Section 5
Quality Control / Assurance
Quality Control / Assurance
Internal Quality Overview
Qualitative Testing, including iron spot test procedures
Record Keeping and Quality Control Schedule
Quantitative Testing and Composite Samples
Government’s Role In Monitoring
Quality Control / Assurance
An effective quality assurance and
quality control program throughout
a country’s flour fortification
program:
• Ensures adequate levels of
vitamins and minerals to improve
nutrition among the population
• Prevents the cost of over-using
premix
Ramadan Deliu, Head of Laboratory at M &
Sillosi Milling Company, prepares flour for an
iron spot test. Photo by Kate Wheeler.
• Gains customer satisfaction
• Adheres to government
regulations
Quality Control / Assurance
Five parts of the program
Internal
External
Commercial
Intake
Impact
Flour millers conduct process control and quality
checks
Food control authorities inspect flour mills and
analyze flour samples
Inspectors check fortified products at retail stores
Household surveys confirm consumption
Biological impact is verified
Source: Chapter eight of the Guidelines on Food Fortification with Micronutrients published by the World
Health Organization and the Food and Agricultural Organization of the United Nations
Quality Control / Assurance
Five parts of the program
Internal
External
Flour millers conduct process control and quality
checks
Food control authorities inspect flour mills and
analyze flour samples
This tool kit focuses on the internal quality control with the
assumption that the millers purchased high-quality wheat to meet the
customers’ expectations.
The tool kit also highlights the quality assurance process at external
laboratories.
Internal Quality: Overview
Use these five quality control methods in every mill:
1. Monitor the fortification system regularly
2. Conduct qualitative testing regularly
3. Monitor premix feed rate and flour flow rate
4. Keep records of premix usage and fortified flour
production
5. Submit samples for quantitative testing
Qualitative Flour Testing
Used to:
• Determine if flour sample has
been fortified
• Provide visual estimate of
fortification level
A common qualitative test is the
iron spot test. If iron is detected
by this method, it is assumed
that other nutrients in the premix
are present.
The iron spot test is
formally Method 40-40.01:
Iron Qualitative Method as
approved by the American
Association of Cereal
Chemists (AACC).
Photo by Kate Wheeler.
Iron Spot Test Procedures
These procedures are for ferrous sulfate, ferrous
fumarate and electrolytic iron. See following slides
for modified version when using sodium iron EDTA.
1. Take a sample of fortified flour.
Make an impression in the sample.
2. Add the reagents with a plastic,
disposable dropper.
3. Wait for red spots to appear to
indicate presence of iron.
Iron Spot Test Procedure
4. Compare test with prepared samples or images
such as these to estimate premix addition level
22 ppm
½ treatment
5. Discard sample
44 ppm
Target Treatment
88 ppm
Double Treatment
(ppm = parts per million)
Spot Test for Sodium Iron EDTA
When sodium iron EDTA is used, make two changes to the
iron spot test procedures:
1. In step one, use a larger sample testing surface to make
it easier to observe the smaller quantities of sodium iron
EDTA indicated by red spots
2. In step two, omit hydrogen peroxide as a reagent.
Hydrogen peroxide is used to change other compounds
from ferric to ferrous, but this is not necessary with
sodium iron EDTA. Instead, with sodium iron EDTA,
hydrogen peroxide prevents the color change
Test Responses
• Variability is expected (quantitative test show below)
Feeder Test Results- May 31, 2012
Running Average (N=3)
26.0
Upper
Control
Limit
25.5
g/min
25.0
Target
24.5
24.0
23.5
1
3
5
7
9
11
13
Hour of Day
15
17
19
21
23
Lower
Control
Limit
Iron Spot Test Response
• Make adjustments based on systematic trends over time
established by multiple observations.
• Adjusting a premix addition system based on one or two
spot test results could widen the system variability and
complicate future measurements.
• If 2 out of 5 consecutive samples do not meet
expectations, increase the sampling frequency as
outlined on the next page.
Iron Spot Test Sample Frequency
• If 2 of 5 consecutive samples do not meet the requirements, increase
sampling frequency.
• If the next 2 of 5 samples fail to meet requirements, implement
corrective actions. Verify that the feeder is operating properly then
consider adjusting the:
-
premix feeder control
-
flour transport scales
-
mixing machinery
• If the next 2 out of 5 consecutive sample fail to meet requirements,
stop production until the error is found and corrected.
• Once production restarts, continue frequent sampling.
• Return to normal sampling schedule after 3 consecutive samples are
correct.
Iron Spot Test
Advantages
• Simple, fast, inexpensive
• Requires no sample pre-treatment.
• Requires two or three reagents:
– potassium thiocyanate (KSCN) or sodium thiocyanate (NaSCN)
– hydrochloric acid (HCI)
– Hydrogen perixode (H202), which is not used with sodium iron EDTA
• Food grade NaSCN is available if desired
• Easy: personnel with minimum training can perform this
Limitation
• Not quantitative: does not determine amount of iron in sample.
Qualitative Alternatives to Iron Spot
Test, if Desired
• Ask premix provider for alternatives
• If the premix has riboflavin, use a black light test
– Riboflavin (vitamin B2) will fluoresce under ultraviolet light.
Perform this test in a dark room or box using a wet Pekar slick
to compare fortified with unfortified flour.
