It is possible that mildew can occur in any part of the process of preventing mildew from the acceptance of raw materials to the finished product processing. The following are the factors that may cause mildew and the measures that need to be taken:
1. Acceptance and warehousing of raw materials:
Raw materials are the basis of product quality, and serious feed quality problems are almost always related to raw materials. So in the acceptance of raw material storage and warehousing link need to prepare for the following work: before purchasing raw materials, in addition to detecting the nutritional indexes, also should control the moisture of raw materials, microbial indicators and the variety of insects.
1. Water is one of the most important influencing factors for mold growth and reproduction. In general, the moisture content of primary ecological grains such as corn and wheat should not be higher than 14%. Soybean, bran, soybean meal and other water should be less than 13%; The moisture content of cotton meal and vegetable meal should be less than 12%. The raw material of excessive moisture is not resistant to storage, easy to mold. In the process of feeding, we should also pay attention to the raw material condition (because of the process defects of the manufacturer, the local moisture content is often caused to produce clumps and mildew).
Measures: we can check whether the total number of molds in the raw materials exceeds the standard. For enterprises without conditions for mold testing, the production date, production process and storage conditions of raw materials can be understood. Observe whether the color appearance of raw materials is normal and whether there is a cluster phenomenon; Use smell to determine whether the raw smell of raw materials is normal or not. Use the hand or thermometer to determine whether the raw material has a fever and other measures to determine whether the raw material has mildew.
2, insects in the summer is not only a loss of some raw material storage to increase the direct cause of, and they are in the process of growth, reproduction and migration of metabolites will be seriously polluted raw materials (corn, wheat). What's more, the activity of the cang worm causes the raw material to heat up, which causes the growth and development of microorganisms, causing or accelerating the mildew. In moist and warm environment, mites usually multiply in grain, feed and in transportation and processing equipment, which can easily cause mildew. The growth of mites in feed has become one of the reasons for customers to complain about the feed of processing plant. Moisture, temperature and air relative humidity are the main factors that affect the reproduction of mold and cang. When the raw materials are stored in the warehouse, they should be divided according to different varieties and batches. The grain stack should not be too high, and the distance between the pile and the wall, the pile and the pile should be about 20-1250px. In summer, according to the weather conditions, the warehouse will be drained of wind, heat dissipation. Repair the damage in the warehouse in time to prevent leakage and seepage.
The use of raw materials in principle "advanced first out" can also be used according to the moisture of the raw materials and the degree of mold contamination. If the warehouse condition is poor, should not store too much raw material, and should be purchased with the principle of "fast forward out", use raw materials. At the same time, it will strengthen the clean and hygienic management of the warehouse, clean and dispose the raw materials and the floating dust of the loading and unloading process in a timely manner, so as to prevent the overlaying of the ground, moisture and mildew, or the breeding of canisters; For mildewed raw materials, should be transferred as soon as possible to avoid becoming a mold pollution source and infect other raw materials.
Ii. Production process:
The production process may lead to mildew mainly because of excessive moisture in the finished product. Excessive moisture content is divided into average moisture and local moisture. The reasons for the excessive moisture content of finished products are complicated, which can be summarized as follows:
1. Average moisture content of finished products:
Feed in the process of production due to its high moisture, raw material drying or cooling system failure finished average excess moisture causing the phenomenon of early feed mildew is generally less, because the product of the average moisture content by detecting if overweight will be after processing, will not flow into the market. (if production and quality control are not well controlled, such problems will arise.) However, in the process of small batch production, the granulation temperature has not been adjusted to normal. When the particles leave the ring mold, the temperature is low and the temperature in the cooler is low. The water molecules in the feed are weak and not easy to distribute. In addition to the thin layer in the cooler, the resistance of air flow is large, and the temperature of feed is rapidly reduced to room temperature when cooling, but the water is not released, causing excessive moisture.
Rework treatment of this material (in the condition of low temperature and relative humidity) is difficult to reduce water to a qualified level if it is not matched with low water raw materials or increased bulk. This kind of material stock time is long after easy mildew metamorphism. The solution can be obtained from several aspects :(1) controlling the moisture of raw materials (the mixed raw material moisture is 12%-14% in summer and 10%-11.5% in winter); (2) the enlarge production batch, according to different specifications of the granulator and cooler to determine the minimum safety production batch, in terms of pelletizer is the smallest safety production batch after tempering temperature to normal, have granulating of 25% of the total quantity is smaller than the number of (and before tempering temperature is not reached 50 ℃ of the particles to pick out); For the cooler, the minimum safe production batch is the whole batch of material in the cooler for more than 60% of its capacity. (3) before the granulating machine is started, the water in the steam pipeline should be drained. And always check whether the pipeline's water valve is normal. (4) by adjusting the equipment and process parameters such as conditioning heat preservation, improve the steam saturation, increasing tempering temperature, the control of the pelletizer feeding capacity is to extend the time of particles in the ring die (in order to improve the temperature of the particles leave the ring die), raise the level height of the cooler, select reasonable throttle opening and so on measures to control the finished water within a certain scope.
