When considering the setting up of a fruit and vegetable processing plant, whether it be a cottage industry or a small industrial scale system, the first point to bear in mind is the infrastructure required to properly lodge all of the necessary equipment.
Some time must thus be devoted to coordinate two aspects that are vital to the development of a project of this nature, namely costs and the quality of the infrastructure needed to achieve the established goals.
It must always be borne in mind that since the food to be processed is intended for human consumption, the infrastructure must meet several requirements. The basic general aspects of such requirements will be analyzed in this chapter.
The infrastructure comprises different aspects of a project's implementation. Issues like physical layout, basic services or installations and equipment must thus be taken into account.
The physical layout of a plan of this nature may be very simple, as it refers to a basic production system, involving small volumes and simple products, from a technological point of view.
Nevertheless, in the case of a cottage industry and a small industrial scale system alike, simplicity must never neglect the basic principles governing industrial health and hygiene, which must characterize a food production system.
Several different processes take place on the site where the production activity is performed, from the reception and conservation of raw materials, to the storage of finished products.
One aspect that must be borne in mind relates to construction details, which determine a plant's capacity to meet two objectives: to adjust to the production of foods and to ensure a sufficiently long shelf life. However, when considering home or small-scale industrial processing facilities, the cost of construction is an important factor which must be taken into account.
The building materials must be as light as possible, easy to readapt and install, considering that often the system users develop the plan themselves, by means of self-construction methods.
The buildings materials must be easy to readapt because these home-made systems are rather dynamic, that is, they require frequent changes or must adjust to different processes, so that the space that they occupy may be exploited all year round. On the other hand, these systems must be considered "expandable" to accommodate possible evolutions in time.
In addition to the previously mentioned characteristics, the materials must be easy to wash and disinfect, especially those in the clean areas of the processing rooms. Complex type of construction, resulting in the creation of places that are not easily accessible for cleaning must be avoided, for they may turn into bird nests, and contamination foci for rodents, insects, and of course, micro-organisms.
Requirements pertaining to the materials and construction characteristics of the sites do not vary greatly for home processing or small-scale industrial plants. The basic difference lies in the equipment and the way it is set up in the processing lines. The home-processing system is temporary and versatile, and there are no special areas devoted to a single process. In general, all of the premises serve several purposes, according to the type of process and raw material being used.
The small-scale industrial system, on the other hand, is more complex in its organization, and therefore specific activities are carried out in determined areas. Nevertheless, the general requirements for both systems are similar, the difference being in the way such requirements are met.
Some of the aspects that may be considered important in relation to the architectural and construction elements are listed below:
The ceiling and walls of the processing room must be of washable and easily dried materials; they must be neither absorbent nor porous.
- The lighting should be natural, as far as possible. However, if artificial lights must be used, they should not hinder activities in any way. Artificial lighting must be protected, to prevent fragments of glass from falling into the product as it is being processed, in case of accidents.
- Ideally, the working environment should always be appropriately ventilated, to facilitate the workers' performance. Poor ventilation in highly enclosed and densely populated premises may generate defects. It is also important to provide for the elimination of heavily contaminating odours, even if they are not necessarily toxic.
On the other hand, excess ventilation, especially in places characterized by great aerial contamination external to the processing site, dust and insects essentially, may prove to be counterproductive. Appropriate ventilation must therefore be based on an efficient system controlling the access of foreign material from the external environment.
- The floors must be of a solid material, never earth or plant covering. Like the walls and ceiling of the processing room, the floor must be washable, to ensure compliance with the premises' hygienic and health standards. The floor must also be sloped to allow appropriate drainage, avoiding at all costs the formation of pools in the processing area. At the same time, care must be taken to prevent the floor from being slippery.
These are some examples of the features that must characterize a fruit and vegetable processing site to guarantee a quality product suitable for human consumption.
Three basic services are required for the operation of a system as the one in question: electrical power, drinking water and the disposal of waste waters.
Occasionally, small-scale industrial plants are equipped with a steam production system, which however is more seldom found in home-processing plants.
Even when a home-processing plant can operate without electrical power, it is better for this service to be available, essentially to facilitate the processes by means of small devices that were developed and that improve workers' performance, thus guaranteeing a greater uniformity of products.
Electrical power is also absolutely necessary if one is to rely on an appropriate lighting system, so that work shifts may be prolonged, especially when there is a surplus production of raw materials.
In small-scale industrial production systems, electrical energy is indispensable, due to the greater degree of mechanization of the processes involved. All lights must be installed on the ceiling at a safe distance to prevent them from getting wet and getting in the way of workers in the processing room.
As to water supply, the problem is slightly more critical. Sufficient drinking water must be available to ensure the development of a hygienic process, managed by clean people and with appropriately disinfected equipment. Also, many processes require water, as a result of which water of an appropriate quality must be available.
