Design and construction of food purification workshop

 
 
Requirements for clean rooms in food industry:
The clean room of food industry shall be constructed according to the principle of biological clean room
The processes that have aseptic requirements but cannot be subject to final sterilization and the processes that can be subject to final sterilization but have aseptic operation after sterilization shall be carried out in the clean production area

  Clean production areas with requirements for a good hygienic production environment shall include places for the storage and pretreatment of perishable food, ready to eat semi-finished products or finished products before final cooling or packaging, places for the pretreatment of raw materials, product potting and molding that cannot be finally sterilized, the exposed environment after final sterilization of products, inner packaging material preparation room and inner packaging room, as well as places for food production Processing places and laboratories to improve food characteristics or preservation

The pretreatment of raw materials (such as cutting, grinding, cooking, extraction, concentration and dilution) shall not use the same clean area as the production of finished products

The inspection room should be set up independently, and proper treatment measures should be taken for its exhaust and drainage
When there are air cleaning requirements for the sample inspection process, a clean workbench shall be set

  Clean rooms in the food industry shall be graded according to the requirements of food production for sterilization, dust removal and aseptic production

  The key control points, key areas and background areas of production in the clean room shall be defined and graded respectively
Reduce the area of high-level areas as much as possible

  Clean rooms in the food industry should be divided into the following four grades:
Class I clean operation area with high pollution risk
High pollution risk refers to the situation that the food is easy to grow bacteria, the preparation and filling speed is slow, the filling container is a wide mouth bottle, and the container must be exposed for several seconds before being closed under the condition of non final sterilization

The background environment of class II and class I area, or the clean operation area involving non final sterilized food with pollution risk second only to class I

Clean operation area with less important degree in class III production process

Level IV belongs to the area with general cleaning requirements of pre process

The temperature and humidity of clean rooms in the food industry shall comply with the following provisions

1
If the production process has special requirements for temperature and humidity, it shall be determined according to the process requirements
See Appendix B

2
When the production process has no special requirements for temperature and humidity, the temperature of class I and class II clean rooms shall be 20 ~ 25 ℃ and the relative humidity shall be 30% ~ 65%; The temperature of class III clean room shall be 18 ~ 26 ℃, and the relative humidity shall be 30% ~ 70%

The clean room of food industry shall adopt local purification method as far as possible to protect the key areas to achieve the required control parameters

The air purification system shall be equipped with three-stage filtration, which is located at the fresh air outlet, the positive pressure section of the fan and the air supply outlet

The air flow should be directed from the indoor polluted area

Vertical unidirectional flow should be adopted for indoor air distribution of class I clean rooms, vertical unidirectional flow with surrounding walls should be adopted for local class I clean rooms, and non unidirectional flow should be adopted for other classes of clean rooms

The ventilation times of clean rooms of different grades shall meet the following requirements:
Class II not less than 20 times / h
Class III not less than 15 times / h
Class IV not less than 10 times / h
No grade requirement: no less than 5 times / h
The fresh air volume shall not be less than 40m3 / h per person, and shall also meet the needs of air exhaust and maintaining positive pressure

  Relative negative pressure shall be maintained in the polluted room
Rooms with high pollution control requirements should maintain relative positive pressure

 
Table 10
4
5 filter replacement cycle

category	replacement cycle
fresh air inlet filter	clean once a week or so, and the cycle in windy and sandy areas is shorter (except those that can be replaced automatically)
coarse filter	1 ~ 2 months (excluding those that can be replaced automatically)
medium efficiency filter	2 ~ 4 months (excluding those that can be replaced automatically)
sub high efficiency filter	1 year
high efficiency filter	3 years