Category Archives: Extruded Soya-Bean

How pet food is made

Pet food can be made in many different ways but the extrusion process remains the most common and was adapted from the process of making breakfast cereals back in the 1950s.

Dry Pet Food Process

  1. Ingredients are brought together in a mixer. Dry ingredients may be ground prior to incorporation with wet ingredients. Once mixed together, they form a moist dough.
  2. The dough is heated in the preconditioner prior to introduction to the extruder.
  3. The extruder, similar to a giant meat grinder that is heated, is where the primary cooking phase for dry extruded pet food products occurs. The dough is cooked under intense heat and pressure as it moves toward the open end of the extruder. At the end of the extruder, hot dough passes through a shaping die and knife (similar to the action of a meat grinder) where the small pieces expand rapidly into kibble once they are under standard air pressure.
  4. Kibble is dried in an oven until its moisture content is low enough to make it shelf stable like a cookie or cracker.
  5. The drying oven is followed by a cooling phase.
  6. After cooling, kibble may pass through a machine that sprays on a coating, which is generally a flavour enhancer.
  7. Packaging (bags, boxes, pouches, etc.) is filled during the last step to precise amounts to meet the weight advertised on the label. The final result is finished pet foods or treats.

We are masters at what we do at Quadro Alloys Trading Enterprise. Remember to contact us for any reason whatsoever, whether it be for information or a quote.


Everyday extruded items?

The BraaiIn a previous article I mentioned that extrusion was a modern day miracle invention and I named a few very general uses. In this article I wish to give you a few more specific everyday examples of the things we use that have been through this process.

Consider this; you are invited to a braai/barbeque, you take your meat, some savoury snacks, a packet of biscuits, some sweets for the children and your cooler box filled with your ice and drinks. Your friend, who is the host at this party, puts the briquettes on top of the already lit firelighters (in the Webber kettle braai) and gets the fire started.

The women start buttering the rolls and preparing the salads, to keep them lovely and fresh they cover them with cling wrap and tin foil.

It may be surprising to know that many of these items have been extruded; the burger patties, boerewors and any vegetarian alternative, your savoury snacks; Niknaks, Doritos, etc., pretty much all your biscuits, your sweets; liquorish and hard candy, the cooler box, the glass for the drinks, the briquettes, the firelighters and the Webber braai, the bread rolls are made from milled maize (flour) and have been buttered with extruded margarine, the pasta, the cling wrap and even the tin foil have all been extruded.

That’s a pretty impressive list of things you could make with our machinery don’t you think?

If you can think it, then it’s probably been extruded! Believe it!

Contact us if you would like a quote or even if you just want more information!

Extruders? What are they and what are they used for?

Huh?It has come to my attention that not many people know what an extruder is and what it’s used for. Let’s hope I can address this injustice in this article!

Extruders are used to create objects of a specified length or size, this process is known as extrusion. Commonly extruded materials would be metals, polymers, ceramics, concrete and even food.

At Quadro Alloys Trading Enterprise we specialize in the design, manufacture and maintenance of extruder units/machines used in food extrusion; the process whereby a specific set of ingredients are mixed together and forced through a large, rotating screw which is tightly fitted inside a stationary barrel and then through a perforated plate or die, the resultant mix is known as the extrudate.

The end product can be anything from fish pellets to dog food.

I mentioned earlier that not knowing all of this was an injustice, well, here’s what I mean: In Africa (and some other countries) poverty is an issue that affects health conditions; some are struggling with malnutrition and some even die from it. Our extruders (in conjunction with our hammer mill machine) can be used to help solve this problem; the soya bean, a legume native to East Asia, is an amazing source of cheap protein used for things like oil, meal, flour, infant formula, dietary (meat and dairy) extenders or substitutes and cattle feed. In addition to these, floating fish feed (something we specialize in and are especially proud of) is often used in feeding the “water chicken”, a species of fish called the Tilapia (which is easily farmed). This fish has now become an accepted mechanism used for the feeding of the poor which is probably one of the easiest ways to feed them – and our philosophy is “feed the fish, feed the poor”.

Extruder machines are miracle inventions, and with your help as an entrepreneur, we can work together and make a difference in this world.


