One of the exciting things about working with Merrimoles Farm on the Nettlebed Estate is the potential inherent in their milk. The herd is a mixture of Friesian Holsteins with Swedish Red and Montbeliard bred into the herd for increased vigour. Increased vigour is the immediate benefit for the farmers along with better health, less likelihood of lameness and better fertility. However it isn’t just a benefit to the farmer. The cheesemaker (that would be me) naturally gets better milk from healthy, happy animals but the breeding with Swedish Red and Montbeliard is exciting because the solids in the milk of both of those breeds lend themselves more to cheesemaking than that of the Friesian Holstein or Holstein itself. In addition to that, the animals graze on organic pasture and, as a result, spend most of the year happily outside, munching grass, flowers and herbs in the fields, which in theory means that they should have a diverse diet which will lend to aromatic compounds in the milk and the potential for a diverse grouping of lactic acid bacteria derived from the bacteria present on the teats.
I had come into the discussions with Rose and with Merrimoles Farm with a mental ticklist of what I was looking for in a milk supplier, namely, interesting breeds (check), outdoor grazing (check), varied pasture (check), preferably organic or as near to as possible (check). Part of this is ideological, I don’t want to be involved in an enterprise where there are unhappy animals and where the farming isn’t sustainable and respectful to the environment. Part is flavour driven. Interesting breeds, varied pasture and organic management of the herd and pasture should, in theory, translate to the most interesting milk. In other words, if I can unlock it, there’s a lot of potential for good flavours in our cheese.
‘Our milk is really good’ Rose told me proudly when we first met.
We collected a sample from the bulk tank to drink it fresh and (naturally) unpasteurised. It tasted lovely. I agreed with her. On other occasions that I have drunk it since then, it consistently tastes lovely with a milky sweetness, mineral undertones and a velvety creamy mouthfeel.
‘And we get really great test results too’ she continued, ‘Dairycrest actually say that our counts are really low. For an organic farm it’s practically unheard of.’
When I first visited the farm, Phil, the farm manager showed me a printout of their milk results which included fats and protein content as well as their routine total bacteria counts. Having looked over other milk results in the past when I was Quality Assurance Manager at Neal’s Yard Dairy, I too was surprised at how low some of the counts were. I expressed my surprise to Phil also who confirmed that yes, they were often told how rare it was for an organic farm to hit those levels. It was something they were all proud of and justifiably so. For their current customers this is exactly what they need and want.
I was a little more cautious. Low total counts, seemed to me a good starting point, but more important than that is what that total count breaks down into. Ideally, of course, that total count is entirely composed of lactic acid bacteria. Worst case scenario, it’s entirely composed of Listeria monocytogenes or another pathogen. As we drove away from the farm, I mentioned to Rose that, before we got into cheesemaking, we needed to build up a history of testing the milk in more detail.
‘For raw milk cheese,’ I explained, careful not to cast aspersions on what was evidently, very carefully produced milk, ‘It’s not so much the total counts we’re concerned about, but what’s in there. So we need to send off some samples for testing and cover all the pathogens: Listeria monocytogenes, Staph. aureus, E.coli O157 and Salmonellae.’
It wasn’t urgent to get started testing straight away and actually we are hardly going to go and find another milk supplier. Our cheese business is being started to make better use of the Merrimoles milk. Whatever the results, we were already committed to working with them, so to begin testing nearer our production time made more sense. I took a bottle of milk away to do a lactofermentation at home. They took 48 hours to set, tasted yoghurt-like, although a little bitter, and had about one gas bubble. I would have been happier to find no gas bubbles and to not have tasted the slight bitterness, but I wasn’t too bothered at this stage.
When we did begin our testing in May this year, however, we had a bit of a shock. The total counts were low, as usual, but the lactic acid bacteria counts as a proportion of that were also a lot lower than we had hoped for. We thought, especially as we want to culture our own starters, that we would be aiming for 80% of the total count to be lactic bacteria. We were finding considerably less than that.
This means for our cheesemaking, culturing our own starters is a project for a few years time and won’t be happening initially. If you make your own starters, the argument goes, you will have a more diverse population of bacteria but, of course, you don’t know what you are getting and they are likely not to acidify as strongly as bought and proven starters. Just at the moment, we need to use plenty of proven starter to get our milk to acidify. This is fine, I can work with that and still do my best to use a varied and interesting cocktail of cultures. What makes me a little nervous though is that not having a naturally strong population of lactic acid bacteria does mean that we don’t have a built in safety mechanism in form of the milk’s natural ability to out compete pathogens. If something nasty gets in, it can have a little pathogen party, reproducing itself all over the shop.
‘What does this mean for your cheese?’, I hear you ask.
Well as I said, we’ll use bought in starters and in addition we will record our acidity curves with every make. We will also prepare ourselves for higher testing costs as we will have to test each batch that doesn’t acidify quickly enough and higher wastage for the cheeses whose test results don’t make the grade. In the longer term, we’ll begin learning a lot about the factors that encourage or discourage lactic acid bacteria, because, in theory, with organic production and grazing outdoors, we should have plenty of them and yet we don’t. With that in mind, at Slow Food’s Cheese this year, I listened avidly to their workshops on milk production. But that is a blog-post for another day.
More importantly, all of a sudden, all the arguments in defense of raw milk that I have trotted out obediently, on behalf of Neal’s Yard Dairy to officials and other quality assurance managers, clarified in a moment of epiphany.
If you don’t want to bottle milk and offer your customers long shelf life of what is naturally a short shelf life product, pasteurisation is irrelevant.
It doesn’t make sense for a cheesemaker to seek out milk with low counts or be encouraged to use pasteurised milk which it is perceived as being safer than raw milk.
If the raw milk has a healthy population of natural bacteria, it’s the safer choice.
A lot of what a laboratory scientist may consider to be a risk and that has been worked into HACCP and the food safety risk analysis we all do, suddenly seems misdirected and possibly dangerously so. Pasteurising doesn’t sterilise. It doesn’t make milk a perfectly clean slate, there are still some organisms in there or organisms can get in there even if you think you’re doing everything at the very pinnacle of hygiene. With low counts, it’s key to your cheese quality that your starters work quickly. If they are slow to start, then they can be out competed and potentially they don’t get the upper hand. This doesn’t neccessarily happen – you might be lucky but it’s like driving without your seat belt. It isn’t a given that you’ll have an accident but if you do the consequences are worse.
I now see very clearly, that it’s not a question of absolutes and black and whites. It’s not that low counts of staph aureus or enteros are automatically good. It really depends on what they compete against. Cheesemaking is a question of managing populations and communities of organisms. It’s so much more complicated, nuanced and subtle than low counts good, high counts bad and it’s not a question of limits and levels but of balances. This is as necessary for food safety every bit as much as to get the recipe to work.
I thought I understood this when I worked at Neal’s Yard Dairy. I was only half way there.
Now, I really get it.