By Wilmer Pacheco, Adam Fahrenholz and Charles Stark
The quality of finished feed is defined by its ability to meet the needs and expectations of the customer. Quality assurance and quality control are terms typically used interchangeably. However, quality assurance is a program of systematic activities which includes policies, procedures and process controls that when implemented provide confidence that a product or service will meet quality requirements at all times. Quality control is a component of a quality assurance program and consists of a series of plant processing measurements to make sure that pre-defined quality parameters are achieved during receiving, processing, and feed delivery. A good quality control program minimizes the likelihood of poor quality products reaching the customer as it focuses on the inspection of ingredients (e.g., mycotoxin, moisture, protein, fat, anti-nutritional factors, etc.) and products (e.g., pellet quality, protein, fat, minerals, etc.) as well as rejection of ingredients or removal of products that don’t comply with established quality standards. Since sampling all the ingredients or finished feeds is unfeasible, the quality control program relies on sampling techniques and frequencies of inspection. If quality is variable, the quality control program becomes more difficult to manage as a higher number of ingredients or feeds needs to be sampled and analyzed to make sure inferior quality ingredients don’t enter the facility or poor quality products don’t leave the facility and enter commerce.
A quality assurance program must address all phases of production from ingredient receiving to loadout, delivery and all the production phases in between. Ingredients used at the feed mill should be purchased from approved suppliers, and employees working in the receiving area should evaluate the condition of the transportation vehicle, and physical quality of grains and feed ingredients. In addition, receiving personnel need to make sure feed ingredients have not been commingled or cross-contaminated with restricted-use mammalian protein. If ingredients are received by rail, each rail car should be inspected to make sure the seals have not been broken prior to unloading. On the other hand, bagged ingredients should be examined to make sure bags have not been torn or broken; additionally, bags should be counted to verify that correct quantity and weight have been delivered. The next step is to take a representative sample following sampling procedures and analyze it according to a pre-established analytical schedule. Ingredient samples should be retained for at least six months after the feed is manufactured and delivered to the buyer or farm. After ingredients are cleared for receiving, the initial discharge from trucks or rail cars should be monitored visually for any evidence of foreign material or foreign objects. An employee should be present during the unloading process to check the condition and quality of ingredients and stop the process if questions regarding quality arise. During grinding, it is important to define particle size specifications, which might change depending on the species for which the feed is intended to be fed. The next step is to determine sampling frequencies, sample location, amount of sample, sample handling, and methodology used for particle size analysis. The use of sieve agitators and/or sieving agents (e.g., silicon dioxide) should be specified with the results of the particle size analysis, since the use of both or either one of them can influence the result of the analysis. Furthermore, during batching it is important to define the monitoring frequency of the calibration of scales and liquid meters, weighing tolerances, and review of batch records. If medicated feed additives are used, it is important to monitor drugs receipts, daily usage, reconciliation, and determine acceptable variance between theoretical and actual usages. If the variance is out of tolerance, it is important to define the steps necessary to retain the product or recall any product that has entered commerce, until the root cause of the problem has been determined and corrective action has been taken to ensure the product is safe to feed to animals. Mixing is important to make sure the animals or pets are receiving all necessary nutrients without any deficiencies or toxicities. Therefore, it is important to define the ingredient addition frequency with possible delays between the opening of major, minor and micro scales, length of dry and wet cycles, mixing sequence, flushing, sequencing, cleaning protocols, batch size depending on ingredients’ density, and frequency of mixer uniformity tests. Many of these parameters can be pre-defined when new formulas are being entered into the system. During thermal processing (conditioning, expanding, pelleting, extrusion), drying, cooling, post pellet liquid applications (PPLA), etc., it is important to define conditioning temperature and retention time during thermal processing, die specifications, bed depth and retention time during cooling, frequency of moisture and temperature monitoring of the finished feed, frequency of calibration of scales and liquid meters among others. If pellet quality falls below the standard, it is important to have an action plan to correct quality issues. Many times, feed mills focus on the physical quality of the pellets but it is equally important to understand the effect of heat processing on the nutrient quality of the finished feed especially when heat sensitive ingredients (enzymes, synthetic amino acids, milk products, etc.) are included in the diets. If possible, a quality assurance program should have a process control person responsible who is constantly visiting different areas of the plant and monitoring the functioning of the equipment and the consistency of a product. The same person can be the liaison between the quality control team and the production team to make sure quality objectives are achieved at all times.
Procedures should be in place to monitor the quality of finished feeds (e.g., nutrient levels, pellet or crumble quality, particle size in mash diets) and to fulfill labeling requirements. It is also important to define the frequency of equipment inspection, loading and unloading protocols, information needed in shipping documents as well as sequencing, flushing, and physical clean out procedures to prevent cross contamination between feeds. The adequate functioning of scales becomes crucial when using bags for the feed; therefore, all used scales should have calibration records and lot number identification and comply with labeling requirements, inventory rotation and warehouse managements. Recently, the usage of QR and bar codes in bagged feeds has made inventory management more efficient. In addition, these tools have improved product traceability during feed transportation from warehouse to the customers.
Product traceability and recalls should also be part of a quality assurance program to investigate and address customer complaints, discrepancies between formulated and analyzed nutrients, and to recall products if safety has been compromised. Finally, the training of new employees should also be part of a quality management program. Employees should be trained to make sure the quality program is being implemented correctly and the quality assurance team should provide feedback if adjustments are needed to address quality concerns. New employees should understand the importance of a quality program in their specific areas and how quality control plays a role in the overall quality assurance program. A quality control program without quality assurance can be expensive for a feed mill; however, if both are developed and implemented appropriately, they will have a positive effect on the quality of the finished products, the image of the company and its bottom line.