How to Make Sure You Grow Only Desired Bacteria in Your Cheese

I’ve talked about a lot in the articles on the website about the importance of making cheese in sanitary conditions.

It’s probably something we’re all aware of, but when was the last time you thought about why it is so vital?

Sanitisation is beyond simple cleaning. We should clean all of our cheese making equipment every time we use it (including our hands), but, to my mind, this means warm soapy water used to remove cheese or curd residues and the fats left clinging to the mould when it’s been used. However, once your equipment has been dried after cleaning, it will not be sanitised.

We don’t like to think about it, but every surface in our homes is teeming with bacteria, especially the cloth you use for cleaning the work surfaces; they like the moistness of it and breed like wild fire on the supply of nutrients they can find in there!

Unfortunately, those bacteria are so hardy that whilst a simple warm and soapy wash might get your equipment clean enough to put back in the cupboard after use, it is not enough to ensure safety when making your next batch of homemade cheese.

This article will examine the best ways of getting your working environment and equipment sanitary and safe for making cheese at home.​

The Irony of Sanitisation

There is a certain irony about sanitisation in cheese making, we focus a lot of effort in killing bacteria on and in our equipment before making cheese, but then add bacteria to our milk right at the start of our cheese making process.

Of course, the distinction is that one (and only one) of those bacteria are desirable, whilst the others are most definitely not (one study found over 7,000 different kinds in one home).

In the article all about milk, I talk about what a fantastic environment milk is for breeding bacteria. It is full of nutrients they can feed off and, when we’re using it to make cheese at home, we raise it to just the right temperature for the them to breed rapidly.

The truth is that some of those bacteria (and other micro organisms, such as yeasts and moulds) are really, really bad boys. There can be quite a heady selection in your kitchen, including:

  • Campylobacter (diarrhoea, cramping, fever, life-threatening infection)
  • Clostridium botulinum (double vision, slurred speech, difficulty swallowing, untreated can cause paralysis and death), Cryptosporidium (stomach cramps, fever, vomiting)
  • E. Coli (severe diarrhoea, vomiting)
  • Listeria (fever, headache, convulsions, can cause death)
  • Salmonella (diarrhoea, fever and stomach cramps, can cause death).

If you would like more information and the full, scary illness details of the damage these bugs can reap, they can be found in this chart.

These bacteria cause millions of infections every year in the developed world, and I would love it if none of us were to join that statistic by having impeccable hygiene standards in our kitchens.


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Control of your Environment

The first step to keeping equipment sanitary is to avoid equipment ‘mix & match’, i.e. use the same tool for the same task each time.

Identify a spoon that you always and only use for stirring milk and curds and don’t use it in tonight's soup or stew. Use the same tub for collecting curds and the same pan for warming your milk and creating your cheese. Avoid using the one you made spaghetti Bolognese last week.

The benefits of this approach are two-fold.

  1. You remove the risk of cross contamination, i.e. taking the micro-organisms that exist in one environment and introducing them to your cheese making world.
  2. It helps keep your cheese making equipment distinct from generic kitchen equipment, which makes it much easier to keep on top of the thorough cleansing regimen you should be following.

How to Sanitise Cheese Making Equipment

There are some very simple routines to make sure your cleaned equipment has been sanitised and rendered germ-free before cheese making with it.

The two best ways of killing bacteria are through the application of certain bleach-like chemicals (do NOT use household bleach to sanitise your equipment), or through high heat, usually delivered by boiling equipment.

Chemically Sanitising your Cheese Making Equipment

Stainless steel equipment, such as pans and colanders as well as any food grade plastic material, like cheese presses and moulds, can and should be treated chemically.

I use a dedicated sterilising agent, more commonly associated with home brew activity. I have faith in it because it is formulated specifically to sterilise materials used for making food products. It’s very easy and safe to use and there are no unpleasant bleach smells.

To use it, follow the instructions on the pack. I have a little paranoia on the sanitising front and so always rinse out four times afterwards, just to make sure that any risk of flavour transfer is eliminated.

Cheese Making Equipment Which Should be Boiled

Any cheesecloth I use, I sanitise using boiling water. This is because it is very hard to rinse a chemical cleaner out of the fibres, and the risk is that this will leave an unpleasant taste in the material that transfers to your cheese.

It is also possible to sterilise equipment through the heat generated in an oven or dishwasher (on a hot setting). Although these seem sensible enough routes, I have never used them as my personal preference for using sterilising powder is too strong to ignore.

Always sterilise your cheese making equipment immediately before using it, so that micro-organisms have no time to repopulate after cleaning. And make sure to remember that both your skin and kitchen worktop are overwhelmed with bacteria, so handle sterilised equipment only with very clean hands (I use Mrs. Meyer's Hand Soap Lemon Verbena, 12.5 Fluid Ounce (Pack of 3)) and use paper kitchen towel or fresh, clean tea towels to stand your equipment on once it is cleaned.With clean equipment, you stand a lot better chance of only cultivating the bacteria you need to make great cheese.

The Right Equipment for Cleaning and Sanitising

These are the products I use for sterilising - hover your mouse over for the latest Amazon price in your location.

A sturdy scrubbing brush that's easy to hold is essential. This will get the curd residues off your equipment.

These mini brushes are perfect for getting the holes in your cheese moulds nice and clean.

This sanitising powder is the final stage after scrubbing your equipment. It will leave all of your cheese making tools sanitised for the next batch.