How to prevent cross contamination in feed?
Due to the lagging behind of China's feed standard system construction, many operation technology specifications have not yet been established, and there is a lack of authoritative and versatile methods for the inspection of feed additives and illicit drugs. Therefore, for most of the feed manufacturers in China, it is imperative to establish a set of effective measures and methods for the safety of feed.
The drug added to the target feed for a certain purpose, in the process of processing, appears in the non target feed for a variety of reasons, that is, cross contamination. The cross contamination of feed exists in all feed plants. Reducing the cross contamination of feed is an important measure to ensure the safety of feed. From the point of view of feed processing, the author analyzes the causes of drug cross contamination, and puts forward some suggestions for improvement for the reference of the feed producers.
Analysis on the cause of pollution in 1 feed processing
The drug contamination of feed may occur in the process of feed processing, transport and storage. Among them, the main pollution in the process is as follows:
1.1, the dust collecting system is distributed in the processing workshop of large and medium-sized feed plants, and the dust collecting system is distributed in every key part of the processing. The purpose is to reduce the dust produced by processing links and purify the production environment. Considering the economic consideration of the collected dust, it is usually returned to feed. However, the delayed dust fall or the unreasonable design of dust collection system can lead to the excessive absorption of drug additives.
The accurate proportioning of the 1.2 ingredient system is the prerequisite and guarantee for the strict implementation of the production formula. Once the measurement of drug additives is wrong and has not been found in time, the follow-up section is irreparable and will bring serious pollution.
The mixing process of 1.3 mixed system is the process of making all kinds of ingredients evenly distributed, and it is also the main link to produce drug pollution. The reason is: the mixing time setting is not reasonable, did not reach the expected effect of mixed, mixed uneven or excessive mixing phenomenon; improper mixing machine design, resulting in incomplete discharge, residual feed; mixer outlet closed or pad damage to material leakage; feed viscosity (due to the addition of molasses and oil) or by electrostatic and attached on the inner wall, top mixing machine and air return pipe.
The 1.4 buffer storehouse is to balance the processing capacity between the equipment to facilitate the continuous production of equipment. However, if the buffer volume is too small, the design is not reasonable, or because of static or wet attachment, it can not completely remove residual feed, and also can cause drug contamination.
1.5, the conveying distance is too long, the design or operation of horizontal conveying equipment is unreasonable, the bottom clearance is too large, and the attachment of feed due to static electricity or moisture can cause feed residue.
The bucket elevator of the 1.6 bucket elevator usually has few drug residues, but static electricity, humidity and viscosity are too large, which will cause residue on the lifting bucket or base, resulting in pollution.
1.7 the drug pollution caused by the silo is mainly caused by unreasonable design or operation (the slope is less than 60 degrees). In addition, the internal fluctuation of the silo, the incomplete clearance of the silo, the alternate use of the same silo containing medicine and non drug containing feed can cause the contamination of the feed drugs.
1.8 sequencing production scheduling is arranged in order to produce different types or different formula feed. Due to operation technology, production technology, production equipment and other reasons, the batch feed products will have an impact on the subsequent production, so incorrect production sequencing is also the cause of drug contamination.
2 how to reduce or prevent pollution in processing
The pollution can be significantly reduced by modifying the production order or adjusting the mechanical equipment. For some manufacturers, it is possible to repair and replace mechanical equipment, or even to refurbishment of the whole production system. The measures to reduce drug pollution are mainly in the following aspects:
2.1, when designing feed processing technology, we should shorten transportation distance as far as possible, and use horizontal conveyance devices as much as possible, and distribute distributor and self flow as far as possible. For horizontal conveying equipment, a scraper conveyor with automatic clearance function should be used as much as possible. Under the conditions of meeting the requirements of the process, the number of lifting times and the number of transition hopper are minimized. Dust suction system as soon as possible to set up an independent network. The adding of the compound premixture is arranged in the upper part of the mixer as far as possible.
2.2 feed production scheduling general principle is the first production of free drugs, diet, reproduction of the drug containing feed; adding a drug in the same animal feed or feed used should be arranged in a first processing and processing together, high content of feed, feed processing with low dose; drug feed containing the same animal use, production is not affected by the withdrawal period limit feed, such as lactating sows (pre) feed, reproduction by withdrawal limit feed; there is a medicated feed sales is much higher than that of non medicated feed, can consider setting up a complete separation of the special production line, with the possibility of to minimize cross contamination. The reasonable ordering should be embodied in the whole processing system, that is, from the comminuted storehouse to the end of the finished warehouse.
2.3, electrostatic attachment can eliminate static electricity, install ground wire on equipment, purchase non electrostatic premix, add liquid raw materials to control dust and reduce static electricity, and install oscillators on the location of easy to feed feed to shake down attachments.
The air flow rate of 2.4 dust collecting system design and network flow pressure, and promptly clean up dust in the system; the liquid material to reduce dust; dust collection should be abandoned in the process of producing drug feed containing, or similar to the next batch of drug containing playback