Extrusion temperature: 
A critical control point in pet food processing

The cooking extrusion process, specifically extrusion temperature, is often chosen as a critical control point in food safety HACCP programmes. Many reports describe thermal treatments and their effectiveness; however, no scientific publications exist that demonstrate the correlation of pet food extrusion temperature with control and reduction of Salmonella or a suitable surrogate. Results of recent studies indicate a correlation between extrusion temperature and moisture and the destruction of pathogenic organisms in an inoculated pet food recipe.

By Galen J. Rokey, process technology manager, and Doug Baldwin, director of business development, Wenger Manufacturing

Pet food safety is critical not only because it is the law but is also the responsibility of the pet food manufacturer to maintain a safe food supply. The cost of producing safe products is increasing; however the incremental cost is small compared to the value of one individual becoming ill or dying due to unsafe food or handling practices. A good pet food safety programme can serve benefits including:

1) Reduced risks
2) Decreased waste, shrinkage, and customer complaints
3) Product traceability
4) Lower product liability
5) Transparency for consumer
6) Hard-won brand value

One major potential biological hazard that has been identified in the pet food production process is microbial contamination – specifically from Salmonella . Of the 229 primary contamination sources (industry and regulatory), Salmonella was counted as the most common hazard source (Figure 1).

Specific best practices and guidelines for Salmonella control will be different for each plant, equipment and product. However, there are some specific areas of focus that will be common to all manufacturers. A critical control point (CCP) is implemented in a food safety programme to reduce the specific hazard of Salmonella. Extrusion is the major thermal process used in 95% of all pet food production and extrusion temperature is often chosen as a CCP. There are many studies on the use of extrusion cooking to reduce microbial counts, but few publications regarding pet food processing.

In reviewing practical Salmonella control measures in animal feeds, Jones identified three Salmonella control principles:

1) Prevent contamination from entering the facility
2) Reduce microbial multiplication in the plant
3) Kill bacterial populations

Hurdle technology is another practice to reduce and control Salmonella hazards. Although the normal levels of Salmonella contamination has been associated with elevated levels of indicator organism like Enterbacteriaceae. Fats tend to protect Salmonella from environmental and physiological stresses. Higher moisture content in the environment stimulates population growth. Temperature, time, moisture, and shear are the major processing functions associated with lethality although pressure has to be also considered. 
Many manufacturers extend preconditioning times in an effort to overcome poor mixing in their preconditioning operation and to enhance destruction. Organic acids are occasionally used in recipes and sanitation steps but these are costly, corrosive, and can have adverse effects on production workers, palatability, and vitamin stability.


In order to prove the effectiveness of the selected control measure, a validation step is required by HACCP programmes. Once the validation step has been defined, the extrusion temperature must be monitored to verify that they are actually achieved in production.

There are various approaches to validate the control of the extrusion temperature.

1) Reference to literature, validation studies, and studies from industry or equipment manufacturers.
2) Scientifically valid experimental data that demonstrates adequacy of the control measure through appropriate log reduction of a specific pathogen by a specific process
3) Collection of data during operational plant conditions which may include the use of a suitable surrogate to determine the effectiveness of a CCP.
4) Mathematical and predictive modelling

Recent validation studies specific to pet food

Wenger began his research in 1980 to determine the effectiveness of extrusion as a thermal process to pasteurise ground corn. The results indicate that typical extrusion parameters were effective in reducing and controlling certain microbial populations (Figure 2).

Subsequent studies focused on the impact of a steam preconditioning step as a process control measure. Steam preconditioning is an integral part of the extruded pet food process and continuously blends steam and water with raw, dry pet food recipes prior to extrusion. Coupled with extrusion cooking, preconditioning can provide additional protection as “hurdle technology” in a multiple hazard reduction step.

In 2011, microbial challenge studies using extrusion were conducted at the Bio-Safety Level II Laboratory in the University of Nebraska. Figure 3 summarises the survival of both a Salmonella cocktail and Enterococcus faecium in pet food extrusion at 27.5% moisture. The study indicates that Enterococcus survives at slightly higher extrusion temperatures when compared to Salmonella This characteristic of being slightly more heat resistant makes Enterococcus a good choice as a surrogate for extrusion lethality studies.

