Do Aged Cheeses Contain Probiotics?

Probiotics. The new darling of health and advertising. Do cheeses really contain any of these amazing, essential microbes?

Aged wheels of raw milk cheese - Elk Mtn by Pholia Farm

Aged wheels of raw milk cheese – Elk Mtn by Pholia Farm

While I have no letters after my name (unless I capriciously add them), it doesn’t require a university degree to understand that bacteria, both beneficial and hurtful, can only live under certain contidions. I am a cheesemaker and I study science as it relates to dairy. I know what cultures I add to milk to make cheese. Very few of these are currently considered probiotic. And even if they were, when cheese is aged, the bacteria gradually die off as they run out of food to metabolize. So even when probiotic cultures are used, they do not survive longterm aging*. In fact, I was at a conference in England this last summer where research into genetically modifying probiotic bacteria to survive cheesemaking and aging was discussed. (Without much enthusiasm on the part of the artisan cheesemakers present, I might add!)

* I did find that some aged cheeses are commercially being designed to include probiotic bacteria that survive long term aging. These cheeses are labeled as containing probiotics and are not available widely as of yet. I think you can expect to see more products such as this in the future- if nothing else, they will be introduced for the market value they will bring.

I was doing some research today for my latest book (on raw milk production and consumption). I was reading a on probiotics that I chose for it’s high ranking and great reviews on Amazon.  After perusing the front chapters, I skipped to the section containing information about cheese and dairy products – and immediately had to begin putting yellow highlighter frowny faces in the margins (my system for reviewing books). At first I wondered if perhaps my information was wrong, but then found another contradiction that basically confirmed that the author was not really aware of at least this portion of his subject. (I sure hate it when what you think is going to be a reputable source, turns out to be suspect.)

So lets go over a few basic things that you can always apply to probiotics -to help determine for yourself if a food is a good source of these helpful bacteria.

  1. In order to be probiotic, the bacteria must survive the harsh environment of our stomach and travel on to the next portions of our digestive system. Not very many bacteria have this capability – the stomach is one of the first defenses against bacterial contamination of food!
  2. Probiotic bacteria  in food must have a source of nourishment – or they will die (unless, of course, they are held in stasis through something such as freezing). This is true of all bacteria. Once a food is fully fermented, the bacteria begin to perish unless fermentation is suspended – through refrigeration or some other means. Even then, their life span is limited.
  3. High heat, such as scalding or boiling, kills all but bacteria that are capable of forming spores that protect them from the heat.  So even if milk or cheese or whey contains probiotic bacteria if it is cooked they will die.

The bacteria currently considered probiotic include only a couple of strains regularly used in making cheese. A fresh cheese that uses these bacteria as a part of its fermentation process will likely have some of these helpful microbes still living, but the longer a cheese is aged, the fewer bacteria remain alive. Aged hard cheeses are not sterile, but the life forms found on and around them are typically environmental, not those that were added during the cheesemaking process. In cheeses made using high heat and added acid, such as whey and milk ricotta, any probiotic bacteria in the whey will be killed during the high heat treatment (along with enzymes and milk’s natural defensive systems).

Bottom line, don’t look to aged cheeses as a probiotic source, yogurt is a no-brainer if probiotics are your goal! Instead, enjoy aged, natural cheeses for what they are meant to be – deliciously preserved (usually through fermentation) milk.

P.S.: So where can you find information on probiotics that you can trust? Hard to say! Popular topics are a magnet for publishers and writers. The best advice is to consult more than one source, preferably those that list scientific studies as their sources – but of course all the studies that will be helpful have not been done, nor is science a static subject.

Oh, here are a couple of sources I used to write this post:

Vet. Med. – Czech, 47, 2002 (6): 169–180 Review Article 169 – Lactic Acid Bacteria, Probiotics and the Immune System
R. HERICH, M. LEVKUT
Department of Pathology, University of Veterinary Medicine, Košice, Slovak Republic

J Dairy Sci. 1987 Jan;70(1):1-12.
Survival of lactic acid bacteria in the human stomach and adhesion to intestinal cells.
Conway PL, Gorbach SL, Goldin BR.

http://www.dairycouncilofca.org/pdfs/probiotics.pdf, “Friendly Bacteria with a Host of Benefits”

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC106298/  Probiotic Cheese

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Chasing Coliform Counts

I was recently visiting England to attend “The Science of Artisan Cheesemaking” conference and had the great additional luck to visit an amazing farmstead creamery- Hill Dairy in Somerset. Not only was the facility quite possibly one of the most well thought out and constructed small creameries that I have ever visited, but owners Will and Caroline Atkinson, were as charming and lovely as their picturesque English farm. Since I got back to the US, we have been corresponding about a problem that Hill Dairy was experiencing both during my visit and on and off for a good part of this fall. A problem, unfortunately, that caused the loss of many batches of cheese milk and is a problem that plagues many farmstead cheesemakers (sometimes even without their knowing). High coliform counts.

