Saturday, August 14, 2010

Hygienic Design of Fish Processing Plants

Hygienic design of fish and food handling areas is concerned primarily with prevention of microbial hazards, but should also include consideration of occupation safety, convenience of handling or even aesthetics. This article will deal mainly with the reasons behind the hygienic design requirements, stressing the particular hazards involved and their control. In terms of microbiology, this includes preventing contamination of the product and limiting multiplication and spread of microorganisms in the environment.

Food including fish has to pass through many operations as they are handled from the very first steps of harvesting or primary production to the final stages of distribution, retailing and handling in food service establishments or in the home. Hygienic aspects of the sign of food operating areas have to be considered in respect of:

a. Production, harvesting and slaughter;
b. Incoming raw materials;
c. Processing;
d. Storage;
e. Distribution, handling and use
- In wholesale markets and retail premises;
- In food service establishments;
- In kitchens.

In each of these categories, great variability exists in the size and the extent of handling (e.g. a small fishing boat compared with a large factory vessel; a rural market in a developing region compared with a supermarket in an industrialized region). Accordingly, the hygienic requirements for the design of a food handling area may vary considerably even when the same foods are handled. All design factors commonly listed in legislation and codes of practice are not equally important in respect of hygiene. The more important factors include facilities for water supply, waste-disposal and cooling and cold storage facilities. Of less importance with respect to microbiological hazards are buildings (including floors, walls and storage rooms), ventilation, factory location, and clothes changing facilities, lighting, and roadways. However, all requirements need be considered in order to meet national and/or international requirements.

Some General Considerations and Definitions
For a better understanding of the problems involved it is necessary to consider briefly a few terms which are often used, particularly in the Codes of Hygienic Practice.

‘Designed in a hygienic way’
In microbiological terms, this means the creation of environmental conditions, which are not conducive to the growth of microorganisms. Thus, no facilities may be deemed ‘hygienic’ that offers an opportunity for the accumulation of organic matter and/or moisture (e.g. edges, nooks, crevices, fissures, breaks, cracks and scratches or absorbent materials which are resistant to cleaning).

‘Easy to clean’
This is closely related to the term ‘hygienic’. It refers to the arrangement of construction elements with an area (e.g. surfaces of the ceilings or walls, arrangement of pipes leading from sinks or tanks to the wall or to the ground). Dirt, soil, and moisture cannot be easily removed from floors unless joints between walls and floors are covered. ‘Easy to clean’ describes any design, which will minimize the efforts required for thorough and effective sanitation operations.

In respect of the handling of fish, it has proved useful to distinguish three categories of surfaces encountered within a processing facility

a. Surfaces of materials that are intended to are exposed to foods (e.g. silos and storage bins). The risk of contamination of foods is high.
b. Surfaces of materials not intended to be exposed to foods, but which may accidentally have such contact (e.g. walls in a processing area). The risk of contamination of foods is low.
c. Surfaces of materials not intended to be exposed to foods (e.g. floors and ceilings in processing areas). These are of concern primarily for aesthetic reasons and for safety of personnel but need to be cleanable and kept clean. The risk of contamination of food is low.

‘Clean and unclean’
These terms cannot be defined precisely because their meanings are relatives and vary with the intended purpose and with the products. In fact, there are several degrees of cleanliness. The requirements for cleanliness for storing raw agricultural products are quite different from those in a filling section of Ultra High Temperature milk in dairy plant.

Location and Surrounding Area
In the design phase of fish harvesting and processing areas, several aspects are of particular concern in respect of hygiene. These may include:
a. Proximity of potential source of contamination;
b. Sufficiency and quality of water supply;
c. Waste water removal;
d. Adequacy of power supply, particularly in emergencies;
e. Availability of transportation.

Climate can have an important bearing on design criteria. For example, average, minimum and maximum annual temperatures and relative humidifies must be taken into account in the design of facilities and may require different approaches in hot humidity climates than in cooler, drier regions.