• If the premix has vitamin A, use a color test
– Must be done in a laboratory to compare the intensity of color
when vitamin A mixes with copper sulfate.
Record Keeping
Maintaining accurate records is an essential part
of internal monitoring. Develop a system to track:
Flour Ingredient Usage Report
First Shift
Date:
Mill:
Grade
Time
MT Flour
%
%
KG
Premix delivery and usage
•
Flour production
•
Comparison of premix usage with target
needs based on flour production
•
Results of check weighing tests
•
Internal and external quality control testing
results.
Bleach
Malt
Enrichment
Flour Production
•
700 CCN
052 AGU
701 CCN
Beginning Lot #
%
KG
KG
7:00
8:00
9:00
10:00
11:00
12:00
13:00
14:00
Shift Total
0
0
0.00
0.00
Shift Total
MT Flour
0
KG
KG
KG
0.00
0
0
Begin Inventory
Transfer to Mill Floor
0
Total to account for
0
0
0
0
0
0
Closing Inventory
Disappearance
INGREDIENT
Enrichment
Malt
Bleach
NEW LOT #
SUPERVISOR (name):
OPERATOR (name):
START TIME
STOP TIME
These records help the mill assure quality and
may be required during an external inspection.
Internal Quality Control Schedule
1. Check premix feeder hourly. Make sure the speed
detector shows that it is running. Fill hopper if it is low.
2. Run feeder check weights at least every 8 hour shift.
3. Run iron spot tests at least every 8 hour shift.
4. Conduct inventory control of premix usage and fortified
flour production at least quarterly.
Detail the quality control responsibility, frequency, protocol,
and reporting activities in the mill’s quality assurance
manual. Instruct all mill personnel in the procedures.
Assign reporting to someone with authority to act on the
information.
Internal and External Testing
Types of laboratories testing fortified flour
- Quantitative tests.
- Quantitative tests of all added nutrients
- Checks results and procedures of other labs
Government
Laboratory
Reference
Laboratory
Premix
Suppliers
-Certificate of analysis on premix
- Quantitative tests of all added nutrients
- Runs or manages biological testing.
- Audits mills.
Central Milling
Laboratory
Mills
Laboratory/Production Activities
- Fortificant inventory control
- Feeder checks
- Iron spot tests (if applicable)
- Flour sampling
-Runs quantitative tests on
indicator nutrient and other tests
-Audits mills within the company
Quantitative Testing
• Send samples to laboratory using internationally recognized
methods (AACC or ICC and AOAC)
• Requires sophisticated equipment and careful adherence to
protocols due to the small concentration of vitamins and minerals in
a flour mixture.
• If results are suspect, the sample can be submitted to a certified,
reference laboratory for further analysis.
Laboratories running quantitative tests should:
• Make a sample of standardized flour fortified with a certified level of
nutrients as a reference
• Routinely conduct a blind analysis of the reference sample to verify
laboratory procedures
Indicator Nutrient Testing
• One premix ingredient (usually iron) is typically tested
as “indicator” of others. This is valid for premix that has
been properly designed, manufactured and mixed.
• Because the ratio is constant, measuring one nutrients
can verify the delivery of the others.
• Assumes no destruction
or separation of the
indicator nutrient after
the premix was added.
Spectrophotometric test for iron
Creating Composite Samples
A composite sample may be used to estimate the weighted
average nutrient value in a production run. For a composite
sample:
• Take 5 to 10 spot samples representative of a
production lot, such as an 8-hour run
• Collect the same sample size
• Distribute sample collection evenly over the
production time period
Capability Study Guideline
Quantitative testing determines a mill’s ability to produce a uniformly
fortified flour, meeting specifications.
• Collect individual, not composite, flour samples
• Take 7 or more samples over an 8-hour run
• Calculate the coefficient of variation (CV). The CV is the standard
deviation divided by the mean, expressed as a percent
• Identify the analytical error for that lab assay
Example values
Assay
(developed from FFI references)
Assay CV %
Flour Mill Production CV
Iron
13.5
11.3
Folic
10.3
11.7
Thiamine – B1
15.2
10.7
Riboflavin – B2
14.0
11.0
Niacin – B3
14.1
6.2
Control Chart
Feeder Test Results- May 31, 2012
Running Average (N=3)
26.0
Upper
Control
Limit
25.5
g/min
25.0
Target
24.5
24.0
23.5
1
3
5
7
9
11
13
Hour of Day
15
17
19
21
23
Lower
Control
Limit
Government’s Role in Mill Monitoring
Government authorities conduct various roles in flour fortification
monitoring, often including:
• Confirming that technical specifications, process control and quality
procedures and performance records are maintained at the mill,
packaging sites, and points of entry into the country
• Inspecting and verifying legal compliance with the country standard,
based on a quantitative assay
– Samples should contain the fortificant, and at least 80% of
samples should present the legal minimum.
– Less then 20% of the samples should have a nutrient content
above the maximum level, if one has been established.
Plant Audits
• Off-site audit with government official reviewing
information supplied by mills
• On-site audit with government official visiting the mill to
determine if the mill is properly fortifying flour and to
validate data supplied in off-site audits
More Information on Quality
Control / Assurance
Chapter eight of the Guidelines on Food Fortification with
Micronutrients published by the World Health Organization and the
Food and Agricultural Organization of the United Nations
The Flour Fortification Initiative at info@ffinetwork.org