How should the laboratory conduct aseptic sampling?
Liquid sample
Liquid samples are relatively easy to obtain. Liquid food is generally stored in large tanks and can be continuously or intermittently stirred during sampling. For smaller containers, the liquid can be turned upside down before sampling to make it completely mixed. The samples obtained shall be put in sterilized containers and sent to the laboratory. The laboratory shall thoroughly mix the liquid again before sampling and testing.
Solid sample
The common sampling tools for solid samples include scalpel, spoon, cork drill, saw, pliers, etc., which must be sterilized before use. For example, milk powder and other foods that have been well mixed, the quality of their ingredients is uniform and stable, and a small amount of samples can be taken for testing; Bulk samples shall be sampled from multiple points, and each point shall be treated separately, and thoroughly mixed before testing; Meat, fish or similar foods should be sampled not only in the skin, but also in the deep layer, and care should be taken not to be contaminated by the surface during the deep layer sampling.
water sample
When taking water samples, it is better to choose a wide mouth bottle with a dust-proof grinding stopper.
If the sample is taken from the faucet, the inside and outside of the faucet should be wiped clean. Turn on the faucet to let the water flow for a few minutes, turn off the faucet and burn it with an alcohol lamp, turn on the faucet again to let the water flow for 1-2min, then connect the sample and fill the sampling bottle. If the purpose of the test is to trace the pollution source of microorganisms, it is suggested that sampling should also be taken before the sterilization of the faucet. The inside and outside of the faucet should be smeared with a cotton swab for sampling to detect the possibility of self pollution of the faucet.
When taking water samples from reservoirs, rivers, wells, etc., use sterile instruments or tools to take bottles and open bottle plugs. When taking samples from flowing water, the bottle mouth should be directly facing the water flow.
Packaged food
Small packaged food for direct consumption shall be taken from the original packaging as much as possible, and shall not be opened until testing to prevent contamination; Liquid or solid food packaged in barrels or containers shall be taken from several different parts with aseptic sampler and put into the sterilization container together; The samples of frozen food shall always be kept in a frozen state after sampling and before being delivered to the laboratory. Once the sample is melted, it cannot be refreeze, and it can be kept cool.
The standardization of aseptic sampling is the premise to ensure the accuracy of sample detection. Therefore, we should standardize the operation during sampling to ensure that pollution is eliminated from the source.
Post time: Nov-30-2022