2 PLANT LAYOUT AND CONSTRUCTION DETAILS for Poultry processing ~ University Notes

The poultry industry is very highly integrated in many countries. The date on which the next batch of day-old chicks are required is conveyed to the hatchery. Broiler production has almost standardised on the number of birds/broiler house so the number of day olds for the order is known. Feed manufacturers provide exactly the right amount of the right type of feed for the venture on time. The growth time for the chicks is known so the date of slaughter is contracted automatically. The clear out/clean up time for the broiler house is programmed for the next batch of day-olds to be delivered and in production with no idle time. At the poultry packing house, standard sized birds are delivered according to a contract date and time. They are suspended almost immediately on arrival and slaughtered and processed without delay. Processing speeds are variable but 2500 to 4000 birds/hour are not out of the ordinary. There is evisceration machinery which works at over 6000 birds/hour, and slaughter lines which work at 12 000/hour.

Considering the scale mentioned above, the throughput which forms the basis of this document takes on a new significance. Manufacturers of equipment for poultry processing on a very small scale are few and far between since poultry producers are very much aware of the economies of scale (and are involved in a fiercely competitive industry) and the manufacturers have more interest in the very large scale of opertions.

Development of the Models

Three scales of operation have been chosen to described the construction and operation of small scale poultry processing plants. The first, 50 birds/day, is intended to be an improvement on backyard slaughter. It presents a plan to improve hygiene and product quality on existing systems of small scale production. It can be equipped to process up to 100 birds/hour. The second, 200 birds/day, assumes that the system of operation of the first has led to an increase in demand for the product and there is a need for expansion of operations. It also presents an opportunity to describe other types of equipment and operational systems which can be scaled up to 500 birds/hour. Model 3 is the smallest practical on-line system and offers an alternative to the “manual” production methods described in the first two models. The three models are based on buildings which exist today in developing countries. They show full operational facilities. Other plans, found in Annex 8, show standard layouts of the slaughter facilities only but serve to demonstrate the wide range of facilities which may be required to fit most circumstances overseas where small scale poultry processing factories are required.

Model 1 Very Small Scale Abattoir - 50 birds/day

Economic viability at a production level of 50 birds/day is unlikely to be achieved and therefore social, environmental and public health considerations should be studied (and possibly quantified) at the feasibility stage if the project is to proceed. At this scale there is plenty of scope to increase throughput with a little thought, possibly up to 100/hour. It is difficult to design a smaller plant. A plan of the processing plant is given in Drawing 1. The equipment used, its specification and the staffing requirements are given in Annex 3.

It is the intention that all poultry produced within the plant will be slaughtered, sold and eaten the same day. It is assumed that the area has no history of processed poultry, so the plant is designed to produce New York Dressed birds using a dry plucker. Expensive ice production or refrigeration capacity are neither required nor installed. Dry plucking has several advantages over wet methods. The birds may by plucked “hot” or cold and the microbiological problems associated with scalding and increased surface moisture are not encountered. In New York Dressed birds, contamination and spoilage by visceral microflora is greatly reduced and the shelf life of the carcase is greater than it would be had it been eviscerated and not refrigerated. Dry plucked birds can be kept at tropical ambient temperatures for a few hours only but a couple of hours longer than eviscerated carcases.

As the viscera are left intact, waste materials comprise feathers and waste water only.

The plant is designed as part of a progressive package to be adapted as the market expands.

Model 2 Very Small Scale Abattoir/Processing Room - 200 birds/day

In this model, it is assumed that the locality has a marketing history of processed poultry and is now ready for eviscerated carcases. Reference to Drawing Nos 1 & 2 shows Model 2 to be an expansion of Model 1. Economic viability is not assured.

As the throughput and type of operation has expanded the machinery is changed to include a soft scald system with a bowl plucker, although dry plucking could have continued. Evisceration is carried out and the carcases cooled in either a tank of water cooled by a refrigerated unit attached to the tank or a static tank containing slush ice.

