 |
1.265E-09 |
0.001265 |
0.00506 |
Sauce/dressing |
2.860% |
16 |
112 |
3.2032 |
7.367E-05 |
1.05248E-06 |
1.05248 |
4.20992 |
Snack Bar |
2.500% |
55 |
385 |
9.625 |
0.0002214 |
3.1625E-06 |
3.1625 |
12.65 |
TOTAL INTAKE |
72.65125 |
0.001671 |
2.38711E-05 |
23.87113 |
95.4845 |
|||
PTWI |
25 |
Adults (cont)
Table 3
Adjusts for consumption across product categories and assumes equal consumption over all related categories (e.g, 1/3 consumption amount in each of 3 biscuit categories).
Product |
Percent Cornflour in RTE Product |
product consumed/day (g) |
product consumed/week (g) |
Amount cornflour consumed (g) |
Amount of lead consumed (g) |
g Lead/kg Body weight - 70kg adult |
Weekly Intake (ug/kg bw/wk) |
%PTWI |
Biscuit (Average) |
1.370% |
13.5 |
94.5 |
1.29465 |
2.978E-05 |
4.25385E-07 |
0.425385 |
1.70154 |
Biscuit (High) |
10.390% |
13.5 |
94.5 |
9.81855 |
0.0002258 |
3.2261E-06 |
3.226095 |
12.90438 |
Biscuit (Low) |
0.020% |
13.5 |
94.5 |
0.0189 |
4.347E-07 |
6.21E-09 |
0.00621 |
0.02484 |
Cereal based Product |
1.180% |
186 |
1302 |
15.3636 |
0.0003534 |
5.04804E-06 |
5.04804 |
20.19216 |
Cereal based Product |
0.100% |
186 |
1302 |
1.302 |
2.995E-05 |
4.278E-07 |
0.4278 |
1.7112 |
Confectionery |
0.001% |
55 |
385 |
0.00385 |
8.855E-08 |
1.265E-09 |
0.001265 |
0.00506 |
Sauce/dressing |
2.860% |
16 |
112 |
3.2032 |
7.367E-05 |
1.05248E-06 |
1.05248 |
4.20992 |
Snack Bar |
2.500% |
55 |
385 |
9.625 |
0.0002214 |
3.1625E-06 |
3.1625 |
12.65 |
TOTAL INTAKE |
40.62975 |
0.0009345 |
1.33498E-05 |
13.34978 |
53.3991 |
|||
PTWI |
25 |
New Zealand Food Safety Authority
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Phone: +64 4 894 2500
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