Since water does not come in abundant quantities, its use must therefore be regulated by strict savings principles, especially in small or home-processing installations that normally are not equipped with sophisticated water harnessing devices. Water must be protected from possible sources of contamination and must be supplied on a continuous basis at all times. The consumption of water will depend upon the process in question and the design of the production systems.
The supply of water must be ensured on a permanent basis, as a result of which the plant will need to be equipped with an elevated storage tank to avoid being dependent on the supply of electricity. A reserve must be created, so that water is available even when there is no electrical power. Tank storage will also allow for treatment through the addition of disinfectants.
In general, it is advised that chlorine be added to the water supplying the entire plant, so as to provide for permanent disinfection. To this end, a dose of 2 ppm of residual free chlorine is suggested. It should also be borne in mind that the tank must be covered and not exposed to sunlight, to prevent the chlorine from decomposing. As a term of reference, 100 ml of a sodium hypochlorite solution for every 2000 liters of water may be used, assuming that the hypochlorite solution contains about 50 mgr of active chlorine per litre of solution. This will prevent the water from having any chlorine-like taste.
A fruit and vegetable processing plant must be set up in such a way as to rely on a number of basic facilities, which are generally similar in home-processing and small-scale industrial systems. Figure 1 shows a small-scale industrial production system for the processing of fruits and vegetables.
Reception of Raw Material
The plant must be equipped with a special area for the reception of raw materials, that is, a site where the raw material received in appropriate conditions may be stored until it is used in the process. This site, which may simply be a shed or a more appropriately designed room, must meet certain special standards in terms of temperature, humidity cleanliness, and exposure to sunlight. It is important to consider that the quality of most raw materials covered in this manual rapidly deteriorates. That is, even though many species do preserve their integrity, their inner quality is subjected to variations if storage conditions are less than adequate.
It is for this reason that the temperature must be as low as possible; it must be cool. The raw material must not be directly exposed to sunlight. Since storage temperature is a very important factor, if a refrigeration system is not available, the material must be collected in the cool hours of the day.
If the storage site is cool, it is important for the humidity to be relatively high to prevent the material from dehydrating and losing its quality. This problem does not apply to areas with a high relative humidity, in which case the only requirement is to find a cool site.
It is important to underscore that the raw material storage area must not be used for the storage of other products that may be contaminating, such as pesticides, paint, or cleaning utensils, all of which must be kept in specially designated areas.
It must never be forgotten that the quality of the product will reflect the quality of the raw material from which it was made; it is therefore important to take this aspect into due account.
This storage site must be provided with basic equipment for the reception of the material. The scale and other instruments for primary quality control must be kept in a safe place, where they will not be damaged. An appropriate place must have an average temperature no higher than 30°C and a humidity no greater than 70%. The tools must be kept in their respective cases at all times, clean and dry.
FIGURE 1. Fruit and vegetable processing plant.
FIGURE 2. Double-bottom kettle
FIGURE 3. Hand press
The processing room is the main facility in a plant of this type. It is here that the different materials used in the processing of the raw material are stored. On such premises, a continuous production line may be set up, or simply an ensemble of small machines allowing the products to be processed by hand and on a discontinuing basis. Ideally, this room should be big enough to lodge all of the necessary equipment on a continuous line, even in barely automated facilities. Even in the case of work benches where the work is performed by hand, the process must be carried out on the basis of a continuous line, to step up efficiency.
The processing room should ideally be divided into areas where different functions are performed. This may be achieved by separating such areas physically. Generally, there is a "dirty" area, that is, an area where the raw material is washed and peeled, and where operations like pitting, coring, and the removal of inedible parts are performed. This "dirty" area must not extend to the section of the plant or of the processing room where the cleanest operations are carried out, like pulp extraction, grinding, cutting and the filling of containers.
One way of achieving this separation is through the use of light partitions, painted wood panels used to simply separate one area from the other. Much care should be taken to avoid contamination by run-off waters. The recontamination of materials that have already been washed and disinfected is a common problem in home or small-scale industrial processing plants.
Ideally, quality control operations should be performed in small quarters, which may also be separated from other areas by wood panels, where the basic tests required to establish the quality of a given raw material or a given process may be performed. This area should preferably be equipped with a small sink, running water and a counter where tests may be carried out.
It should be separated from the other quarters so that basic calculations may be carried out in a quiet environment.
Storeroom for finished products
The storeroom is fundamental in a plant of this type. It is often necessary for the product to remain under observation before being consumed. Sometimes, the products must settle for a while to achieve a certain level of homogeneity, whereas in other cases the material must await labelling. Finally, in addition to being able to rely on a room where the material may be safely stored, it is also necessary to have access to a site where the process may be completed. Such a place must be clean, the temperature and humidity levels must be appropriate (less than 25 C° and 60% of relative humidity), and it must be protected from foreign matter, and naturally, from thieves. It should be easily accessible, so that tests may be performed during product storage, and any problems may be detected on the spot.
