Aljosa Trmcic

Highly Pathogenic Avian Influenza (HPAI) is causing a bit of trouble for all of us dairy folks and the way information is slowly trickling in is causing a lot of headaches. In these times when the situation is still developing and there is still a lot of unknowns, we have to rely on what we do know and be careful about interpretations of what we don’t know. Here are some facts that we do know and some that we don’t:

• Infected cows that develop symptoms are segregated from the rest of the herd and the milk collected from these cows is diverted and destroyed. The prevalence of pre- or asymptomatic infections in cows and viral shedding is still being studied.
• If HPAI virus is present in raw milk it is expected to be inactivated by milk pasteurization as less heat intensive pasteurization practices used in other foods have been shown to effectively reduce HPAI viral loads.
• Raw milk represents a public health risk; however, the risk of bacterial pathogens in raw milk is much greater compared to risk of HPAI.
• Virus remnants (e.g., genetic material) from inactivated HPAI virus can still be detected in pasteurized milk using PCR; however, this presence does not represent a public health risk because only live, infectious virus can cause an illness. Studies that found PCR positive samples of pasteurized milk and dairy products, did not find live infectious virus in any of the tested samples.
• There are no documented human cases of HPAI being contracted from properly cooked or pasteurized foods.
• Data specific to aging of raw milk cheese is very limited; based on environmental persistence studies it would be hard to predict if 60-day aging required for raw milk cheese would be sufficient to inactivate all HPAI virus during aging. Regardless of the HPAI risk, the risk of bacterial pathogens is higher in raw milk cheese compared to pasteurized milk cheese.

If you need to share the information on what we do know and what we don’t, make sure you use the resources we made for you:
1. Factsheet in English: Highly Pathogenic Avian Influenza (HPAI) Factsheet for the Dairy Industry and Dairy Consumers.
2. >Hoja Informativa: Virus de la Influenza Aviar Altamente Patogénico (HPAI, por sus siglas en inglés) Hoja Informativa para la Industria Láctea y sus Consumidores.
3. Recording of Dairy Foods Virtual Office Hours: Update – HPAI in Cattle – Current Status and Testing Details (May 1st, 2024)
4. Recording of Dairy Foods Virtual Office Hours: What Dairy Industry/Consumers should know about the Highly Pathogenic Avian Influenza Virus (April 3rd, 2024).

Virus or no virus Cornell’s Dairy Foods Extension is here for you.