FBA Issue 34: September / October 2010
Steam heat treatment systems for feed mash
In Europe an increasing number of countries around the world, livestock diets are changed. The trend is towards coarser feed structures, as they have been found to improve feed conversion ratios, thereby making them both more efficient and cost-effective.
In context of this trend's advantages, we believe that the Forberg® Steam Heat Treatment System is the answer to these rising, emergent feed industry requirements.
When done intelligently and with precision, steam heat treatment combines efficiency, high feed quality and microbe-free hygiene with the ability to add thermally sensitive additives during the latter stages of processing.
Mixing efficiency has always been and always will be, an essential core process for both feed and food manufacturing. In this respect, the twin-shaft paddle mixer is a versatile machine, with which many processes beyond mixing can be performed. Below, we focus on further development of feed making processes, in close cooperation with customers and research institutions.
Steam heat treatment of mash feed
In the field of poultry feed for layers, the importance of mash conditioning has been a new development.
For a number of reasons, today's most common poultry feed is pelletized, crumbled feed. Nonetheless, we find that mash's superior nutritional qualities are optimized through steam treatment There are several possible reasons for using this state of affairs.
For instance, broilers do need as high as possible energy input in as short a possible time. Traditionally, pelletized feed is cooked and sanitised. This made it an efficient and secure nutrient source for the birds. Finally, food regulations and the industry are based on established technology.
Going forward however, mash feed is now getting more widely used, mainly for layers. For layers, mash feed has several advantages. They are gained by using more time to eat. Moreover, mash feed's tructure is more natural, thereby encouraging better gut development and nutrient absorption.
With respect to creating mash feed, steam treatment can play a central role. Though the use of mash feed is mainly restricted to layers, mash feed in general makes for a more natural nutrient source than pelleted feed.
By applying steam treatment, mash making technology offers the possibility to heat treat large amounts of feed materials without taking a wasteful detour through a pelleting press and milling down pellets later on. The steam treatment of mash is more economical and made even more so in the final steps, since the cooling of pellets is less efficient due to their poor heat transfer rate qualities.
Below, we describe the steam treatment process and its advantages over other types of feed making.
Steam treatment briefly described
In the first step of the process the conditioner/mixer is charged with the feed, which has to be treated. The feeding can take place out of single bin or different components or can be mixed via the Forberg® high speed mixing process.
Next, steam is injected into the mixer to heat up the product to the desired temperature. Then, the temperature is maintained a this high level for a certain period of time, with a view to eliminating pathogens such as salmonella and other potentially dangerous micro-organisms.
In this stage of the process, with temperature and pressure at high levels, liquids which are not initially hygienic, such as molasses for example can be treated as well. After steam heat treatment has been performed, the mixer discharges directly into a dryer/cooler.
During this time, the mixer and the chutes are heated to a temperature that exceeds the dew point on all surfaces As soon as the dryer charged, the conditioner can already produce the next batch.
Within the dryer, the first step consists of warm air being introduced to extract some moisture from the product. In the second step ambient air is blown in to reduce the product's temperature further. After the product has reached the desired temperature and moisture content, heat-sensitive additives such as vitamins, enzymes, flavours and pharmaceuticals can be added. Such additives can be applied in either powder or liquid form.
Advantages
As implied by the above described steps, steam heat treatment is designed as a batch system. It makes it possible to dose exactly and to achieve the correct recipe, hence allowing for precise control over the mash feed's nutritional value. In addition, it gives full control of the process and guarantee that the product will be uniformly treated.
The main advantages of steam heat treatment include the following:
Destruction of salmonella & other pathogens: The product is made pathogen free feed by the destruction of bacteria and reduction in the number of bacterial spores in the mash
Production of feed with course structure: Generally, using a roller mill on mash feed gives good results.
Good nutrient characteristics: The resulting mash feed's nutritional value ideally meets the requirement of the layers
Less nutrient loss: This arises from the preservation of thermo-sensitive nutritional components during production process
Minimal loss of feed material: This is due to the fact that there is very little generation of fines.
Unchanged, consistent feed structure: No fibres are destroyed during the treatment due to the gentle mixing in the twin shaft mixer. Because of steam-induced gelatinisation and micro agglomeration, the end product has improved flow properties compared to traditional mash feed.
Superior mixing: To create feed with optimum nutritional value, mixing plays an important role. With steam heat treatment, feed is always perfectly mixed. The danger of de-mixing is thereby reduced, and can be reduced further by the spraying of oil. All this makes additional pre- and post steam heat treatment mixing installations unnecessary.
Efficient inclusion of additives: A modern mixer with mixing quality CV < 5 makes over-dosing of "minor ingredients" unnecessary. There is no danger for quality degradation of ingredients. At the same time, the steam heat treatment system is a very flexible medium where the adding of vitamins and other thermo-sensitive products can take place. More oil or fat can be added to the mash feed compared to pelleted feed. Spraying of acid in order to prevent further bacterial growth is also possible.
The above are excerpts, full versions are only available in FEED Business Asia. For subscriptions enquiries, e-mail membership@efeedlink.com
