Raw Milk Safety

Safe production of raw milk starts with raising cows in conditions and using practices conducive to maintaining health and preventing disease.

In this respect, the land and diet of the cow, the environment in which she is kept and her contentedness, is as important as the milking process, hygiene in the parlour and the subsequent handling and bottling of the milk.

The organisms that might contaminate raw milk and cause spoilage, or possibly illness, are those found naturally in water or soils or in the mammalian gut where they are usually dormant and perfectly benign. Indeed, some are symbionts needed, in small quantities, for good health. However, in certain conditions they will over proliferate and, if a cow is not in optimal health, they may pass through her and be a potential contamination risk at milking time.

PASTURE HYGIENE

The ideal conditions for the proliferation of undesirable organisms are those created by monocultures, and by the use of artificial fertilisers, herbicides and chemical sprays, spreading slurry on grazing or mowing fields, as well as digestate from bio-digesters. None of these are found in natural ecosystems and all significantly harm and diminish the volume and diversity of healthy soil organisms. The subsequent pollution and soil degradation caused reduces soil pH and creates a toxic environment.

It is this environment that favours the growth of potentially pathogenic organisms. Nature will always attempt to heal and the latest science suggests that these organisms, harmful to susceptible humans, are simply nature’s army set forth to re-balance the soil ecosystem and neutralise the poisons and toxic environment at we have created. If we poison the land, we ultimately poison ourselves.

A healthy, balanced soil ecosystem is the basis of clean, hygienic pastures, not sterile, but teaming with healthy microbes where there is no space created for, nor any need for pathogens to flourish.

RUMEN HYGIENE

Cows grazing these healthy diverse hygienic pastures will, in turn, obtain all the nutrients they need for optimum health and their rumen hygiene will be maintained similarly teaming with healthy microbes. And where, again, there is no space created for, nor any need for pathogens to flourish.

This means that at milking time, whilst we thoroughly wash a cow’s udder, if there were any inadvertent faecal contamination that reached the milk pail, the chances of it containing any pathogenic organisms would be extremely small.

EMOTIONAL HYGIENE

A cow’s emotional health also has a great impact on her physical health, which affects her rumen health and the quality of her milk. Just as with us, stress in cows causes a reduction in immune function and increases susceptibility to disease.

Happy cows kept in natural family groups on healthy pastures will produce milk of the highest quality and lowest risk potential.

MILKING HYGIENE

When it comes to milking, hygiene is paramount. Whether sitting on a stool with just a milk pail or using a machine, aim to milk in an area that is as clean and dust-free as is practical.

Use warm, soapy water and one side of a clean cloth to thoroughly wash the udder, paying particular attention to the teats and teat ends. Wring the cloth out and wipe the udder with the clean side. For those who wish to take extra precautions, or for a cow that is particularly dirty, then pre-wash with a hose and use an anti-microbial like Hibiscrub in the warm water.

Many natural cheese-makers prefer not to wash the udder and teats at all as the microbes on the teats are those that help provide the distinctive flavour of the cheese. Instead, they will use a handful of clean straw or ‘wood wool’, which is fine slivers of soft wood, to just wipe the teats.

Always forestrip a few squirts from each quarter to check the milk quality and remove the residual milk from the teat canal. Take care when attaching the cluster to ensure none of the inflations flop onto the floor or touch any other part of the cow before slotting onto the teats.

It is important to start chilling the milk immediately after milking. This is because raw milk inherently contains many beneficial lactose-fermenting organisms and their activity will naturally sour the milk by turning the lactose, milk sugars, into lactic acid. Rapidly chilling milk attenuates their activity and will keep the milk sweeter for longer.

The most practical way to do this on a small scale is simply to place the stainless-steel milk pail into a bucket of cold water while walking the cow back out to the field and washing the milking machine. Traditionally, before refrigeration, milk would have been kept in a vessel settled into the bed of a nearby brook to keep chilled, and it worked extremely well.

WASHING THE MILKING MACHINE

A milking machine must be washed immediately following milking to prevent any milk from drying inside the tubes. The first wash through should be with warm soapy water using a normal household detergent (washing up liquid). Warm, so that the fats are lifted, but not hot, which would cook the proteins onto the internal surfaces.

Followed by the main wash with a specialist dairy equipment cleaner, either strong acid or alkaline based, for example Agroserve Autoklene, at the temperature recommended, usually over 85C. For those not wishing to use any chemicals, this is one area where an exception really needs to be made. For without the ability to physically rub inside the tubes, biofilms can quickly establish and will contaminate milk.

Finally, everything should be thoroughly rinsed with scalding water to ensure all chemicals are removed and the equipment is left clean and sterilised. Scalding water can be better for sterilisation than the traditional use of hypochlorite. This is because hypochlorite needs to be rinsed off equipment and not all mains water is as clean and sterile as we’d like and may contain Pseudomonas. These cold tolerant spoilage organisms will cause milk to go off more quickly at fridge temperature.

When not in use, milking machines should be kept in a dust, insect, bird and vermin-free place.

BOTTLING HYGIENE

With a couple of changes of cold water, the milk in the pail sitting in the bucket should be cooling nicely whilst the milking machine is being washed.

Back in the kitchen, and with clean hands and a clean apron, pour the milk through a milk strainer with a good quality filter, similar to a coffee filter. This will remove any tiny bits of debris. There should be none, but the inexperienced may inadvertently suck up perhaps the odd cow hair. It also allows a visual inspection of the filter to check there are no clots in the milk.

Bottle the milk into clean, sterilised (using scalding water) bottles and take care when putting on the lid not to touch the inside of the lid. The bottles can then be chilled down to 4C in the fridge. Ice packs can be placed between each bottle to help them chill more rapidly. Aim to get the milk down to 4C within 2 hours from the time of milking. Even better if it can be within 1 hour.

MILK TESTING

Raw milk from a beloved house cow, kept in good conditions and fed an appropriate diet, will almost certainly be safe and of high quality. Always ensure any withdrawal periods are adhered to for cows treated with any medications (double the withdrawal period if following organic principles) and only drink raw milk from cows tested free from bovine tuberculosis.

For those wishing to enjoy the health benefits of raw milk with the additional reassurance that their milking hygiene is good and their risk control processes are working, then sending a milk sample for testing will provide verification.

There are several laboratories around the country that test milk, but the easiest for most will be to contact the National Milk Laboratories. They will send small sample pots which should be filled with fresh, chilled milk and sent by guaranteed overnight post. The milk needs to be kept below 4C on the journey with ice packs in insulative packaging.

The table shows the pathogen tests that might be undertaken periodically, perhaps once per lactation a couple of weeks after calving. Then, more frequently as desired, testing for somatic cell count (SCC) will give an indication of udder health, and total viable count (TVC) of colony forming bacteria and coliforms can be used to verify that milking hygiene is on track. These are considered indicator organisms with TVC reflecting equipment hygiene and coliforms reflecting faecal contamination and, thus, udder preparation effectiveness.

An increase in the indicator organisms, however, does not necessarily mean there are any pathogens present. It indicates primarily that washing hygiene in the parlour or at bottling, or speed of chilling, is lacking and these areas should be reviewed first.

For most house cow keepers though, testing milk is unnecessary. We have lived in harmony with cattle for millennia safely drinking their milk. It was only through the industrial revolution and the bringing of cattle into city centres, kept in filth and fed wholly inappropriate diets, creating the perfect toxic environment for pathogens to flourish, and people themselves in poor health and living in unsanitary conditions, that sickness associated with raw milk became a problem and its reputation tarred.