Many other factors impact the heat resistance of Salmonella in pet food which are not covered in experimental variables, including the pH, presence of competing organisms, certain food additives, proximate analysis, composition, processing history (including non-lethal heat shock), moisture/water activity and other attachment factors.

Pilot plant studies are desirable in:

1) Determining expected decontamination with different substrates;
2) Resistance of different microbial species to destruction under the same extrusion conditions; and
3) Variations in potential for decontamination among various extruders.

Necessary revalidation of conditions include presence of new pathogens, extreme contamination levels, severe recipe changes, process parameters outside of the critical control limits, and changes in storage or packaging. The lingering problem of how to treat retention time in the extrusion thermal processing continues. Evaluating extrusion as a thermal process with sufficient mixing and temperature in order to achieve a D-value of one second may be an interesting consideration.

Accurate measurement of extrusion temperature

When extrusion temperature is chosen as a process CCP for the control of Salmonella hazards, it is important to accurately measure and control product temperature.

A series of tests was conducted at Wenger to determine the impact of temperature sensor location and mounting techniques on the accurate measurement of product temperature. Actual product temperature was less influenced by environmental and other process factors when this measurement was taken in the die cavity after the screw element and before the final die assembly. Temperature along the extruder barrel was measured at the highest level in the extrusion process. A cross section of the mass of material in the die cavity can display a flow gradient with higher product velocities in the centre of the flow and lower velocities along the die cavity wall.

Occasionally the product flow at the wall of the die cavity can be so low that it may appear to be totally stagnant. It is important to extend the temperature sensor at least 20 mm into the product flow from the side wall of the die cavity to avoid false product temperature readings in the stagnant or low velocity zones.

Extended tip temperature sensors are subject to abrasive wear from product passing through the die cavity and are often protected by metal sheaths. It is advisable to install two temperature sensors in this location, at 180 degrees from each other.

Product temperatures can be displayed where they are readily available for production personnel.

The process control systems can be configured to alarm when process temperatures drop below the critical limits. Advanced control systems not only monitor and record the extrusion temperature, but can also automatically divert product from the process flow when the temperature is below the critical limit.

The farming & feeding of Tiapia – the importance of floating fish food and the use of full fat soya

Tilapia farmingTilapia is a species of fresh water fish, which is indigenous to Southern Africa and which produces a high quality white flesh comparable to that of hake.

In South Africa, Hake has traditionally been the white fish of choice and fishing quotas for 2007 were 120 000 tons p.a., down from 175 000 in 2002. South Africa, who is the only fishery in the world to be certified by the European Ecological Label, now finds itself in a position where hake quotas will have to be slashed further, in order to recover hake stocks, or face losing its EE certification.

Tilapia is also known as Bream, Chambo or a variety of Kurper and is the traditional protein source in a number of sub Saharan countries such as Malawi and Zambia, where it is harvested from the local lakes.

As with the international ocean fish stocks, harvesting has put this resource under severe pressure, where harvests from Lake Malawi have decreased from 8 000 tons p.a. in 1986, to under 500 tons p.a. at the turn of the century. Currently, whole slaughtered fish are sold at ZAR80.00 / kg in the markets on Lake Malawi.

The over harvesting and decreased supply has moved the fish from a subsistence level protein, to that of a semi luxury protein in these regions.

Due to it’s ideal qualities for aquaculture, in 2003 Tilapia was ranked as the 6th largest edible seafood product imported, by volume, into the USA.

Tilapia is increasingly referred to as the “Aquatic Chicken” of the 21st century and provides an affordable alternative food source for internationally depleted hake & cod stocks.

With the growing populations across Africa and the growing food crisis that we face as we head into the future, it is an essential to focus on sustaining the fish stocks by focusing on aquaculture and farming.

An instrumental part of farming Tilapia and other species is determining the correct feed pellet. Not only is the nutritional blend of ingredients essential but also the very nature of the pellet being floating or sinking. What determines this fact will be the determined by the feeding habits of the fish in question. Tilapia and trout are surface feeders and for that reason floating fish food is more suitable. Determining the size of the pellet will be determined by the size of the fish in the breeding pond from fingerling to adult.

