Construction project for a new plant: Basic aspects related to the hygiene of facilities

Hygiene is essential to achieve safe and good quality food. Hygiene practices must be efficient at all stages of the food chain, from production to consumption, in order to avoid errors that may cause foodborne diseases or alterations that reduce their useful life.

In the European Union, health regulations on food have a strongly preventive nature, enhancing all aspects that help preventing diseases transmission.

Moreover, the increasing limitations in the use of certain preservatives and the restriction to very low doses of authorised preservatives contribute, in a higher degree, to implementing hygiene standards of a preventive nature that result in in the establishment of application guidelines to enable performing a clean job, without additional contamination, and a strict control of compliance. Hygiene should be considered as a very important stage of the production process. Implementing a standardised work protocol that detects the existing deficiencies and offers solutions to the problems that have occurred, will guarantee a correct and continuous sanitary level of the facilities, thus safeguarding the correct hygiene of the products manufactured in them.

This trend is currently being implemented in food industries in general, where, in addition to analysing the finished product, there is a control of the set of processes involved in manufacturing that may interfere with sanitary hygiene quality.

A series of rigorous measures based on the following three points need to be applied in food industries:

  • Food products must be of an excellent quality.
  • Personnel must be in good health and have a clean and neat appearance, being informed and educated on the hygiene rules that must be followed during the handling of the products they manufacture. The technological processes used must be appropriate.
  • The premises and equipment must be kept in good hygienic condition. The correct hygienic condition of the facilities must consider both the cleaning operations carried out frequently and properly, and the development and design of the equipment. All equipment surfaces should be readily accessible for these cleaning operations. If some surfaces cannot be accessed to be cleaned and disinfected, their effectiveness will be significantly reduced, as microorganisms will survive, and nearby surfaces will be rapidly re-contaminated.

In general, there are three intangible principles that should not be overlooked in any case:

  1. Clean and dirty areas must be significantly separated. Product and people circuits must be as short as possible.
  2. Always remember that products must have progress forward at all times. Under no circumstances the following cases will be acceptable: products moving backwards, crossing between products and residues, crossing between the naked product and the packaged product, and crossing of a raw material and a finished product.
  3. Potential for expansion must be reserved for each function:

The facilities being compact means that circuits are short, therefore this solution must be sought. To this end, the circuits must be as straight as possible.

It may be useful to consider the prevailing winds and the factory orientation on the ground to take them into account. The possibility of facilitating cross contamination from dirty to clean areas caused by the internal winds of the plant should always be avoided.


A. The hygiene programme

The company’s management team must establish a Hygiene Programme that guarantees compliance with the various points regarding the cleaning and disinfection of premises, equipment and tools, providing all necessary means for correct compliance.


B. Sanitation plan monitoring and control

Community regulations require companies to verify the effectiveness of cleaning and disinfection procedures by undertaking regular checks of the general hygiene of production conditions. These controls will refer to the tools, facilities and machinery in all production stages and, if necessary, to the products. The verification procedures are:

  1. Visual inspection of apparent cleanliness.
  2. Microbiological controls by analysing samples from the surfaces of the facilities and utensils, and the environment. Since the control periodicity and the allowed microbiological counts are not established, it is recommended that each company sets its “hygiene standard” as a conclusion of the repeated sampling and analysis and to progressively increase its level.
  3. Microbiological controls in or on the products once all handling operations have been performed.
  4. Sampling of the work flow, trying to determine the microbial levels in or on the samples of food products obtained after each stage of the transformation process.
  5. Control of organic matter waste (ATP).
  6. Detection of biofilms using specific matrix staining (TBF300)
  7. Personnel training programme

Companies must ensure food handlers are trained on food hygiene, in accordance with their work activity. In this sense, it would be interesting to train a person specialised in plant hygiene (Plant Hygienist), hiring companies specialised in this type of training.


C. Sanitation programme

Sanitation refers to the treatment that reduces microbial population to levels that are considered not to be detrimental to public health. The Sanitation Programme or Plan considers cleaning and disinfection operations jointly. This programme should apply from the reception of the raw material to the final product, through the various intermediate handling stages. To be effective, it must be developed by specialised personnel, responsible for cleaning and hygiene issues of the production plant and equipment.

The sequential procedure to prepare the Plan or Programme would be:

  1. Inspection of the facilities, knowing the product to be manufactured, material and condition of the surfaces or supports to be sanitised, nature and degree of dirt, as well as the location of the premises and set-up of the machinery.
  2. Physical and chemical microbiological analysis of the water to be used for cleaning and disinfecting.
  3. Study of the necessary means to undertake the cleaning and disinfection works, considering the personnel assigned to clean, number of hours and cleaning schedule, systems and equipment available for cleaning and disinfecting the facilities, equipment dimensioning depending on the surface to be cleaned, number of satellites, meters of hoses, studies of load losses that hinder the correct cleaning, etc.
  4. Agree on the type, application, frequency and dosage of chemical products used with specialists in the sector, always seeking to optimise these processes.
  5. Set a C&D routine for each area or machinery and for each cleaning operator.


D. Contamination origin and classes in the industry

Food production centralisation and collective increase require manufacturing, handling, conservation and transportation of increasingly important quantities of raw materials and packaged products and the continuous and massive movement of people. These have caused eating disorders risks having significantly increased.

It is important to address the cleaning and disinfection issue as a whole, treating each possible contamination source (surface, air, compressed air, personnel hands and their clothes) with detersive and antimicrobial action products.