Potential locations for fish plants should be surveyed to assess possible hygienic hazards, e.g. nearby dumping areas may contribute to atmospheric pollution and harbor vermin. Fish handling establishments should not be located close to bone yards, stables or other places where live animals are held or to establishments handling skins and hides such as tanneries, waste disposal sites and other enterprises which deal with highly contaminated material.

To prevent accumulation of water and the generation of dust, roadways and yards serving the establishment should have a hard, and where practicable, paved surface, and adequate drainage.

Hygiene and the Design of Facilities
The micro flora of processing plants is composed of microorganisms that gain entry from the air and water and, more importantly, those brought in by animals, raw materials, dust, dirt, and people. Equipment may also serve as vehicles of contamination.

The following general principles can be summarized for the hygienic design of fish handling areas:

a. Arrangement of Rooms, Areas and Processes within Establishments
- The plant and surrounding area should be such as can be kept reasonably free from objectionable odors, smoke, dust, or other contamination. The building should be sufficient in size without crowding of equipment or personnel, well constructed and kept in good repair. They should be of such design and construction to protect against the entrance and harboring of insects, birds, or other vermin, and to permit ready and adequate cleaning.

- Fish processing plants should be designed and equipped so that all handling and processing operations can be carried out efficiently, and all materials and products can pass from one stage of processing to the next in an orderly manner and with minimum delay.

- Areas where fish are received or stored should be so separated from areas in which final product preparation or packaging is conducted as to prevent contamination of the finished product.

- Separate and adequate storage should be provided for wood, saw dust or similar materials used in smoking of fish.

- Separate and adequate facilities should be provided for drying fish.

- Salt and other ingredients used in the curing or processing of fish or fish products should be stored where appropriate in a dry state and in a manner to prevent their contamination.

- Storage facilities should be available for the proper dry storage of packaging materials.

- If poisonous or harmful materials, including cleaning compounds, disinfectants and pesticides are stored, they should be kept in a separate room designed or marked specifically for this purpose.

b. Structural Components of Establishments
- Floors should be hard surfaced, non-absorbent and adequately drained.

- Internal walls should be smooth, waterproof, resistant to fracture, light colored and readily cleanable.

- Ceiling should be so designed, constructed, and finished as to prevent accumulation of dirt and minimize condensation, mould development, flaking, and should be easy to clean.

- Windowsills should be kept to a minimize size, be sloped inward at least 45 degrees and be at least one meter from the floor.

- All doors through which fish or their products are moved should be sufficiently wide, well constructed of a suitable materials and should be of a self-closing type.

- Stairs, lift cages and auxiliary structures should be so situated and constructed as not to cause contamination to fish

c. Control of environmental
- Premises should be well ventilated to prevent excessive heat, condensation, and contamination with obnoxious odor, dust, vapor, or smoke.

- A minimum illumination of 220 lux (20 foot candles) in general working areas and not less than 540 lux (50 foot candles) at points requiring close examination of the product should be provided and should not alter colors.

- An ample supply of cold and hot potable water and/or clean sea water under adequate pressure should be available at numerous points throughout the premises at all times during the working ours.

- When in-pant chlorination of water is used, the residual content of free chlorine should be maintained at no more than the minimum effective level for the use intended.

- Ice should be made from potable water or clean seawater and should be manufactured, handled and stored to protect it from contamination.

- Proper facilities for washing and disinfection of equipment should be provided.

- Drains should be of an adequate size, suitable type, equipped with traps and with removable grating to permit cleaning.

- A separate refuse room or other equally adequate offal storage facilities should be provided on the premises.

- Staff amenities such as lunchrooms and changing rooms or rooms containing shower or washing facilities should be provided.

- Adequate and conveniently located toilet facilities should be provided.

- Facilities should be available in the processing areas for employees to wash and dry their hands and for disinfection.