Drug contamination during feed processing refers to a certain amount of drug or drug-containing feed remaining in a certain equipment during the processing process, which is then mixed into the next batch (or even several batches) of feed, that is, the residual drug (or drug-containing feed). ) caused contamination of the next batch of feed.
1 Analysis of the causes of pollution during feed processing
Drug contamination of feed may occur during feed processing, transportation and storage. But the processing is mainly in the following aspects.
1.1 Vacuum system
In the processing workshops of large and medium-sized feed factories, the dust collection system is distributed in each main link in the processing process, the purpose is to reduce the dust generated in the processing link, purify the production environment and reduce the risk of dust explosion. For the collected dust, from economical considerations, it is generally returned to the feed, but the dust is delayed to return to the same batch of feed, or the design of the dust collection system is unreasonable, resulting in excessive absorption of drugs and excipients Or into the next batch of dust due to static electricity or moisture adhered to the dust collection system.
1.2 Batching system
Accurate ingredients are the premise and guarantee for the strict implementation of the production formula, especially the accurate measurement of pharmaceutical additives that have a direct impact on feed safety is very critical.
1.3 Mixer system
The mixing process is the process of uniform distribution of various components, and it is also the main link of drug contamination. The main reason is that the unreasonable setting of the mixing time does not achieve the expected mixing effect, resulting in uneven mixing or excessive mixing; improper design and construction in the horizontal mixer, mixing the spiral belt (or paddle) and the mixer The gap between the inner wall and the bottom is too large, resulting in incomplete discharge and residual feed. Vertical mixers are often left in the spiral pipe or bin wall under the discharge port and cannot be discharged. The material port of the mixer cannot be tightly closed or the gasket is damaged, causing material leakage. In addition, the feed with high viscosity (adding molasses and grease) adheres to the inner wall of the mixer, or electrostatically attaches to the inner wall, top and air return pipe of the mixer.
1.4 Buffer bin
The buffer bin is to balance the processing capacity between the equipment, which is beneficial to the production of continuous equipment, but it is too shallow or too small in volume, poorly designed, or attached due to static electricity or moisture, and cannot completely remove the residual feed, resulting in drug contamination.
1.5 Conveyor
Long conveying distance and excessive use of horizontal conveying equipment may cause residual pollution. The main reason is that the horizontal conveying equipment is poorly designed or constructed, the bottom gap is too large to accumulate feed, or it is not completely cleaned and adhered due to static electricity or moisture.
1.6 Bucket elevator
The residual drug caused by the bucket elevator is generally very small, but the feed is attached to the residual bucket or base due to static electricity, humidity and viscosity, etc., which can also cause pollution.
1.7 Silo
The drug pollution caused by the silo is mainly caused by poor design or construction (slope less than 60 degrees). In addition, frequent beating leads to uneven internal, resulting in bridging and adhesion. In addition, the removal of feed is incomplete and residual feed is used. The same bin is used alternately for medicated and non-medicated feed, resulting in feed drug contamination.
1.8 Processing order
The processing sequence is to successively arrange the production of different types or different formulas of feeds under the condition of the existing processing equipment. Due to reasons such as operation, production technology, production equipment, etc., the feed products produced in the previous batch will definitely have an impact on the products produced later. Therefore, incorrect production sequencing is also the cause of feed drug contamination.