Some equipment, due to its nature, cannot be installed in the main facility of a processing plant. The boiler is an example. If the plant is equipped with a small steam generator, it should be located outside the processing room, to avoid contamination problems, and at the same time ensure personnel safety.
A drier is another special system, which should be installed in a rather dry place and not in the processing room, as this is an especially humid area in the plant.
Dehydrated products should normally be very low in moisture, a condition that can only be fulfilled if dehydration is carried out in an especially dry place, even if an artificial drier is employed. Otherwise, the energy consumption cost will be very high, since a great amount of heat will be required to dry the air.
Sanitary facilities are believed to deserve special mention, due to the significant role that they play in preserving health and sanitary standards in a plant of this type.
The conditions in which the sanitary facilities operate, the type of evacuation system serving the plant, the location of the facilities and the sanitation plan are crucial to the quality of the process.
One basic condition is for the facilities to be erected in a separate location from the area where the raw material is received and processed, to prevent possible flooding. The facilities must be periodically disinfected, and the firm's supervisors must exercise very strict control in this regard.
It should be borne in mind that even though the current cholera outbreak in Latin America is viewed as an isolated case, health care should not be a priority in times like these alone.
Indeed, there is always some micro-organism around that may be detrimental to the health of whoever consumes the product.
Sanitary facilities must never be short of water. Its supply must be guaranteed, since the cleanliness of the toilets will determine the cleanliness of the workers, and the products' sanitary qualities will ultimately depend on the cleanliness of the workers.
Figures 2-4 and pictures 1-20 illustrate different implements and machines comprising the basic equipment required for the home processing of fruit and vegetables. Figure 2 shows a steam-powered heating system, figure 3 shows a press for the extraction of juice, and figure 4 shows a pulp removing machine.
The most common processes that apply to fruit are drying, preservation, pulp concentration, the manufacturing of juice, nectars and sweets, and concentrated pulp processing.
Home Processing Equipment
Pictures 1 to 4 illustrate milling systems. In the first case, a pulp extractor used for fruit as well as tomatoes and vegetables is shown. It is provided with a sieve to separate the seeds and skin from the juice, which is the basic raw material to be used in the process.
Picture 4 shows a common hand powder separating sieve.
Picture 5 shows a multiple use kit containing a series of materials for fruit processing. This kit is used for training courses, but it contains all of the elements which, on a larger scale may constitute the basis for the home processing of various fruits and vegetables.
Picture 6 shows a cooking system easily installed in sites characterized by more precarious conditions. Some of these systems may be installed indoors using the chimney system shown in picture 7.
Picture 1. Electrically powered pulp extractor. (G. Paltrinieri)
Picture 2. Manual pulp extractor. (TCP/BKF/6658 Project)
Picture 3. Hand mill. (G. Paltrinieri)
Picture 4. Commonhand sieve. (G. Paltrinieri)
Picture 5. Kit containing the equipment and demonstration materials. (G. Paltrinieri)
Picture 6. Easy-to-install sterilization system. (G. Paltrinieri)
Picture 7. Easy-to-install cooking system. (TCP/BKF/6658 Project)
Picture 8. Movable solar drier. (TCP/BKF/6658 Project)
Pictures 8-12 show different easy-to-build drying systems, some cheaper than others, but low-cost in general and fit for the process.
Picture 13 shows a sealer for flexible plastic containers, which is of great use for the packaging of jams, sweets and dried products.
Pictures 14-16 show three bottle capping machines which use crown caps and are frequently employed in the manufacturing of drinks and sauces.
Pictures 17 and 18 show other items comprising the multi-use kit, a scale and a citrus fruit extractor.
Finally, pictures 19 and 20 show a refractometer, an absolutely indispensable instrument in fruit and vegetable processing, used to measure the concentration of sugar in products preserved according to this method.
In summary, the materials and equipment considered to be the basis of a fruit and vegetable home processing plant will be illustrated in the following pages, along with the minimum requirements for the processing areas, the materials and equipment required to perform demonstrations and commercial processing of fruit and vegetables. All of these aspects are fundamental to the setting up of small rural agroindustrial enterprises.
Specifications for the building or adaptation of industrial premises
- A processing area (5(10) x 10 m approx.) possibly equipped with a ceiling fan, a mosquito-net and a room in which to store packaging material, additives and finished products (4 x 4 m). Ample natural and artificial lighting.
- Sanitary facilities outside the processing area.
- Electrical power supply, and to the extent possible, sockets on each wall of the processing area, high up above the ground and away from the humid floor.
- Double dishwasher, preferably enamelled or of stainless steel, with running drinking water.
- Two double gas stoves, with their respective cylinders and regulators. As an alternative, electrical, paraffin or firewood-generated heat may be used.
