1. Quality Control / Assurance Internal Quality Overview
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

2. 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
Gains customer satisfaction
Adheres to government regulations
Ramadan Deliu, Head of Laboratory at M & Sillosi Milling Company, prepares flour for an iron spot test. Photo by Kate Wheeler.

3. Quality Control / Assurance
Five parts of the program
Internal
Flour millers conduct process control and quality checks
External
Food control authorities inspect flour mills and analyze flour samples
Commercial
Inspectors check fortified products at retail stores
Intake
Household surveys confirm consumption
Impact
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
A quality control and quality assurance program has five parts as noted here.

4. Quality Control / Assurance
Five parts of the program
Internal
Flour millers conduct process control and quality checks
External
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.
Flour millers are responsible for the first one; they play a role in the second.
Note that nothing added during fortification will improve the mixing and baking performance of poor quality wheat. The first step to quality is to choose high quality wheat.

5. Internal Quality: Overview
Use these five quality control methods in every mill:
Monitor the fortification system regularly
Conduct qualitative testing regularly
Monitor premix feed rate and flour flow rate
Keep records of premix usage and fortified flour production
Submit samples for quantitative testing

6. 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 : Iron Qualitative Method as approved by the American Association of Cereal Chemists (AACC).
Photo by Kate Wheeler.

7. Iron Spot Test Procedure
Take a sample of fortified flour. Make an impression in the sample.
Add the reagents with a plastic, disposable dropper.
Wait for red spots to appear to indicate presence of iron.
First three steps of iron spot test

8. Iron Spot Test Procedure
Compare test with prepared samples or images such as the one below to estimate premix addition level
Discard sample
22 ppm
½ treatment
44 ppm
Target Treatment
88 ppm
Double Treatment
Steps 4 and 5 of iron spot test.
ppm = parts per million

9. Spot Test for Sodium Iron EDTA
When sodium iron EDTA is used, make two changes to the iron spot test procedures:
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
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
If flour is fortified with sodium iron EDTA, the iron spot test needs to be modified slightly.
Electrolytic, sulphate or fumarate iron sources are ferrous ions which are converted to ferric ions though the addition of hydrogen peroxide.
Sodium iron EDTA is already a ferric ion, so adding hydrogen peroxide is not necessary for the conversion. Using hydrogen peroxide would prevent the color change and make the test useless.

10. Test Responses Variability is expected (quantitative test show below)
Upper
Control
Limit
Target
Each blue point on the graph represents an average of three weigh-off values in grams per minute. This shows that the running average is centered at about the target level, represented by the red dashed line.
Lower
Control
Limit

11. 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.

12. 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.

13. 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

14. 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.

15. Record Keeping
Maintaining accurate records is an essential part of internal monitoring. Develop a system to track:
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.
These records help the mill assure quality and may be required during an external inspection.

16. Internal Quality Control Schedule
Check premix feeder hourly. Make sure the speed detector shows that it is running. Fill hopper if it is low.
Run feeder check weights at least every 8 hour shift.
Run iron spot tests at least every 8 hour shift.
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.

17. Internal and External Testing
Types of laboratories testing fortified flour
- Quantitative tests of all added nutrients
- Checks results and procedures of other labs
- Quantitative tests.
- Runs or manages biological testing.
- Audits mills.
Certificate of analysis on premix
Quantitative tests of all added nutrients
Runs quantitative tests on indicator nutrient and other tests
-Audits mills within the company
Mills
Laboratory/Production Activities
- Fortificant inventory control
- Feeder checks
- Iron spot tests (if applicable)
- Flour sampling

18. 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

19. 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

20. 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

21. Capability Study Guideline
Mills may seek external quantitative testing to determine their 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
Assay Error
Acceptable CV
4.9% or less
20% %
35% %
45%
Guidelines developed from FFI references

22. Control Chart Upper Control Limit Target Lower Control Limit
Control chart is established based on capability of the process. Upper and lower control limits reflect the range of operation of the processing system. They should be within the limits established by country regulations, or at least stay within good manufacturing regulations.
As with internal testing, mills should not adjust addition rates based on the results of a single analysis.
Base changes in premix addition rate or premix formulas on trends seen over time.
This is best seen by plotting a standard control chart as indicated below.
Lower
Control
Limit

23. 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.

24. 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

25. 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 Food Fortification Initiative at