2. Excessive moisture in the finished product.
There is a certain concealment of local moisture content and difficult to control. It is the main cause of mildew caused by excessive moisture content. According to the long-term observation, the following situations can lead to excessive moisture content in the feed.
(1) state of equipment technology and production operations are no problem, the raw material initial moisture also meet the requirements but each batch of raw materials at the beginning because of the low tempering temperature, the steam pipeline to deposit a certain amount of condensed water so make the grain moisture content is higher, the temperature is low, coupled with the cooler temperature and lower the activity of water molecules is poor, not easy to send out. After cooling, the moisture content of this part is often exceeded. Solution: before production to clean steam system of condensed water, granulator material must pick out which just came out, not into the cooler until when the tempering temperature of 50 ℃ to import cooler. The material should be processed with 2-4 packets of material at the beginning of each batch.
(2) equipment adjustment is not reasonable or equipment fault: the cooler is not reasonable or the location switch fault, and during the production process, the material leakage is not fully cooled and dry. These materials will produce mildew in a short period of time, and its expression is sporadic mildew, and continuously develop into a large area of mildew, raw insects and fever. The solution is: a, select the sensitive and reliable "material position sensor" and the positioning switch; B. The height of the "material locator" cannot be set too high; C. Adjust the air door opening of the fan and control the outlet negative pressure of the cooler; D, the Angle of the turning plate of the cooler or the overlap of the fence should be adjusted so that the ventilation area can not be too narrow and the leakage in the production process should be avoided.
(3) the internal load of the cooler is not uniform: the loose material of the cooler, the uneven material of the fabric, or the insufficient air area due to the mesh of the individual cooler. The cooling time and the cooling intensity of the feed in the cooler are not uniform. Partial heat and moisture exchange is not sufficient, excessive moisture content. In subsequent storage there is sporadic mildew. The solution is to clean up the feed that is plugged in the sieve through the Angle of the dispenser, the cloth feeder and the flap, and the cooling time and the cooling intensity of the feed in the cooler are consistent.
(4) the pelletizer and cooler "rice crust material caused by mildew:" in the process of production the ring die pelletizer cover, granulator discharge chute, a corner of the cooler will be adsorbed on a large number of high moisture "rice crust material", their adsorption to a certain thickness will fall into the feed. Because of this "rice crust material" in the process of formation at high temperature, high humidity environment, starch gelatinization degree is very high and deep color, have created favorable conditions for mold reproduction, they had already gone mouldy before falling into the feed. After cooling with the feed, the water remains as high as 15% to 25%. These "rice crust material" through some transportation equipment and sizing screen will burst into large and small irregular mass, these large block of material can't through the upper deck of the sizing screen mesh by as debris removal, including smaller block material through the sizing screen screen mesh upper mixed with feed. These musty, high water masses can easily induce the mildew of surrounding fodder particles. The solution is to remove the "crib" on the equipment, such as the ring mould cover of the granulator, the feeding tube of the granulator, the dead Angle of the cooler, etc., so as to avoid the accumulation of it into the feed.
(5) packaging of finished products: if the packaging bag cannot be moisture-proof, the feed will absorb moisture in the storage, and the moisture will rise after the moisture absorption, and it will be prone to mildew. In the summer, it is common to complain that the feed has mildew, fever, and worms in the feed of the customer's house for about 35 days. For the finished packaging, one is that the inner and outer bags of the packaging bags are intact, and the second is that the storage time of the customer should be controlled in about 30 days.
Iii. Storage and transportation links of feed finished products:
Feed in storage and transportation link, if be affected with damp be affected with damp is typically produce scattered mould first, (if the feed water soaked group that can produce a dark colored fever agglomerate, found that a large number of insects around the agglomerate. If feed to sunlight exposure, will feed in the water, and sunshine temperature down, after the water vapor on the lining of the product into water droplets, these droplets after being absorbed by the surrounding feed caused local excess moisture, cause sporadic mildew). Therefore, in the storage and transportation links, ensure that the packing bags are sealed and the environment is dry, so that the feed is not damp, the water is soaked and the sun is exposed to the sun.