The model is drawn up to show how whole poultry carcases may be packed into bags and chilled. At a later stage of development, chicken portions may be prepared and all the products frozen prior to dispatch.

Details of the abattoir are given in Drawing 2. The equipment required, their specifications and the staffing levels needed to operate it are given in Annex 4. The plan is for the birds to be brought from one large and several small producers and each producer choses to sell his own poultry. In this case, there is a need to label each bird individually and to charge each producer a slaughter fee. This is a difficult operation and needs a larger office and more administration staff than the system where the abattoir management buys the birds from the producer, or the birds belong to a few producers in large numbers.

In this model, the feathers, heads, feet and viscera are to be removed. These materials make up about 25% of the weight of the bird as solid waste which needs disposal. In the drawing, the materials are taken away in a skip for further processing.

Model 3 Small Scale Abattoir - 350 birds/hour

The third example of small scale poultry abattoir chosen for this document will slaughter 350 birds each hour. This scale may approach economic viability in some areas of the world but if not, environmental, social and public health considerations should again be assessed at the feasibility stage.

Slaughter throughputs of between 350 and 500 birds/hour can be processed on simple “static” lines as described for models 1 & 2. Drawings of the equipment and layout required have been included in Annex 6. At about 350 birds/hour, the overhead conveyor system may be appropriate as it allows for greater expansion of the throughput should this be desired at a later stage. Details of the design of the abattoir are given in Drawing 3. Model 3 has been drawn up to show a system of slaughter using an overhead conveyor. The equipment required, their specifications and the staffing levels needed to operate it are given in Annex 5.

The processing plant will slaughter poultry, chill carcases prior to cutting them into portions for freezing. Daily dispatch is planned, as installed freezer capacity is sufficient for only 1 1/2 days production. There is some scope for the preparation of chilled poultry. The birds will be bought by the factory and sold either to wholesalers or buyers of at least 20% of the days production. This reduces the administrative load to manageable levels.

Concerning operation, two types of plucker are proposed, either a bowl or a drum/flail system following soft scalding at 52°C. Evisceration is carried out on an overhead rail system. Since the weight of the by-products will amount to about 750kg/day, feathers, heads, feet and viscera pass to a truck for disposal rather than undergo further processing. However, some suggestions are made later about the possibilities for offal use.

Three carcase chilling systems are proposed. The first is to chill in cooled (refrigerated) water, the second in slush ice followed by drainage on a rack. The third system involves cooling the birds on a rack in an air chiller. The systems are fundamentally different and will require economic analysis before the best system can be advised. Factors to be considered include the capital and recurrent costs of the equipment, its maintenance and spares, the regularity of use, the size of the load regularly slaughtered, microbiological status of the carcase and the weight changes which take place during the two different methods of processing.

Notes on the Drawings

There are some points to note about all sets of drawings. The number of doors to the outside have been reduced to the minimum in the interests of security. In Model 2, a door could be constructed to the outside in the evisceration room in those regions where security is not of great concern.

The dirty and clean operations are separated. “Clean” and “Dirty” workers are separated and there are “windows” through which product passes but personnel cannot. The staff facilities are separated by a corridor and processing rooms do not open directly to the outside. Staff facilities share plumbing runs with others, the laundry in one case and the crate wash in the other. The dry stores are accessible both to deliveries and for the packing room. The machine room is separated from product rooms. Maintenance and service engineers do not need to enter clean production rooms unnecessarily.

The product flows smoothly through the rooms which are separated into reception; slaughter, scalding and defeathering; evisceration, washing and giblet processing; chilling; cutting and packing; chilling and freezing; dispatch.

The equipment, given in the lists in Annexes 3, 4 and 5, is mainly from a specialist equipment supplier but some items are of local fabrication. The general manufacturing principles to follow are given earlier.

Note that the drains flow from clean areas to dirty. Note also the position of service points, particularly wash hand basins, water, steam, electricity, lighting, fans for ventilation and ice.