Reference material of Staphylococcus aureus Count in food

Product number: 359095

Production batch:20210621

Setting value date: June 15, 2021

Staphylococcus aureus is one of the important pathogenic bacteria causing bacterial food poisoning, and is the most common pathogenic bacteria in animal and human purulent infections. It may exist in excrement, so food, especially milk and dairy products, have many opportunities for contamination. This standard material can be used for method validation of quantitative detection of Staphylococcus aureus in food and quality control of microbiological laboratory measurements, and can also be used for growth rate evaluation of selective medium for Staphylococcus aureus, Providing metrological traceability assurance for the reliability of evaluation results

1. Sample preparation

Select and culture Staphylococcus aureus (ATCC 6538) ， and dispense the bacteria suspension into penicillin bottles by pasteur pipette, then make it freeze-dried and sealed.

2. Traceability and value setting method

The reference material is determined by multiple organizations using the spreading method. After 10 times series dilution of the standard substance, the number of colonies on the medium plate is counted, and the total number of colonies is calculated by formula, and the unit of measure is CFU/mL(CFU, colony forming unit Colony-Forming Units). By using quality volume etc measurement instruments that is verified and calibrated, and the quantitative measurement methods which meet the requirements of metrology characteristics, it is ensured that the measurement value of this reference material can be traced back to the basic unit of entity number “1” and the national legal unit of measurement “L”.

3. Characteristic value and uncertainty

The uncertainty of the setting value is obtained by the combination of uncertainty components introduced by the setting method, balance, pipette, dilution factor, uniformity and stability.

4. Uniformity and stability evaluation

According to the JJF1343 national metrology technical specifications (equivalent ISO guide 35), use staphylococcus aureus spread plate method， and evaluate the uniformity of the sample according to the principle of random sampling. The results of variance analysis show that the uniformity of the sample is good; Using the same measurement method, the stability of the sample is evaluated according to the principle of first density and then sparse. The trend analysis results show that it can be stored stably for a long time at -20 ℃, for 7 days at 4 ℃ and dry ice transport is recommended. The reference material is valid for 12 months from the setting date. We will continue to track and monitor the stability of the standard substance. If changes in the value are found during the validity period, the user will be notified in time.

5. Packaging, storage and usage

1. packaging and preservation: the reference material is packed in 3ml penile bottles and sealed after freeze-drying. It is shipped on dry ice. Upon receipt, check if the dry ice is exhausted or not. Then put it in a refrigerator at -20 ℃.

2. use: the reference material should be used up at one time after opening the bottle. Before use, take it out of -20 ℃ and balance it at room temperature for 10 minutes. accurately weigh (1.09±0.01) g with a balance(20 ℃) of sterile distilled water to re-dissolve the freeze-dried reference material.

3. the reference material contains microorganisms. masks and latex gloves should be worn before handling. Pay attention to protect yourself during the handling, avoid inhalation or direct skin contact. After use, the remaining samples, packaging bottles, sampling tips and other consumables should be autoclaved according to biological pollution waste.

6.References

[1] GB 4789.10-2016, National Food Safety Standard Food Microbiological Inspection Staphylococcus aureus Inspection [S].

Statement

1. the reference material is only for laboratory research and analysis and testing. Complaints arising from improper use or storage by users shall not be liable.

2. Please check the variety, quantity, packaging and certificate immediately upon receipt. The relevant compensation is limited to the reference material itself and does not involve any other losses.

3. the reference material is shipped with the certificate stamped”"special seal for certified reference materials of Beijing Beina Chuanglian Biotechnology Research Institute". We will not accept any complaints if the certificate can not be provided. Please keep this certificate properly.

4. For more application-related information, please contact the technical department.

Beijing Beina Chuanglian Biotechnology Research Institute

Technicians: 400-6699-833