Soya is an important ingredient in the fish food. Soybeans are one of the world’s best non-fish sources of essential omega-3 fatty acids, healthy proteins, and unsaturated fats. High-quality soy protein is fed to farmed fish and shellfish, to support their growth and healthy development.

Soybean meal, soy protein concentrates, soybean oil, and other vegetable proteins and oils, can replace from one-third to one-half of the fishmeal in feeds for many farmed species, reducing the need for wild-caught fish for fishmeal.

Soybean meal costs significantly less than most animal meals, including fish meal. Reducing feed cost is critical to improving efficiency and maintaining sustainability in aquaculture operations. Because the nutrient requirements of farmed fish and shellfish are so complex, each feed ratio is formulated based on the individual species’ needs. Most farm-raised fish and shellfish can easily digest soymeal, which helps the fish more efficiently transform ingested protein into body weight.

The extrusion process to manufacture floating fish food involves using a hammer mill to process the raw material of soya or bone meal etc. An extruder is then used to produce the pellets. A more detailed breakdown of the process is as follows:

The individual ingredients are fed into a ribbon blender via dosing augers for the vitamin premixes and ingredients to be added. The product blended for approx. 3 minutes for maximum blend.

It is taken via the variable speed drive auger into the hammer mill (available in 7.5kw, 22 kw, 30kw, 37kw, 55kw, 75kw) with the suitable screen size (available in 0.75mm, 0.9mm, 1.2mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.2mm, 5mm, 8mm & 10mm. Our finest screen 0.75mm is able to produce a product of under 200 micron). It is milled to a spec size then blown via the 7.5kw external drive material blower into a cyclone with rotary valve which feeds into an open trough auger on top of shortened volumetric feeders.

The product is then fed into a pre-conditioner which then feeds the extruder (55kw or 75kw). The product is extruded at 115 degrees Celsius on the gauge then cut with a direct mount VSD cutter unit into the relevant size required for the finished fish food product. It is then transported with an open trough conveyor with blower and canopy into a bucket elevator which feeds a dryer via a rotary valve and then dried. It is then fed onto a conveyor via the rotary valve, this fish food can now be bagged.

The Basic Full Fat Soya Extrusion Process

Every manufacturer of extruders and feed plants have their own method to the final Full Fat Soya product, this is a basic overview of our production process.

ExtrudersThe product is fed from the Silo into the Soya Bean Cleaner and is then fed to the Hammer Mill(available in  7.5kw, 22 KW,30kw,37kw,55kw,75kw) with the suitable screen size(available in 0.75mm, 0.9mm, 1.2mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.2mm, 5mm, 8mm & 10mm). Our finest screen 0.75mm is able to produce a product of under 200 micron.).
From the Hammer Mill it is blown using the 7.5kw External Drive Blower to the Cyclone.  The product is then rotary fed into the Open Trough Auger ontop of Volumetric Feeders which are feeding the extruders via a Variable Speed Drive.
The product is then extruded at 160 degrees and taken via the Open Trough augers into an Incline auger with canopy and blower which blows off the initial steam generated during the extrusion process. The product is then fed into cooling Bins via an open trough auger with gate slides. The finished product can then be bagged-off after cooling from the Bagging-off unit or can feed directly into a bucket elevator into silos for storage.

Properties of the Extruded Full-Fat Soya Bean

High nutrition value of full-fat extruded soy-bean is composed of the following factors determined by processes passing during extrusion:

– Break of fat cells walls that increase availability of digestive enzymes to oil;

– High digestibility of oil;

– High content of non-saturated fat acids.

Fat digestibility during extrusion reaches 80 % that is almost for two times higher than fat digestibility of soy-bean oil cakes (45 %).

Nutrition value of full-fat extruded soy-bean is close to maximally possible value.

Content of raw protein in full-fat extruded soy-bean is the same as in raw soy beans – 38 %. Extrusion increases digestibility of proteins, makes amino acids more available due to damage of secondary connections in protein molecules. Due to relatively law temperatures and short time of thermal treatment the amino acids are not damaged during this treatment.

High nutrition value and great amount of protein in extruded full-fat soy-bean make it a very important component for inclusion into rations of animals and birds.

Amount of protein which does not decompose in rumen in increased in the process of extrusion which is very important for ruminant animals. Full-fat soy-bean is an excellent source of essential amino acids, excluding methionine.

