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The effect of following organic or conventional dairy farming practices on the raw milk microbiome.

D. Van De Grift



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The effect of following organic or conventional dairy farming practices on the raw milk microbiome.
D. Van De Grift*, G. Angima, L. Goddik, J. Cruickshank, S. Park. Oregon State University Corvallis, OR.

Fluid milk consumption has seen a decrease in consumer demand over the last 10 years, while dairy commodities (i.e., cheese) has been increasing. Along with consumers' demands, organically produced dairy products are gaining in popularity than conventionally produced products. These consumer trends demand that a high standard of raw milk quality be met by farmers. The aim of this study was to assess how following organic or conventional farming practices affect the microbiome of raw milk. Four organic and 4 conventional farms having between 100 to 260 and 300 to 450 milking cows respectively were selected from, and located within Oregon's Linn and Marion counties. Bulk tank (BT) milk samples were collected along with environmental samples, 3 different visit per quarter (sampling period). Each sampling period is the first month of each quarter (January, April, July, and October). Sampling the environment of the farms at the same time as the BT sample, furthers the understanding of how environmental microorganisms can influence the raw milk supply. The environmental samples were collected from feed, current bedding, fresh bedding, and a swab of a towel used in the milking parlor. Aerobic and coliform plates were performed immediately on milk samples upon arrival to the lab, and 16S rRNA sequencing based on V4 region in raw milk and environmental samples was performed once all samples were collected for each quarter. The 1st quarter data suggest that when both organic and conventional herds are contained in a barn that there is more coliform and anerobic bacteria in conventional milk than in organic BT samples (P < 0.05). There is no difference between BT bacterial counts and bedding material type from either organic or conventional farms (P > 0.05). Using 16S rRNA sequencing in addition to the bacterial plating has provided a detailed description of the bacterial differences on each farming site, within farming groups, and between farming types.

Keywords: milk, microbiome, high-throughput sequencing.

Biography: My name is Daria Van De Grift, and I am a masters student at Oregon State University in the Food Science and Technology Department. I am studying how following organic or conventional dairy farming practices effects the raw milk microbiome. I received my bachelors from Oregon State University in 2017, where I proceeded to work in the dairy industry for two year before returning for my masters. My favorite part about my thesis is getting hang out with all of the dairy cows when I visit the farms.