- Drinking water (in the processing area and surroundings).
- Two enamelled or painted wood tables (180 x 120 x 80 cm approximately), with a galvanized steel or ideally a stainless steel covering.
FIGURE 4. Components and diagram of a pulp extractor.
- Bottles with crown cork. As an alternative, use between 500 and 1,000 disposable or returnable beer bottles (of approximately 200-280 ml).
- Between 2,000 and 5,000 metal crown cork.
- 500 glass jars (of 450 gr approximately) with screw-on or twist-off lids.
- 200 glass jars (of 900 gr approximately) with screw-on or twist-off lids.
- Screw-on or twist-off lids for jars of different sizes.
- Adhesive labels for bottles and jars.
- Citric acid, 500 gr, or lemon juice, 3 litres.
- Pectin powder for foods, 2 kg.
- Refined sugar, the amount of which will depend on the volume of the product to be obtained.
- 10 empty sacks of flour (1m x 0.5 m approximately).
- 1 kg of sodium benzoate for foods, optional.
- 1 kg of potassium sorbate for foods, optional.
- 1 kg of sodium metabisulfate, optional.
- Caustic soda.
- Scale (from 50 to 100 kg).
- Scale (from 3 to 5 kg).
- Scale (from 100 to 500 gr).
- Hand refractometer (0 - 90° Brix)
- Refractometer (0 - 30° Brix)
- Stainless steel thermometer (0 - 150°C)
- 2 cast aluminium pots with lid (with a capacity of approximately 50 litres).
- 2 cast aluminium pots with lid (with a capacity of approximately 10 litres).
- 2 cast aluminium pots with lid (with a capacity of approximately 5 litres).
- 10 wooden chopping boards (40 x 30 cm).
- 5 stainless steel knives with a thick blade (15-20 cm x 2 cm).
- 5 stainless steel knives with a thick blade (10 cm x 1 cm).
- 5 colanders (25-20 cm diameter) with aluminium mesh.
- 5 plastic trays (40 x 60 x 5 cm).
- 10 plastic buckets (20 litres).
- 10 plastic buckets (10 litres).
- 2 plastic or aluminium funnels (20 cm diameter).
- 2 plastic or aluminium funnels (15 cm diameter).
- 3 stainless steel spoons of different sizes.
- 3 large plastic spoons.
- 3 medium wooden spoons.
- 3 large wooden spoons.
- 2 manual pulp extractors/separators.
- 2 manual cappers for crown cork.
- 5 perforated plastic cases for fruit for 18-20 kg.
When analyzing the equipment required by a small-scale industrial plant, it may be observed that there are no great differences in terms of basic principles.
The difference essentially lies in the size and application of electrical and mechanized equipment of a greater unit capacity, probably characterized by a greater resistance and durability, but based on the same technological principles.
In the specific case of a semi-industrial plant, the pots will be replaced by steam kettles, heating will be provided by a steam-boiler, and a small press as well as an autoclave will be available. A list of additional equipment that must be installed in a small-scale industrial plant is provided below.
- A small boiler producing 250 kilos of steam per hour.
- A vertical autoclave with a capacity for about 200-500 g jars.
- A pulper, which operates manually or electrically.
- A hand-operated hydraulic press.
- A pressure bottles closer.
- Two double-wall kettles.
Figure 5 illustrates the procedures involved in the preservation and processing of concentrates, in which the handling takes place on a larger scale as compared to home processing. It may also be observed that with the exception of the vacuum evaporator (9), the rest of the equipment is rather similar to that analyzed in the previous section, with a significant difference in size but governed by the same principles.
Since it is larger, automated to some extent and characterized by a greater use of electricity, a small-scale system requires installations in better conditions than a home processing system, although such requirements are significant in terms of space only.
FIGURE 5. Jam making plant
Picture 9. Stationary drier (TCP/BKF/6658 Project)
Picture 10. Sun drying of-peeled peaches. (G. Paltrinieri)
Picture 11. Solidly-built stationary solar drier made of concrete, metal and glass. (G. Paltrinieri)
Picture 12. Electric fruit dehydrator. (TCP/JAM/0154 Project)
Picture 13. Electrical sealer for flexible plastic bags. (G. Paltrinieri)
Picture 14. Bottle capper with a crown cork. (TCP/BKF/6658 Project)
Picture 15. Crown corks. (TCP/SEN/8954 Project)
Picture 16. The crown cork being placed under the capper's magnet (TCP/BKF/6658 Project)
Picture 17. Weighing pectin on a scale. (G. Paltrinieri)
Picture 18. Lemon squeezer. (G. Paltrinieri)
Picture 19. Refractometer to measure the Brix°. (G. Paltrinieri
Picture 20. Refractometer to measure the Brix°. (G. Paltrinieri)