Chilled and frozen foods

Hygienic aspects of designing enterprises for the production of chilled foods

Дж. Хола и P. X. Торп, Campden and Chorleywood Food Research Association


The main task of producers of chilled products is the production of a healthy one, that is, having all the signs of freshness and quality, characteristic of chilled products, and a safe product (without pathogenic microorganisms, chemical contaminants and impurities). In the refrigerated sector, this is especially important because, due to its nature and production methods, many of them are high-risk products.

The scheme shown in Fig. 13.1, typical for all food production and shows that the production of safe, healthy products is based on a thorough risk analysis. Currently it is a requirement of the law. It follows from the figure that, in the presence of certain raw materials, the work of the enterprise to ensure the production of safe healthy products is determined by four blocks: the hygienic design that determines the design of the production room and the choice of equipment; safe, reliable technological processes developed in the development of technology; hygienic production methods and process control.

Hazard analysis involves identifying hazards that may affect the quality or safety of a food product, and managing them at all stages of the process so as to minimize product contamination. In the food industry, this is commonly referred to as Hazard Analysis at Critical Control Points (HACCP).Driving enable production of safe and healthy chilled products

Fig. 13.1. Driving enable production of safe and healthy chilled products

These risks typically include:

  •  biological - for example, bacteria, yeast, mold;
  •  chemical - for example, detergents and lubricants;
  •  physical - for example, glass, insects, rodents, metal, dust.

In food production, risk analysis should be carried out as early as possible, if possible even before the design and construction of production premises, since the design of an industrial building plays a major role in eliminating hazards or reducing risks.

Of the four blocks shown in Fig. 13.1, in this chapter only one is considered - the hygienic aspects of design. For food production, the hygienic aspects of design begin with the selection of the construction site and building structure. At the same time, such aspects as building design, selection of methods and materials for surface finishing, separation of work areas to prevent risks, directing raw materials and finished products, moving and monitoring personnel, designing and installing process equipment, designing and installing air supply systems are considered. , water, steam, electricity, etc.

There are several EU Directives regulating the production of certain types of products (from meat, fish and eggs) with requirements for premises. 14 June 1993, the Food Hygiene Directive (Council Directive 93 / 43 / EEC) was adopted, which applies to the production of all food products, and it is more specific than all previous documents. The first of its ten chapters deals with the general requirements for industrial premises, and the second with the specific requirements for the premises where products are prepared, cleaned or processed; in the 3 chapter, only areas and catering facilities are described (tents and market stalls, for example, are excluded from consideration).

Separation of working areas

The production of chilled food products should be designed as a sequence of barriers that limit the entry of pollutants. The number of barriers created depends on the type of product and is determined on the basis of the analysis according to the HACCP method. From fig. 13.2 shows that in food production there are usually up to three levels of separation.

At the first level, the choice is made of the construction site of the enterprise, the external fence and the zone to the wall of the enterprise. At this level, they provide barriers against environmental exposure (for example, prevailing winds, unauthorized access by unauthorized persons), and also exclude places that can serve as a haven for pests.

At the second level, production fencing and other means (for example, UV-flycatchers) are envisaged, which should separate the enterprise from the external environment. Obviously, an enterprise cannot be completely hermetic, however, its floors should ideally not be at ground level, and the openings / holes should be designed so that when used they are impermeable to pests.A schematic arrangement of the company with an indication of the barriers

Fig. 13.2. Schematic location of the enterprise with indication of barriers against pollution. 1 - perimeter fencing; 2 - walls of main industrial buildings; 3 - walls of high purity zone

At the third level, they ensure the creation of internal barriers used to separate industrial technological processes with different degrees of risk, for example, the processes before and after heat treatment. Such a separation should help control the quality of the atmosphere, check the sanitary and hygienic state of personnel and surfaces (for example, the floor and drainage system), as well as ensure convenient movement of materials and equipment through this barrier.

The territory of the enterprise

Attention paid to the design, construction and maintenance of the area around the enterprise, allows you to install the first, outer of a number of barriers that protect production from pollution. It is recommended to take all reasonable measures to reduce the pressure that can affect each barrier, forming a common protection system. Thus, a well-planned and properly equipped area can contribute to the fight against rodents, insects and birds by reducing the amount of food available to them and places for breeding.

In [14], it is proposed to use two lines of rodent baits located every 15-20 m along the perimeter of the external fence and at the foundations of the enterprise, as well as several mousetraps near the entrances to the building. In [20,30], it is proposed to keep the area adjacent to the buildings free of grass and cover it with a thick layer of gravel or stones, which helps in weed control and when checking traps with bait.

Fight against birds is very important, as their colonies can cause serious problems. The work of [22] emphasizes the importance of the strategy of turning the territory of an enterprise into a place unattractive for birds, due to the deprivation of their food and nesting sites. The authors recommend not to leave waste in open containers and quickly clean up any remnants of raw materials.