3M coliform petri film with count at about 400cfu/ml (black dots from Sharpie marker on a few) look for a red dot surrounded by or up against an tiny air bubble. each dot with air bubble is one cfu.

First a bit about the large bacterial family called coliforms. These microbes live in the environment of the farm, especially bedding, feed, and soil. But some of them also live in the lower intestine (not only of cows and goats, but of people too) the most well-known being Escherichia coli, better known by its abbreviated name “E. coli”. The presence of E. coli in milk or cheese can be translated as the presence of feces, that’s right, poo. While E. coli and poo in milk are not desirable in any circles, it doesn’t necessarily mean that the milk is unsafe. It is the ne’re-do-well coliform cousin E. coli 0157:H7 that can wreak horrible damage when ingested. (There is another variant that surfaced recently in Germany that is just as nasty and there will no doubt be more variations in the future that will cause horrific food borne illnesses, sickness, and death). So while coliforms do not necessarily mean the presence of pathogens (illness causing microbes) their numbers are a good gauge of milk cleanliness. The higher the general coliform count, the higher your odds that some might be bad.

Currently most data say that high quality raw milk should have fewer than 10 cfu’s (that’s colony forming units) per milliliter of milk.  Some states allow for higher counts and the “fewer than 10”number is somewhat arbitrary, but let’s pretend for now that it’s a great standard. Here at our farm our petri-film plate counts (done on every cheese batch – see my previous posts if you want to know how to do these) show our total coliforms at usually 3-5 cfu’s per ml. Awesome, right? Well, when I got back from England our counts shot up to over 400cfu/ml.  Fortunately for both us and Hill Dairy, tests showed that none of the coliforms were from fecal sources, no E. coliforms. (You can buy petri film plates that will grow E. coli’s in a different color than regular coliforms). Interestingly, but not surprisingly, our APC (which counts total bacteria numbers) didn’t look that bad – until you looked closely and could see that there were tiny air bubbles all over the plate (from the gas produced by the coliforms) and these bubbles had lifted the film from the plate – making it look as though there were not that many colonies growing.

Aerobic plate count showing red dots of bacteria colonies (cfu’s) and lots and lots of tiny air bubbles from coliforms making the plate “uncountable”.

So what do high numbers of “harmless” coliforms do to milk and cheese? Well, these guys eat lactose – that’s milk sugar, (as do starter cultures) and produce both lactic acid and carbon dioxide – that’s gas. The problem with them is that they grow very fast and can often out-compete the added starter culture during a slow fermentation, just like what is done to make most fresh cheeses and lactic set bloomy rinds (like the Atkinson’s were making – and yes it is legal to make them with raw milk in the UK). At Pholia Farm, we make long-aged, low moisture cheese that use a faster acid development and rennet, so we would not have known about our high coliform counts if we were not doing routine lab tests on every batch. While these coliform types are unlikely to make our cheese unsafe, it tells us that something is far from ideal with our process – something that could lead to unsafe food. We don’t only make cheese, we drink our raw milk – we care that it is of the best quality possible for many reasons.

Okay, so both our farm and Hill Dairy had much higher than normal counts, what did it mean and what did we do about it to resolve the problem? The most common causes of high coliforms are dirty teats, poor milking technique, and dirty equipment. While this may seem like an easy fix, when your counts suddenly go from great to horrendous, it can be very confusing.  So let’s go over a step by step procedure for trouble shooting coliform counts – with as little financial investment as possible!

  1. Observe that animals are coming into the parlor relatively free of manure and debris – dairy clipping udders can help.
  2. Verify that established teat and udder cleaning methods are being performed properly and that udder cleaning solutions and sanitizers are effective.
  3. Verify that milking equipment with parts that need replacing, especially rubber parts, are up to date for recommended replacement times.
  4. Verify that cleaning steps for equipment are effective – this includes chemical strength and effectiveness for your water type, temperatures, time, air slug velocity, etc. Swabs can be taken at various points in system and cultured for total bacteria counts to verify effectiveness.
  5. Perform “hyper-cleaning” following guidelines from chemical manufacturer or other dairy representative. This often includes a double strength, double time cleaning and manual cleaning to verify the removal of bio-films and residue that might have occurred from less than ideal parlor practices.
  6. Verify milk chilling process, if used (even with proper chilling, high enough coliform counts will be a problem in lactic technology cheeses)

Don’t be surprised if trouble shooting takes place over many days before you completely conquer the problem. All it takes is one step to be missed, and the problem reasserts itself. For example, our problem seems to have come from our neglect (later in the season) of dairy clipping our ladies udders, combined with wet weather, combined with me forgetting to replace a couple of rubber parts inside of the milking claws , combined with a bit too casual milking and udder cleaning techniques. I would fix one problem, but not all problems at one time. Everything needed to be zeroed out, you might say, before our counts went completely back to our normal low.  It took several weeks of implementing new techniques and replacing parts and hyper-cleaning to shape things back up. During that time the count dropped from the 400, to 100 plus, then to the high 30’s, and finally to under 10.

