Hygiene Validation for SARS-CoV-2 in the Environment

Coronavirus Disease 2019 (COVID-19) is an infectious disease caused by the most recently discovered coronavirus SARS-CoV-2, which may lead to severe acute respiratory syndrome (SARS). The disease can spread from person to person through several pathways: including breathing in droplets from a person with COVID-19 who coughs or exhales, or touching contaminated objects or surfaces. Studies suggest that coronaviruses (including preliminary information on the COVID-19 virus) may persist on surfaces for a few hours or up to several days. This may vary under different conditions (e.g. type of surface, temperature or humidity of the environment). At present, effective methods commonly used for environment disinfection and sterilization include spraying or wiping the surface of objects with chlorine-containing disinfectant or 75% ethanol, heating at 56℃ for 30 minutes, etc.

Eurofins food testing laboratories in China actively developed and validated the hygiene validation method for SARS-CoV-2 in the environment through Reverse Transcription-Polymerase Chain Reaction (RT-PCR). This method refers to and conforms to < Laboratory testing technical guidelines for COVID-19> by the Chinese Center for Disease Control and Prevention. Generated from the extracted RNA by reverse transcription through RT-PCR, the virus-specific cDNA is amplified in the solution of polymerase, characteristic primers, probes and dNTP. Their fluorescence signals are then released allowing determination of the existence of the virus through qualitative and quantitative analysis. The procedure reliability of the swab, virus extraction, purification, reverse transcription and amplification, etc. is monitored by quality control materials so that false-negative results can be effectively avoided.

ABOUT THIS SERVICE

The service aims to help manufacturers to validate the effect of disinfection and sterilization of the production environment including production area, office and public regions etc. and provide effective evidence to prove the inexistence of SARS-CoV-2 in the environment. It can further guarantee employee health and product safety and to help manufacturers resume import and export business activities.

* Safety Commitment by the customer is a MUST before performing this test.

Method Principle: ORF1ab and N genes are selected as the specific target gene fragments of SARS-CoV-2. Specific primers and fluorescent probes are designed for multiple RT-PCR amplification.

Result Interpretation:

• Positive control: significant amplification curves of the target ORF1ab and N genes , Ct value ≤32,  whereas a significant amplification curve of the procedure control, Ct value <40.
• Negative control: no significant amplification curve of  ORF1ab and N genes, but  a significant amplification curve of the procedure control target gene, Ct value <40.
• Positive sample: the target ORF1ab and N genes have significant amplification curves and Ct value <40, with or without a significant amplification curve of the procedure control,  if retest result keeps the same, the conclusion is positive.
• Negative sample: no significant amplification curves for  ORF1ab and N genes and their Ct value >40, simultaneously with a significant amplification curve of the procedure control gene and its Ct value < 40.