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Section 5 Quality Control / Assurance Ø Internal Quality Overview Ø Qualitative Testing, including iron spot test procedures Ø Record Keeping and Quality Control Schedule Ø Quantitative Testing and Composite Samples Ø Government’s Role In Monitoring
Quality Control / Assurance Ramadan Deliu, Head of Laboratory at M & Sillosi Milling Company, prepares flour for an iron spot test. Photo by Kate Wheeler. 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 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 Procedure 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 the one below to estimate premix addition level 22 ppm ½ treatment 44 ppm Target Treatment 5. Discard sample 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. . . 26. 0 Upper Control Limit 25. 5 g/min 25. 0 24. 5 Target 24. 0 23. 5 23. 0 22. 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: o premix feeder control o flour transport scales o 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: o potassium thiocyanate (KSCN) or sodium thiocyanate (Na. SCN) o hydrochloric acid (HCI) o Hydrogen perixode (H 202), which is not used with sodium iron EDTA • Food grade Na. SCN 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 o Riboflavin (vitamin B 2) 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 o 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: • 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.
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 of all added nutrients - Checks results and procedures of other labs - Runs or manages biological testing. - Audits mills. -Runs quantitative tests on indicator nutrient and other tests -Audits mills within the company -Certificate of analysis on premix - Quantitative tests of all added nutrients Mills Laboratory/Production Activities - Fortificant inventory control - Feeder checks - Iron spot tests (if applicable) - Flour sampling
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 sample size • Distribute sample collection evenly over the production time period
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% 5 - 9. 9% 35% 10 - 15% 45% Guidelines developed from FFI references
Control Chart Feeder Test Results- May 31, 2012 Running Average. . . 26. 0 Upper Control Limit 25. 5 g/min 25. 0 24. 5 Target 24. 0 23. 5 23. 0 22. 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 o Samples should contain the fortificant, and at least 80% of samples should present the legal minimum. o 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 Food Fortification Initiative at [email protected] org