“Slight Notes of Grass:” A Milk Hauler’s Guide to Grading Milk Odor
“…A rich, buttery softness, with notes of hay and chlorophyll.”
…Not something you’d expect to hear a milk hauler say, perhaps, but actually an integral part of the job!
Like so many jobs in the industry, there’s more to milk hauling than meets the eye. As certified handlers for food safety, bulk milk transporters are responsible for inspecting and evaluating the milk they collect at each farm. Part of that evaluation involves – you guessed it! – checking milk’s odor.
The Process: Take A Deep Breath!
To properly check for off milk odors that might signal an issue with the milk, milk haulers open the bulk milk tank at each farm and take two or three deep whiffs. Normally, milk has virtually no odor (although sometimes it may smell slightly sweet), so any strong scent is immediately reported to the producer, dairy cooperative, and the receiving plant so that the underlying issue can be investigated and resolved.
If Something’s Off…
If a subtle odor is detected, the milk can be heated to 100 degrees for a few minutes and re-checked. Any odors will be intensified by the heat, and should be easier to detect.
Milk with a strong off odor is rejected onsite – not loaded into the milk tank – to prevent it from contaminating the whole load. To determine the cause of the issue, a sample is collected for further testing at the receiving facility.
What Are They Looking (Or Rather, Smelling) For?
Some common off-odors:
- Feed odors: Milk can take on different odors when feeds change. Some forms of animal feed may carry through to impact the animal’s milk, producing (in extreme cases) odors of grass, silage, turnips, and hay. Producers can minimize these by taking animals off-feed for at least four hours prior to milking.
- Barn-like smells: These odors are usually the result of inadequate ventilation or sanitation, leading animals to inhale foul air. Further testing can help establish the cause, so that it can be addressed.
- Garlic or onion odors: Can result if animals consume garlic, onions or leeks.
- Musty or moldy odors: Usually caused by feed or stagnant water consumed by the animal.
- Sourness: Bacterial growth is to blame for this foul odor, which most will recognize immediately. It can be prevented with proper sanitization techniques and milking practices, as well as prompt cooling of the milk tank.
- Weedy odors: Odors such as ragweed, peppergrass, and bitterweed may be detected if an animal has ingested such plants shortly before milking. To prevent them, producers should do everything possible to keep animals away from these kinds of plants – especially around milking time.
- Other unusual odors: scents of sanitizers, paint, oil, kerosene, medicinal substances, or anything else that may render the milk unusable may be caused by contamination (either direct, or from airborne contaminants).
An unusual odor is not always cause for concern, though. Many factors can affect evaluation, so haulers should strive to avoid anything that could impair their ability to accurately test the milk. External factors such as milk house odors, gasoline fumes adhering to clothing, and odors from smoking should be ruled out. Haulers should also avoid ingesting or chewing aromatic candy, gum, medicine, and beverages, and avoid using strongly scented toiletries (such as scented hand sanitizers or lotions) to prevent these from affecting their evaluation.
Though it may not sound glamorous, evaluating milk’s odor is an integral part of assuring its quality and safety. And if you’ve ever taken a larger-than-advisable whiff of sour milk, you’ll definitely appreciate the lengths haulers go to ensuring that the milk we get is farm-fresh every time.