Collection and preservation of samples
The collection of samples, as a fundamental step in food inspection, must be carefully selected. During sampling, the production date, batch number, representativeness, and uniformity of the samples must be clearly defined, and the amount collected must meet the requirements of food hygiene quality and inspection. In general, samples should be divided into three parts for inspection, retesting, and reference. Bulk samples should not be less than 500g per part. Food samples collected should be placed in hard glass bottles or polyethylene products. After the sampling is completed, a sampling record needs to be filled out, which is equivalent to a pass. Samples without sampling records cannot undergo food inspection.
Selection of instruments and reagents
Different inspection samples require the selection of corresponding instruments, so the choice of inspection instruments is also very important. For instruments that can be calibrated, regular calibration should be carried out, and homemade distillation equipment should ensure airtightness. In addition, it is necessary to regularly maintain the instruments. For example, if the balance is not maintained for a long time, if the weights or trays are worn or rusted, it will cause significant system errors in the balance, which will directly affect the results of subsequent inspections.
Reagents are substances that come into direct contact with and react with samples, so their selection should be particularly careful. Reagents also have a shelf life, and for different reagents, their shelf life must be clearly defined. For example, metal element standard solutions can be stored for one year, and standard titration solutions require calibration every two months. Some reagents will undergo qualitative changes and their purity will be affected if they are exposed to air or sunlight for a long time. Once any changes are found in the reagent or its concentration cannot be determined, the reagent needs to be replaced and must not be used indiscriminately.
Determination of Inspection Methods
Inspectors should test the samples according to the inspection methods specified in the product standards. Sometimes there may be multiple methods, so the actual situation should be considered, such as the nature of the sample, the inspection conditions and environment at that time, and the instruments available. If there are objections to the results obtained after using a certain method, arbitration can be chosen. It is necessary to flexibly choose different methods for testing. If chemical analysis cannot be used, instrument analysis should be used. If the components in the sample are different, different detection methods corresponding to each component should be used.
Functional requirements for testing personnel
The process of inspection and the recording of results require the participation of inspection personnel, which requires them to have high professional skills and qualities, and be able to complete the entire inspection process conscientiously and responsibly. For example, it is necessary to operate carefully and record the results carefully, including all data, information, and phenomena related to product testing, because any small detail may ultimately affect the accuracy of the testing.
Food safety, as a topic of common concern to the whole society, the accuracy of its inspection will directly affect the safety of food, so every inspection step must be carried out with great caution. We need to pay attention to controlling errors in every inspection step, such as sample collection and storage, selection of instruments and reagents, determination of inspection methods, functional requirements of testing personnel, and selection and control of monitoring environments. Only by reducing errors in each step can we obtain a relatively good food inspection result.