Full-fat extruded soy-bean processed on extruders:

– Is a high-caloric fodder with high content of protein that is universal for all types of animals and birds;

– Protein digestibility is the same as for soy-bean oil cake – over 90%;

– Is characterized by high digestibility of oil, in particular of fat acids required for reduction of thermal stress;

– Contains great amount of tocopherol that provides oil stability during storage. Lipoxidase and lipase are damaged;

– Is characterized by high content of main fat acids – linolic and linolenoic acids – 9.0 and 2.0 respectively;

– Has a high content of lecithin (important for fat metabolism) – 0,7%;

– Has great taste properties.

This provides its main technological properties, in particular:

– Resistivity to long-term storage (up to 6 months);

– Easiness of oil adding to ration. There is no need in special tanks for oil storage and dosing devices for oil adding to combined fodders;

– Great looseness;

– Great ability to granulating (comparing with other components containing oil additives);

– Minimal losses of nutritive components in the process of processing and lack of dust in final fodder product.


Advantages of Full-Fat Extruded Soy-Bean

High nutrition value and great amount of protein in extruded full-fat soy-bean make it a very important component for inclusion into rations of animals and birds.

Use of full-fat extruded soy-bean



Full-fat soy-bean has a great impact on problem of birds’ feeding. High concentration of energy, high level of fat main acids, and low thermal growth required for management of thermal load are the main advantages of soy-bean. High content of linoleic acid is especially favourable for increase of eggs size. Amount of full-fat soy-bean introduced into boilers’ ration is determined by quality of carcasses and marketing purposes.

Economically rational limits of addition of full-fat extruded soy-bean are 10 – 25 %; however, this amount may be increased up to 60 % for broilers.



Full-fat soy-bean is especially recommended for sows at the last stage of pregnancy and for rations during lactation in order to increase health of young animals. This fodder is especially recommended for growing pigs.

Level of full-fat soy-bean during fattening depends on type of fodder. In Europe amount of full-fat soy-bean is usually reduced to maximum 5 % three weeks before butchering of pigs. Otherwise level of soy-bean is determined by economic considerations and as a rule is up to 30 % excluding initial stage of young animals fattening when the level is 5 – 10 % because of high sensitivity of the young animals to inhibitor of trypsin.

In cases when low level of trypsin inhibitor is required it is necessary to use a premixing mixer patented by the company.

Ruminant animals 


(Any of various hoofed, even-toed, usually horned mammals of the suborder Ruminantia, such as cattle, sheep, goats, deer, and giraffes, characteristically having a stomach divided into four compartments and chewing a cud consisting of regurgitated, partially digested food.)

Use of full-fat soy-bean is especially favourable for rearing stock and high-producing cows at initial stage of lactation because of high concentration of energy and presence of “protected” protein. For ruminant animals it is easier to digest amino acids from extruded soy-bean than amino acids from soy beans. It has been noticed that milk cows better digest soy-bean which may be considered as “a bit over roasted” for mono-gastric animals. Extrusion reduces destruction of protein in rumen that increases income of amino acids to small intestine and increases efficiency of soy-bean use.

Full-fat soy-bean may be included into rations of ruminant animals in amount up to 25 % from concentrated fodders.

Domestic animals

Use of full-fat soy-bean is a rather effective method of protein and energy inclusion into fodders for domestic animals. It may constitute up to 30 % from ration of cats and dogs. Oil present in soy-bean provides good taste properties of the fodder.



It is advised to give full-fat soy-bean to cold-water fishes, such as salmon, because this type of fish is adopted to digest soy-bean rather than fodders with high content of small intestine.

Fodders with up to 80 % content of full-fat soy-bean are successively used in the USA. Addition of up to 30 % of full-fat soy-bean to ration of carps also provides good results.


Feeding rabbits with fodders containing up to 25 % of full-fat soy-bean provides rather good results. Oil present in soy-bean is especially well-digested by rabbits. Addition of full-fat soy-bean to dams’ ration during lactation promotes increase of healthy of young animals.

Rabbits are more sensitive to trypsin inhibitor than other animals; this is why it is necessary to be careful during manufacturing of full-fat soy beans for rabbits.