In [22] it is indicated that many insects are carried by the wind, and therefore they are inevitably present in the enterprise. The authors note the importance of preventing the unauthorized opening of doors and windows, as well as the installation of protective screens against flying insects, although [19] notes that such screens create maintenance problems. When considering options for lighting warehouses and outdoor security systems that attract night insects, high-pressure sodium lamps are recommended rather than mercury. The entrances, which should be illuminated at night, should be illuminated from a certain distance, with the light directed at the entrance, and not directly from above (this prevents flying insects from being attracted directly to the entrance). Some flying insects need water to maintain their life cycle (for example, mosquitoes). Experience shows that where flying insects are capable of creating problems, all places where water can collect for a long time (old buckets, drum covers, etc.) should be removed and controlled.

Proper arrangement of the territory, as well as a reasonable placement of any preliminary cleaning operations for raw materials (for example, root crops), which are often carried out outside the enterprise, can reduce the amount of dust entering the plant.

In [19] it is recommended to orient the buildings so that the production areas are on the leeward side of the enterprise with respect to the prevailing winds. The location of transport routes around the territory can affect the amount of soil that is transferred to buildings by air. In [22] it is indicated that in some locations of enterprises it may be necessary to limit the routes of heavily polluted vehicles to reduce dustiness.

Company building

The building itself is the second and main barrier, which protects raw materials, technological equipment and finished products from contamination or deterioration. Protection is provided both externally - from environmental influences (rain, wind, surface water, transport, dust, odors, pests, foreigners, etc.), and internal - against microbiological hazards (for example, cross-contamination of raw materials), chemical and physical risks (for example, from exposure to each other of various areas of the enterprise). Ideally, the buildings of an enterprise should be designed and constructed so as to be suitable for the operations carried out in them, without imposing restrictions on the choice of the technological process or the location of the equipment.

Regarding the type of building, single or multi-storey, the advantages and disadvantages of such types of buildings are described in [19]. It is believed that a compromise can be reached when using a single-story building with a variable internal height, which is achieved with the help of intermediate floors constructed with the ability to carry out the flow of materials. For most operations with chilled products, single-storey buildings are more preferable, since they usually make it easier to meet the requirements for designing high-risk areas. It should be noted, however, that in modernized buildings it may not be possible to take advantage of some of the advantages mentioned in [19]. Of particular concern in high-rise buildings are air and fluid leaks from above and below the processing zones of products. The authors undertook research at a number of enterprises where contamination entered high-risk areas due to leakage from above (through floor defects and poorly maintained drains). In addition, in some cases, runoff systems acted as air distribution channels, with air from low-risk areas (top and bottom) entering high-risk areas. This usually occurs when drains are used little and the water gates dry up.

The location of the enterprise is of paramount importance for the economy and safety of the technological process and should be such that the direction of movement of materials during their processing is as straight as possible. Straight movement minimizes the possibility of contamination of the processed or semi-processed product with raw or raw materials and makes movement more efficient. In addition, it is easier to separate the “clean” and “dirty” technological operations and limit the movement of personnel from the “dirty” areas to the “clean” areas. Although ideally the process should go in a straight line, in practice it is quite possible. However, there should be no returns, and where changes in the direction of movement of the product occur, appropriate physical barriers should be provided.

The location of the enterprise should also provide for the provision of space necessary for the execution of the technological process and the associated quality control functions (both at the time of production start-up and in the foreseeable future). There should also be a place to store and move materials and personnel. As noted in [22], around most installations should be provided with a minimum width of 915 mm (3 feet), although for efficient production, cleaning and maintenance the size of the passage must be 1830 mm (6 feet).

In addition to technological zones, it may be necessary to provide places for performing certain operations, including: storage of raw materials, packaging, and water: a storeroom for sanitary facilities; workshop; detergent storage facilities; microbiological and chemical laboratories, as well as quality control laboratories; kitchen for testing products; pilot plant; wardrobes and rest rooms; toilets; dining rooms; medical offices: observation areas (galleries); areas for sorting finished products and their storage, etc.

The following additional design requirements are given in [22]:

  •  air flows and drains should be directed from “clean” to “dirty” zones;
  •  flow of waste materials for outer packaging: should not cross the flow of unpackaged ingredients or finished products or move towards them.

Detailed information on the sanitary and hygienic aspects of designing for the construction of external production walls is quite difficult to find. Most of the data available concerns purely technical requirements, which we will not discuss in this chapter. In [19, 22, 26], various methods of building external walls are considered and advice is given on pest control measures (especially rodents). A typical example of an acceptable exterior wall design is shown in Fig. 13.3. The diagram shows a well-sealed structure that prevents rodents from accessing and is protected from external damage by transport. The first floor of the enterprise is above ground level. The prevention of direct access to the enterprise at the level of the ground floor limits the flow of contaminants (dirt, soil, foreign bodies, etc.) during the movement of vehicles (forklift trucks, transport, raw materials, etc.).

