Chickensplash! Exploring the health concerns of washing raw chicken

Authors: CARMODY, CAITLIN - Montana State University; Mueller, Rebecca; GRODNER, BENJAMIN - Montana State University; CHLUMSKY, ONDREJ - University Of Chemistry And Technology; WILKING, JAMES - Montana State University; MCCALLA, SCOTT - Montana State University

Submitted to: Physics of Fluids
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/4/2022
Publication Date: 3/24/2022
Citation: Carmody, C., Mueller, R.C., Grodner, B.M., Chlumsky, O., Wilking, J., McCalla, S. 2022. Chickensplash! Exploring the health concerns of washing raw chicken. Physics of Fluids. 34(3). Article 031910. https://doi.org/10.1063/5.0083979.
DOI: https://doi.org/10.1063/5.0083979

Interpretive Summary: Kitchen hygiene during food preparation, particularly when handling raw meat products, is critical to limiting the spread of food-borne illnesses. Here, we examined how washing of raw chicken can spread bacteria that have colonized the surface to other locations by quantifying different splashing parameters, including height, flow type and surface material (with and without skin). We linked these physical parameters with culture and culture-independent methods with sequencing of the 16S rRNA phylogenetic marker to quantify the microbiome present on the surface of the chicken. We found that faucet height was the largest factor in spreading bacteria in droplets, and the presence or absence of skin played the largest role in differences among the members of the microbial community. Although 16S rRNA sequencing cannot distinguish between pathogenic and non-pathogenic members within a genus, culturing identified numerous genera with pathogenic members. Thus, washing chicken has the potential to spread harmful bacteria widely when they are present on the surface of raw chicken.

Technical Abstract: The Food and Drug Administration (FDA) recommends against washing raw chicken due to the risk of transferring dangerous pathogens through splashed drops of water. Many cooks continue to wash raw chicken despite this warning, however, and there is a lack of scientific research assessing the extent of microbial transmission in splashed drops. Here we use large agar plates to confirm that bacteria can be transferred from the surface of raw chicken through splashing. We also identify and create phylogenetic trees of the bacteria present on the chicken initially compared to the bacteria transferred during splashing. While no pathogens were identified, we note that organisms in the same family as pathogens were transferred from the chicken surface through splashing. Additionally, we also show that faucet height, flow type, and surface material play a role in splash height and distance. Using high-speed imaging to explore splashing causes, we find that increasing faucet height leads to flow instability that can increase splashing. Further, splashing from soft materials such as chicken can create a divot in the surface, leading to splashing under flow conditions that would not splash on hard surfaces. Thus, we conclude that washing raw chicken does risk pathogen transfer through splashing, and that changing washing conditions can increase or decrease the risk of splashing. Further research could be conducted to recommend safer washing practices for cooks who prefer to do so. Additionally, we hope to open the door for additional research on flow streams and splashing from soft materials.