Pasteurization is effective at inactivating which avian influenza strain, according to the material?

• A. H5N1
• B. H1N1
• C. H7N9
• D. H9N2

Answer: (A)

Pasteurization inactivates many pathogens by heating them enough to break their structure, and enveloped viruses are particularly vulnerable because their lipid envelope is heat-labile. Influenza viruses have this envelope, so the heat disrupts the envelope and denatures surface proteins, preventing the virus from binding to and entering host cells. This is why enveloped viruses are generally more heat-sensitive during pasteurization than non-enveloped ones. The material you’re studying specifically notes that the avian influenza strain inactivated by pasteurization is H5N1, reflecting the pattern that enveloped influenza viruses lose infectivity under standard pasteurization temperatures.