tetano
Editor, Senior Moderator
Food Microbiol
. 2026 Aug:137:105015.
doi: 10.1016/j.fm.2025.105015. Epub 2025 Dec 26.
The impact of acids, pH, and incubation time on avian influenza virus persistence in raw milk
T L Harrell[SUP] 1 [/SUP], A Shwani[SUP] 2 [/SUP], D L Suarez[SUP] 3 [/SUP]
Affiliations
In March 2024, highly pathogenic avian influenza virus (HPAIV) clade 2.3.4.4. b H5N1 was detected in dairy cattle. Since detection, the virus has spread across 17 states, infecting more than 1000 dairy herds, causing concern for the dairy industry regarding the effects on dairy cattle, the risk associated with milk quality and production, and ultimately its risk to humans. It has been shown that pasteurization is sufficient to inactivate HPAIV, if present in milk, making it safe for human consumption. However, unpasteurized raw milk that is routinely consumed and used to make cheese, yogurt, and kefir is a public health concern. We acidified raw milk, a process that is analogous to the preliminary phase of generating fermented milk products, with acetic, propionic, lactic, or citric acid to pH 5; or acidified it with acetic acid to pH 6, 5, or 4. Each sample was subsequently spiked with low pathogenic avian influenza virus (LPAIV) and incubated at room temperature for up to 24 h before being inoculated into 10-day old specific-pathogen-free embryonating chicken eggs. Embryos were assessed daily for viability and hemagglutination assays on the allantoic fluid was used to confirm the presence of viable LPAIV. The reduction of viable virus was significantly correlated with both time and pH but not specific type of acid tested. An acid treatment at pH 4 and 5 progressively reduced viable LPAIV levels over time, with the most pronounced inactivation observed at 24 h. Samples at pH 6 had little reduction in virus viability.
Keywords: Acid; Avian influenza virus; Embryonating chicken eggs; Raw milk; pH.
. 2026 Aug:137:105015.
doi: 10.1016/j.fm.2025.105015. Epub 2025 Dec 26.
The impact of acids, pH, and incubation time on avian influenza virus persistence in raw milk
T L Harrell[SUP] 1 [/SUP], A Shwani[SUP] 2 [/SUP], D L Suarez[SUP] 3 [/SUP]
Affiliations
- PMID: 41722994
- DOI: 10.1016/j.fm.2025.105015
In March 2024, highly pathogenic avian influenza virus (HPAIV) clade 2.3.4.4. b H5N1 was detected in dairy cattle. Since detection, the virus has spread across 17 states, infecting more than 1000 dairy herds, causing concern for the dairy industry regarding the effects on dairy cattle, the risk associated with milk quality and production, and ultimately its risk to humans. It has been shown that pasteurization is sufficient to inactivate HPAIV, if present in milk, making it safe for human consumption. However, unpasteurized raw milk that is routinely consumed and used to make cheese, yogurt, and kefir is a public health concern. We acidified raw milk, a process that is analogous to the preliminary phase of generating fermented milk products, with acetic, propionic, lactic, or citric acid to pH 5; or acidified it with acetic acid to pH 6, 5, or 4. Each sample was subsequently spiked with low pathogenic avian influenza virus (LPAIV) and incubated at room temperature for up to 24 h before being inoculated into 10-day old specific-pathogen-free embryonating chicken eggs. Embryos were assessed daily for viability and hemagglutination assays on the allantoic fluid was used to confirm the presence of viable LPAIV. The reduction of viable virus was significantly correlated with both time and pH but not specific type of acid tested. An acid treatment at pH 4 and 5 progressively reduced viable LPAIV levels over time, with the most pronounced inactivation observed at 24 h. Samples at pH 6 had little reduction in virus viability.
Keywords: Acid; Avian influenza virus; Embryonating chicken eggs; Raw milk; pH.