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
Quality Control / Assurance
Quality Control / Assurance
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
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.
Iron Spot Test Procedures
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.
4.Compare test with prepared samples or images such as these to estimate premix addition level
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
Variability is expected (quantitative test show below)
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
•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
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
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.
Maintaining accurate records is an essential part of internal monitoring. Develop a system to track:
Premix delivery and usage
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.
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
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.
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
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.
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
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