One example of how these techniques can be applied has been the identification of certain bacteria that can make refrigerated, pasteurized milk in partially filled containers turn gray or be streaked with gray, as discussed in a July 2017 article in the Journal of Dairy Science. “We found that there are organisms that required oxygen to make the color compound, and we were able to identify which genes are responsible. So if you have these genes and they are expressed and they have enough oxygen, then you are going to get this defect. It was a microbial contaminant that causes the problem, not a disgruntled employee tampering with the product, as had been suspected,” Dr. Wiedmann says.
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Other applications include individualized troubleshooting to identify the likely cause of a defect, such as a taste defect, so that intervention can begin to eliminate that cause. Using the tools for genomic sequencing, it is now possible to quickly take a bacterial isolate and accurately identify the microbes involved. “We want to get to the point where individual dairy processors can do this type of testing. As futuristic as it may sound, I think it is feasible that it will probably happen in three to five years in more sophisticated plants,” Dr. Wiedmann notes. Metagenomics testing is likely to supplement traditional dairy testing methods, not replace them, and will allow for more risk-based testing, he says.
U.S. dairy products are “probably some of the safest products around, and the countries where we export pay premium for U.S. dairy products because of the excellent safety record,” Dr. Wiedmann elaborates. “Anything we can do to show that we use cutting-edge tools will hopefully improve that ability for the U.S. to export some of these products.”
A team of researchers at Osaka University and Rakuno Gakuen University, both in Japan, have developed a technique that uses a camera and AI to monitor lameness among dairy cows. Lameness, if untreated, can result in declining quantity and quality of dairy production. The researchers waterproofed and dustproofed a camera-based sensor capable of measuring distance to an object and set it in a cowshed. Based on the large number of cow gait images taken by the sensor, the researchers could characterize cow gaits and detect cows with lameness through machine learning.
Professor Yagi Yasushi at Osaka University says this research “will mark the start of techniques for monitoring cows using AI-powered image analysis. By showing farmers cow conditions in detail through automatic analysis of cow conditions, we can realize a new era of dairy farming in which farms can focus entirely on health management of their cows and delivering high-quality dairy products.”
Raw, Unpasteurized Milk
One dairy product that continues to be associated with disease outbreaks is raw, unpasteurized milk and cheese. The FDA does not regulate the intrastate sale or distribution of raw milk, leaving that up to each state. Thirty-one states allow consumers to purchase raw milk directly, although in many states it can only be purchased at the farm, at farmers’ markets, or through a cow-share program. Twelve states allow its purchase at retail stores. Raw milk cannot be sold across state lines or internationally. In Canada, it is illegal to sell or buy raw milk.
Research published in 2017 of the CDC’s Emerging Infectious Diseases reported that unpasteurized dairy products are responsible for almost all of the 761 illnesses and 22 hospitalizations in the U.S. that occur each year because of dairy-related outbreaks attributed to Shiga toxin-producing Escherichia coli, Salmonella spp., Listeria monocytogenes, and Campylobacter spp. People who consume raw milk are 838.8 times more likely to experience an illness and 45.1 times more likely to be hospitalized than people who consume pasteurized dairy products. The cause of most of these outbreaks is pathogen contamination at the dairy farm, according to the report.