Discussion on the performance of clean clothes, disinfection and sterilization effect and verification of service life
Clean clothes are special work clothes with dust-free, dust-proof and anti-static properties suitable for the electronics, optical instruments, medicine, bioengineering, precision instruments and other industries. The clothing is generally a composite spinning anti-static fiber with embedded conductive yarn. Aseptic work clothes (referred to as sterile clothes) refer to the clean clothes used in the local 100-level environment under 10,000. The human body is the largest source of pollution in the clean room, and clean clothing is the necessary protective measure for personnel to enter the clean area, which plays a vital role in maintaining the clean room environment and personnel protection.
The "Detailed Regulations for Sterile Medical Devices" stipulates that: production enterprises shall establish requirements for personnel clothing and form documents. Production enterprises shall formulate management regulations for clean and sterile work clothes. Clean overalls and sterile overalls must not fall off fibers and particulate matter. Sterile overalls should cover all hair, beards and feet, and retain body exfoliation. The "Good Manufacturing Practices (2010 Revision)" also requires that the overalls and their quality should be compatible with the requirements of the production operation and the cleanliness level of the operating area, and the clean clothes are specified according to different cleanliness levels: C, D Work clothes should be required to avoid contaminants or fibers that are not taken out of the clean area; A/B work clothes should be sterilized joint work clothes, do not fall off fibers or particles, and can retain particles emitted by the body. It is therefore necessary to verify the clean clothes to ensure they meet the requirements of clean, anti-static and microbiological. The following sections discuss the validation of clean clothing in terms of performance, disinfection and efficacy, and duration of use.
Performance evaluation project for clean clothes
As a branch of anti-static clothing, in addition to the requirement to control static electricity, clean clothing also requires clean performance - the clothing itself does not dust, and at the same time can block the emission of human particles to the outside world. The detection of the performance of clean clothes has been in a blank state in China, there is no standard basis, and there is no testing mechanism. IEST-RP-CC003.3 "Clean Room and Related Controlled Environment: Clothing Elements", which is widely recognized in the industry, is a recommended standard for the performance evaluation of clean clothes by the American Environmental Science Association. The main contents of this standard include purification service system and pollutant control, fabric parameters and characteristics, test methods for fabric cleanliness, test methods for cleanliness of clean clothes, proper use of clean clothes, and maintenance of clean clothes.
Most of our current clean clothes are produced according to GB/T 12014-2009 "anti-static clothing" standard, emphasizing anti-static performance, but no clean performance and microbiological requirements. In fact, after the clean clothes are cleaned and sterilized, the material of the clothes will age, the fibers will easily break and produce particles, and the local filtration efficiency of the clean clothes will be reduced. With the use of clean clothes, its clean performance and anti-static performance will be reduced, so the performance evaluation of clean clothes is mainly in terms of clean performance and anti-static properties.
Performance testing methods and acceptance criteria for clean clothes
Since there is no testing standard for clean clothes, the company can select the test items when it is tested. The specific project recommendations are given below.
1. Clean performance: The basic requirements for clean performance are high filtration and low dust generation. To evaluate the clean performance, it is necessary to start from the two aspects of dust-free and dust-free. The dust-free means that the garment itself does not dust. The dust filter refers to the clean clothes blocking the outward diffusion of human particles.
Dust-free: The dusting performance of the clean clothes itself is generally evaluated by the Helmke roller (Fig. 1). The work clothes are placed in a closed stainless steel drum, tumbling and rubbing according to a certain procedure, and the air in the drum is sampled by a dust particle counter. Calculate the number of particles (particle size range ≥0.3μm) produced by the sample per unit time, which should be ≤500/min.
Dust filter: The particle filtration efficiency test is to clamp the clean clothes on the fixing device (the fabric air particle filtration efficiency test bench), and the vacuum pump is used to extract the air perpendicular to the sample, so that the particles of the specified size pass the sample under a certain concentration and pressure. The dust particle counter measures the number of particles in the space at both ends of the sample, and calculates the filtration efficiency based on the result, which should be ≥50% (particle diameter 0.5 μm).
2. Anti-static performance: The anti-static performance of the clean clothes can be easily judged by the heavy hammer surface resistance meter (Fig. 2). The principle is to calculate the resistance per unit area of the sample between the electrodes by applying a voltage on the ring electrode, which is essentially to test the area resistance of the fabric. According to the provisions of GB/T 24249-2009 "Anti-static clean fabric": qualified clean clothes should have a small resistance (1 × 105 ~ 1 × 1011 Ω / □ within a certain range), the resistance value is stable.
Verification of disinfection and sterilization effect of clean clothes
After cleaning, clean clothes should be disinfected or sterilized according to the requirements of use. Generally, clean clothes of 100,000 and 300,000 grades can be disinfected, while sterile clothes used in clean rooms of grades 10,000 and above need to be sterilized. Disinfection can be treated by a disinfection cabinet. If disinfection with a liquid disinfectant is used, the residue of the disinfectant should also be considered; sterilization treatment is usually performed at 121 ° C for 30 min.
The acceptance criteria for clean clothes sterilization can be referred to the provisions of GB/T15980-1995 Sanitary Standards for Disposable Medical Products: the acceptable standard for the number of bacteria on the surface of clean clothes is ≤20cfu/cm2, and the number of bacteria on the surface of the sterile clothes is acceptable. Standard ≤ 10 cfu / cm 2 .
Disinfection and sterilization test procedures for clean clothes:
Wipe recovery test: Take 3 sets of the same fabric of clean clothes, select the area of 10cm × 10cm, and determine the wiping recovery rate of Staphylococcus aureus liquid, not less than 70%.
Wiping test: The sterilized specification plate with an inner diameter of 5 cm×5 cm was placed in the neckline, cuff, and chest of the cleaned clothes after sterilization, and four parallel samples were taken with cotton swabs immersed in sterile saline. The agar medium was used for pour culture, and the number of bacteria was cultured at 30-35 ° C for 48 hours, which should meet the requirements.
The expiration date of the cleansing and sterilizing service is its safe use period, which must be verified by verification. There is data showing that the sterilized clean clothes are stored in the Class 10,000 clean area and can be stored for 7 days. Considering the risk, in general, the sterilization service should be valid for no more than 2 days, and the disinfection service can be set for 7 days. The surface microbiological verification can be carried out according to the above method in different storage periods.
Determination of the service period of clean clothes
The effectiveness of cleansing clothes decreases with time of use. The life of clean clothes involves many factors, including the way the clothes are worn, the way they are washed, the way they are sterilized, and the way they are stored. The average number of cleanings is more than 100 times. Enterprises can test the washed or used clothing according to their experience and actual production conditions to see if their indicators meet the requirements. The replacement cycle recommended by the cleansing manufacturer is usually one year. It is best to follow the verification results, and it is best to confirm the service life after the risk assessment.
Re-verification of clean clothes
Clean clothes should be re-verified under the following conditions:
Clean cleaning process, disinfection and sterilization methods (such as cleaning agents, sterilization and sterilization conditions, etc.);
When replacing cleaning and sterilizing equipment, etc., affecting the quality of cleaning, disinfection and sterilization of clean clothes;
When the cleansing manufacturer replaces or replaces the fabric;
When GB/T 15980 and other related standards are changed;
The routine revalidation cycle for the disinfection and sterilization effect of clean clothes is generally 2 years.
In short, the verification of medical cleansing clothes can not only consider microbial indicators, but also combine the product's process characteristics, consider the clean function of clean clothes, and establish a suitable period of use from the perspective of risk assessment to ensure the quality of pharmaceutical products.