The above sources contain a lot of information about the hygienic requirements for various openings in external walls, in particular, doors and windows. The following aspects are of particular importance:

  •  doors must be made of metal, glass fiber reinforced plastic or plastic; they must be closed automatically and be designed to withstand the specified mode of use; they should be protected from possible damage by transport;
  •  exterior doors should not be opened directly in the production area; when they are not used, they must remain closed; a curtain of plastic strips may be used as an internal door;Exterior wall construction is an example of a well-sealed structure with a raised floor level of a building.

Fig. 13.3. Exterior wall construction is an example of a well-sealed structure with a raised floor level of a building.

 whenever possible, enterprises should be designed without windows in the food production area, and if it is impossible, the windows should be reinforced with polycarbonate or laminated; should also be able to observe for visitors or management. At the enterprise should keep records of glasses with an indication of the types used and their location;

 metal or plastic frames should have internal sills with a slope of 20-40 ° (to prevent their use as temporary storage) and outdoor window sills with a slope of 60 ° so that birds do not sit on them;

 opening windows in the production areas should be equipped with nets.

Production of high-risk areas

Unfortunately, the term “high risk”, which is also used to describe other products (for example, slightly acid canned products), turned out to be associated with a specific area of ​​the enterprise in which chilled products are produced. The terms “high-risk zone” and “low-risk zone” are often used to describe those areas of an enterprise that produce chilled products that use different hygiene requirements.

Such terminology is considered to be misleading, and its use for personnel may mean that in areas where, for example, operations involving the reception of raw materials, storage and initial preparation are acceptable, lower general standards are acceptable. In practice, all operations related to food production should be carried out in accordance with the highest sanitary and hygienic requirements. Unsatisfactory regimes in the so-called “low risk zones” can lead to an increased effect on the barrier system separating the zones. Although this terminology is undesirable, it is likely to continue in the near future. The use of methods closer to pharmaceuticals in food production can lead to the use of appropriate pharmaceutical terminology, for example, the term “clean zones”.

The United Kingdom Chilled Food Association [5] has established basic principles that describe the hygienic status of chilled foods and areas where they should be processed after any heat treatment. Three levels are distinguished: high risk zone (gold reserves) or production zone (PZ), high purity zone (HRA) and clean zone (43). Their definitions are:

  •  PZ: area for processing only those components that have been heat treated at a temperature> 90 ° C for 10 minutes or> 70 ° C for 2 minutes; there is a risk of contamination in this area between the heat treatment and the sealing of the package, which could make the products dangerous;
  •  ZPCH: area for processing components, some of which were heat treated at temperatures> 70 ° C for 2 minutes; there is a risk of contamination in this area between cooking and sealing of the package, which could make the products dangerous.
  •  43: area for processing components, none of which was heat treated at> 70 ° C for 2 minutes; there is a risk of contamination in this area before the packaging is sealed, which can make the products dangerous.

In practice, the definition of HRA is expanded and includes a zone for further processing of components that have undergone a disinfecting treatment (for example, fruits and vegetables after washing in chlorinated water or fish after cold smoking and salting).

Most of the design requirements for PP and HRA are the same, with a focus on preventing infection in the PP and minimizing infection in the HRA [5]. Having determined that a company needs a PP or HRA, and therefore what requirements should be met, manufacturers of chilled products should carefully consider the existing and future product range, the hazards and risks associated with them, as well as possible new developments. If budgets allow, it is always cheaper to build from the beginning of construction in accordance with the highest standard than to try to reconstruct or update something later. The recommendations of this chapter are aimed at meeting the requirements for high-risk operations.

Strategy in relation to Listeria

For refrigerated foods, the most dangerous contamination is microbiological, especially from the pathogen Listeria monocytogenes, which is most often associated with the ability to grow in refrigerated foods.

L. monocytogenes in many refrigerated foods can be associated with the raw materials used, and therefore it can be detected in a low-risk area. After heat treatment of the product or decontamination (for example, washing) it is necessary to take all measures to protect the product from cross-contamination from sources of L. monocytogenes from areas with lower risk. Similarly, contamination by impurities and foreign bodies, which may be associated with the risk of reducing the usefulness of the finished product, can also be found in a low-risk area. The authors have developed a three-stage strategy to reduce the infection of the finished product L. monocytogenes and at the same time - to combat other sources of pollution, namely:

 ensure as much as possible barriers to prevent ingress Listeria in high-risk area;

 prevent the growth and spread of any Listeria penetrating these barriers during production;

 To ensure that all Listeria is removed from the high-risk area prior to resumption of production, after the production of the product, use an appropriate system of sanitary measures.

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