What are the precautions in the construction of purification workshop, a food processing factory?

Matters needing attention in the construction process of purification workshop in food processing plant

The core principle of purification workshop construction of food processing plant is to ensure food safety, prevent and control microbial contamination, and conform to the hygienic standard of food production. It needs to be strictly controlled from four dimensions: pre-construction planning, construction process control, cross-operation protection and post-construction cleaning acceptance. The specific precautions are as follows:

I. Matters needing attention in the planning stage before construction

The construction plan for compliance plan review shall be strictly based on the General Hygienic Standard for Food Production (GB 14881) and the corresponding special standards (such as GMP standard for dairy products), and the design of clean classification (10,000-level and 100,000-level), functional division (raw material pretreatment area, aseptic filling area, finished product packaging area, etc.) and one-way flow of people and logistics shall be defined. The plan shall be reviewed and approved by relevant food and drug supervision departments or third-party compliance agencies before construction. Confirm the isolation between workshop site selection and surrounding environment in advance, stay away from dust, odor, sewage and other pollution sources, and avoid the impact of external environment on workshop cleanliness.

Material selection and inspection All materials entering the workshop must meet food-grade safety standards, and materials containing harmful substances such as formaldehyde and heavy metals are prohibited:

304 stainless steel plate and food-grade color steel plate are preferred for the enclosure structure, and the surface is required to be smooth and seamless without dead ends; Epoxy resin self-leveling or polyurethane mortar shall be selected for the ground, which shall have the characteristics of acid and alkali resistance, high-pressure water gun washing resistance and anti-skid.

Ventilation pipes, clean doors and windows, floor drains and other accessories should be made of stainless steel, and sealing strips should be made of food-grade silicone to avoid dust accumulation, water seepage and harmful substances precipitation.

Check the test report before the materials enter the site, and check whether the materials and specifications are consistent with the design by sampling. Unqualified materials are strictly prohibited from entering the site.

The construction team and tools are prepared to choose a team with the qualification of food purification workshop construction, and the construction personnel need to receive the training of food safety and clean construction specifications in advance. Prepare dust-free construction tools (such as stainless steel tools, dust-free cloth and vacuum cleaner), and all tools shall be cleaned and disinfected before entering the site; A dressing room and a hand washing and disinfection pool shall be set at the entrance of the workshop, and the construction personnel shall wear clean clothes, shoe covers and gloves before entering the construction area.

Second, the construction process control matters needing attention

Construction of enclosure structure: When strictly controlling the sealing property and splicing flatness of color steel plate or stainless steel plate, double sealing of sealing strip and neutral silicone sealants shall be adopted to ensure that there are no gaps and bubbles in the splicing seam and prevent dust and microorganisms from hiding; The junction of the wall, floor and ceiling needs to be arc-shaped (fillet radius ≥50mm) to avoid the formation of sanitary dead angle. Door frames and window frames shall be installed horizontally and vertically, and the joints with the wall shall be filled with foaming agent and sealed with glue. After installation, test whether the switch is smooth and whether the sealing strip is tightly attached. Floor drain installation should be carried out in strict accordance with the slope (the ground slope is 1%-2%) to ensure smooth drainage; The floor drain must be equipped with a water seal device and a detachable filter screen to prevent sewer odor and bacteria from flowing backwards.

Construction of ventilation and purification system: to ensure the air distribution and filtration effect, the inner wall of ventilation pipeline should be cleaned before installation to remove oil and dust, and sharp corners should be avoided during installation to reduce dust adhesion; The pipeline connection is sealed with flange to prevent air leakage. HEPA should be installed after the building envelope of the workshop is completed and the interior is cleaned. Before installation, the integrity of the filter should be checked, and after installation, leak detection tests should be conducted to ensure no leakage. The airflow organization should follow the principle of upward delivery and downward return, and the air supply outlet should avoid the direct exposure area of food to prevent the water loss or pollution of products caused by direct air blowing; The pressure difference in different clean areas should be set in advance (the positive pressure in clean areas is 10-20Pa relative to that in non-clean areas), and it should be adjusted and stabilized by variable frequency fans.

Installation of water, electricity and equipment: to avoid pollution risks, wires and water pipes should be concealed (hidden in the wall or ceiling), and exposed pipelines should be protected by stainless steel sleeves, and the joints should be sealed to prevent condensation water leakage and dust accumulation. Disinfection equipment (ultraviolet lamp, ozone generator) should be reasonably arranged according to the production area, and the installation height of ultraviolet lamp should be 2-2.5m from the ground to avoid irradiation to the skin and eyes of operators; The ozone generator needs to be equipped with a timing device to ensure adequate exhaust after disinfection and the residual concentration meets the safety standards. When installing equipment, keep a certain distance (≥30cm) from the wall and the ground to facilitate cleaning and maintenance; The surface of equipment in contact with food should be smooth and burr-free, and after installation, it should be cleaned, disinfected and put into trial operation.

Three, crossover operation and environmental protection considerations

Construction shall be carried out in different zones to avoid cross-contamination. The clean zone shall be constructed from high to low (sterile filling room first, then raw material pretreatment room). The high clean zone shall be temporarily isolated with colored steel plates, and construction personnel and tools in the low clean zone are prohibited from entering. Different types of work (such as civil engineering, ventilation, water and electricity) need peak-shifting operation to avoid dust and noise pollution caused by simultaneous construction; Operations that generate dust and odor such as cutting and welding need to be moved outside the workshop. If they must be operated in the workshop, local ventilation and dust removal should be done.

Cleanliness maintenance in the construction process: After the construction every day, it is necessary to clean the floor and wall with a vacuum cleaner and a dust-free cloth, and clean up the construction waste in time. It is strictly forbidden to pile up sundries in the workshop; The temperature and humidity in the construction area should be controlled within a reasonable range (temperature 18-26℃, humidity 40%-60%) to prevent mold breeding. It is forbidden to use oily paint, glue and other volatile and harmful substances in the workshop. If necessary, it is necessary to use food-grade environmental protection products and strengthen ventilation.

IV. Precautions for cleaning and acceptance after construction

After the overall cleaning and disinfection construction is completed, it is necessary to carry out three-level cleaning: first, wash the ground and wall with high-pressure water guns; Wipe all surfaces with neutral detergent; Finally, use disinfectants (such as peracetic acid and sodium hypochlorite) for all-round disinfection to ensure no residual pollutants. The high-efficiency filter needs to be tested for leakage again, and the ventilation system runs continuously for more than 24 hours to discharge the residual odor and dust in the room.

The compliance acceptance invites the third-party testing organization to test the cleanliness level, microbial quantity, pressure difference, temperature and humidity of the workshop, and the test results shall meet the design requirements and national standards. Check whether the construction materials (such as material inspection reports, concealed works records and equipment debugging records) are complete, and put them into a book for filing as an important basis for subsequent food production licenses.

After the protection after delivery is qualified, the protective film shall be pasted on the ground, wall surface and equipment surface to prevent the subsequent equipment from entering the site and production debugging. Establish workshop maintenance system, define filter replacement cycle and cleaning and disinfection process to ensure long-term stable operation of clean workshop.