Contamination classes and routes. The main ones are:

  • Human factor
  • Insects, rodents and birds
  • Water
  • Air and dust
  • Raw material
  • Tools and equipment (surfaces, facilities)


E. Aspects to consider about the facilities to undertake a hygiene programme in the food industry

Facilities characteristics:

There are many aspects that must be considered to control correctly a hygiene programme that covers all points of interest. Hygiene programmes and work organisation systems must take into account the division of food production facilities in dirty and clean areas, or in dry and wet areas, according to the type of processing, each with its own operating conditions. Any cross-contamination between operations, from the material, aeration or personnel should be avoided. It is imperative that at the end of each work phase, or at least once a day, facilities are cleaned and disinfected, exhaustively controlling the surfaces that will later be in contact with perishable products. The hygiene programme should be designed based on a risk study of the facilities and the processes. Several factors must be considered to be able to diagnose the correct hygienic quality of the facilities:

  • Site selection.
  • Water quality.
  • Waste water.
  • Design and construction of the facilities, equipment and accessories:

> Premises layout: the work areas must be clearly defined, taking into account that the shape of the manufacturing plant will be conditioned by the process developed in it. It should be designed in such a way that the product flow always goes from the most contaminated area to the least contaminated areas, since the only way to avoid secondary contamination is by ensuring the principle of separation of product circuits, without crossings or returns in the production lines.

> There must be separations between facilities with different functions. This will create exclusive spaces separated from the rest of the facilities for C&D products, storage of containers and packaging, and for waste.

  • Solid waste disposal.
  • Materials: The materials used for the industry must be innocuous and not transmit harmful properties to food products or change their organoleptic characteristics. The most commonly used materials in the food industry are stainless steels. These types of materials have a high resistance to corrosion and are easy to clean and disinfect. Surfaces in contact with food must be non-toxic and non-absorbent, non-porous and non-corrosive. Out of the several materials used, stainless steel is the most suitable for surfaces that come into contact with food, such as equipment.

The materials surfaces will have a minimum roughness, and the different parts of the equipment need to be easily inspected. Otherwise, they must be easy to dismantle to allow inspection, so they will be closed using joints. Condensation, washing and rinsing waters will drain freely outwards, avoiding leaks.

  • Floors: They must be waterproof, abrasion-resistant, incombustible, easy to clean and disinfect, antacid, anti-slip and with a slope to facilitate the extraction of water and other liquids.
  • Drains: It is recommended to have a surface drain for every 35m2 of surface. They should enable cleaning and sanitising the floor so that liquid waste is quickly removed. They should be equipped with grids and sumps to stop solid waste and be easy to clean.
  • Walls: They must be easy to clean and wash. Likewise, they must be covered with waterproof material and have a smooth surface. It is advisable to use a light colour for brightness. The wall-ceiling and wall-floor joining areas must be curved.
  • Windows and doors: They must be kept clean. Exit doors must open outwards and have an automatic closing system. Door and window frames must guarantee a hermetic closing. In production areas, where vapours can occur, windows should be elongated, close to the ceiling and equipped with extractors. Windows inner ledges should always be avoided if possible. In any case, if there are any, they must have a minimum inclination of 45º.
  • Ceilings: They should be kept clean and in good condition. It is important to have a system to eliminate vapours and humidity, especially in areas where food is directly handled. Ceilings should be smooth and washable.
  • Columns: They should have a rounded geometry, easy to clean and be smooth.
  • Cabinets: They must be made of stainless steel. The upper part will have an inclination of 45º or greater in order to avoid the accumulation of dust and dirt. The cabinets will never reach the floor, leaving a clearance of 40cm to facilitate cleaning.
  • Machinery and equipment: In general, the design, construction materials used, and equipment installation methods should be chosen in such a way that they contribute to cleaning and disinfection. Wet cleaning is advisable whenever possible.
  • Electrical installations: Each element integrating the electrical equipment must be clean and remain closed to prevent insect and rodent nesting or any other kind of dirt. The sealing of electrical appliances must be guaranteed in food handling areas where hygienic practices are conducted using water.
  • Washbasins and foot baths: They are necessary to maintain the highest possible standards of hygiene. Washbasins must have hot and cold water, or pre-mixed water at an appropriate temperature, a detergent product, and single-use towels. In addition, it should not be possible to open the taps using the hands. Regarding foot baths, they should be in accesses to clean areas to avoid the contamination present in shoes soles.
  • Changing rooms and sanitary services: Access doors will have automatic closing and should never be near food handling areas to avoid air contamination. Using double doors and a negative air pressure system is advisable to avoid this type of air contamination. In addition, they will be constructed with easy-to-clean materials.
  • Ventilation: In food processing areas, it is advisable to work with a positive pressure ventilation system to prevent the easy entry of contamination from the outside. Proper ventilation will prevent wall and ceiling condensation causing contamination by bacteria and moulds, thus reducing the possibility that these microorganisms reach food contact surfaces. In addition, it will prevent excess heat, unpleasant odours and keep the accumulation of dirt on walls and ceilings to a minimum. The extraction fans outlets must have gratings to stop insects, rodents and birds from entering.
  • Lighting: A good and conveniently protected lighting system is essential to keep the correct hygienic guarantees in the facilities, so in case it breaks, no debris or dirt could contaminate the food. In addition, it must be attached to the ceiling or walls in a way that guarantees an easy and comfortable cleaning, preventing dirt accumulation. The use a specific light intensity depending on the work area is recommended.


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