Title page for ETD etd-03092005-103146

Document Type Master's Dissertation
Author Van Rooyen, R S
URN etd-03092005-103146
Document Title Improved pellet quality following the implementation of a HACCP system in a commercial animal feed pelleting plant
Degree MSc (Production Animal Studies)
Department Production Animal Studies
Advisor Name Title
Dr W Schultheiss Committee Chair
Dr H Kster Committee Co-Chair
Prof B Gummow Committee Co-Chair
  • no key words available
Date 2003-10-09
Availability unrestricted
An investigation of complaints about the cause of poor product quality and performance pointed to critical control points (CCPs) in the pelleting process that were either absent or not monitored and controlled. The non-conformance cost due to poor pellet quality and product inconsistency is quite significant.

The positive relationship between pellet quality and animal performance is well known. Poor and inconsistent quality of pelleted feed is the consequence of many contributing factors such as formulation, processing variables, people and the manufacturing environment, which affect pellet quality either individually or in combination.

Data collected on the control of some critical elements in the production process revealed that many production parameters are often not closely monitored or controlled, and that quality control limits are often poorly enforced or non-existent, explaining the varying causes for complaints on the quality and inconsistency of pelleted feed.

Production facilities differ in layout and the success of a Hazard Analysis Critical Control Point (HACCP) program exists in its systematic method of process analysis, applying appropriate risk controls and timely corrective protocols. Modified HACCP programs can be utilized to reduce process parameter variation resulting in improved product quality and consistency.

A HACCP system modified for the pelleting environment was used as an intervention tool to address poor pellet quality and product inconsistency in a broiler feed mill. Implementation of the system was achieved by measuring the quality and variability of products and processes prior to implementation. The processing layout was identified, analysed, CCPs and limits set after which the CCPs were measured and compared to ideal targets. Corrective actions and changes to the production process were prioritised in order of each CCPs contribution to pellet quality. Monitoring, control and corrective protocols were introduced for CCPs through consecutive training and work sessions. Re-assessment of the pellet quality and product variation concluded the intervention phase.

Data analysed from the first phase helped to facilitate the restructuring of the production process and the implementation of improvement phases. Systematic analysis identified formulation (fat addition levels and point of addition) and mash grinding fraction as key areas of improvement. This was achieved by lowering the fat percentage in the mixer from 3.50 to 0.5%, thereafter adding the fat by means of a post pelleting fat coater. The coarse pre-pelleting mash fraction (particle size being above 2360mm), was reduced from 28.5 to 1% on average and the ideal target particle size (being from 600mm to 1440mm), was increased from 20.5 to 51% on average. This increase was achieved by correcting and improving grinding operation with a larger capacity hammermill. Conditioning temperature increased from 64.5 to 74.5oC. Correcting the above changes to critical factors contributed to increasing the pellet percentage of the final product at loading from 63.05 to 86.18%.

Improved monitoring of CCPs and timely corrective protocols led to a further improvement in loaded pellet percentage from 86 to 90% and also improved the repeatability in obtaining better pellet quality at loading. The STDEV of the final product pellet percentage showed an improvement of 13.3 to 5.39. Hazard analysis and the collection of data helped in identifying further areas of improvement.

In conclusion, the HACCP system as implemented in this plant, resulted in the improvement of pellet quality (percentage of pellets at loading and pellet durability) as well as a reduction in its variability. It is recommended that HACCP systems should be used more pro-actively as a quality assurance tool for process improvement, assuring product safety, reducing process variation and increasing product quality.

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