Coliform petri film showing 3 cfu’s (circled with black ink). This is great!

If you experience a similar extended issue, here are some things you can do so that you don’t lose product, and future income, while you whip things back into shape:

  1. Pasteurize the milk.
  2. Thermize, aka heat shock, the milk (lower temperature than pasteurization, not recognized in the US, so cheeses made from thermized milk are not considered pasteurized)
  3. Switch from lactic cheeses (such as surface ripened and fresh soft) to an aged, quickly cultured and rennet style cheese. (Verify that no E. coli is present)
  4. Switch from freeze-dried direct set culture to bulk starter or mother culture that will provide a faster growing starter bacteria population. (if coliform counts are too high, though, this may not be enough)

Remember that if you are not testing each batch of cheese milk and are making a rennet coagulated, quickly acidified cheese, you may never know that your milk is less clean than it could be! If you do experience a problem, don’t feel alone and remember that keeping sanitation standards high on the small farm, or any farm for that matter, is an ongoing, major challenge. It is a great reminder of how quickly things can change – for the worst.

Fresh Ricotta Balls with Roasted Grapes

I thought I would never get into posting recipes, but I had a lot of fun customizing this recipe for an upcoming class, so hey, why not share with you all? I got the inspiration for this recipe online, but it was pretty bland, so I took it up a notch. I also didn’t have some of the original ingredients, so made some changes. (this all fits in with my cooking style which I call “The Reckless Chef”) Here you go:

First, make the Ricotta

  • 1 gallon milk, any kind, store, farm whatever!
  • Acid- 2/3 lemon juice OR a few tablespoons vinegar (don’t be too crazy and use balsamic) OR two tsp citric acid dissolved in 1/2 cup water.

Pour the milk in a stainless pot and put on the burner. Stir constantly and heat to 180-185. Turn off the heat and drizzle in the acid, stir gently while adding and watch the curd form. Keep adding acid until the watery portion (the whey) is clearish- yellowy-green. Stop stirring and let sit for 10 minutes or so (emphasis on “or so”).  Line a colander with cheesecloth or a thin tea towel. (What the heck is a tea towel, you might ask. A thin, loosely woven towel designed to dry fine china dishes and cover the teapot while it steeps). The curd should be floating on top of the whey now, so take a ladle (perforated is best) and scoop the curds into the cloth. Let them drain and cool until the texture is kind of dry, but moist- try forming balls and if you can still squeeze out a bit of liquid, it is ready. Usually this takes about 20-30 minutes. Mix in about 1/4 tsp salt. Then roll the cheese into balls about 1 inch in diameter. Put in a dish and chill in the fridge for about an hour.

Next Roast the Grapes

  • Red (or whatever) seedless grapes
  • A sprinkle of raw sugar

Heat your oven to 450F. Pull grapes from stems and put in a shallow pan.  Sprinkle with sugar and pop in the oven. Let them roast for about 8 minutes and stir. Then continue roasting until they just start to pop. Stir one more time. When done, take the pan out and let them  cool a bit.

The Rest of the Stuff

  • Nuts- almonds, filberts, or whatever
  • Cookie or something like graham crackers, vanilla wafers, gluten free gingersnaps, whatever
  • finely ground cayenne pepper
  • cinnamon and/or nutmeg

Toast your nuts (I know) then combine all of these ingredients in a food processor (or a ziplock bag and then whack it with your rolling pin) and process until fine.

Serve the Yummy Balls!

Take the chilled balls and roll them in the pulverized nut mixture. Place a couple on a plate (watch your presentation…) then put a large spoonful of grapes around the balls. Then drizzle the whole thing with maple syrup- not maple FLAVORED syrup. And serve. If you are one of those people who are into garnishes, put something green on the plate, like a mint sprig or, you guessed it, whatever.

 

Using 3M Quick Swabs to Build a Food Safety Program for the Farmstead Creamery

Environmental testing of food contact surfaces and other surfaces that workers might easily touch and then cross contaminate a product can help you quickly find gaps in your food safety program. If you read an earlier post I did on the subject, then you may remember that here at our tiny farmstead creamery, we do an APC on the milk used for each batch of cheese. This spring we made some changes in our general procedures that lead to increased bacteria counts in our milk. By using swab testing, we were able to pinpoint where the problem was originating- before the bacteria levels became too high.

We had made several changes on the dairy farm side of processing. First, we greatly shortened the time in which the milk goes from the body temperature of the animal to refrigeration temperatures. Second, we changed some of the cleaning products to more environmentally friendly variations. When I say “environmentally friendly” in this case I mean products that break down quickly into less harsh compound or elements and are therefore easier on a septic system- ours is an oversized domestic system that handles the waste water from our home, dairy, and creamery. Due to the heavy use of cleaning and sanitizing products, our septic tank was functioning at less than optimum and costing us quite a bit in maintenance.

Since rapid chilling of milk is one of the best ways to limit bacterial growth, our problem of rising bacteria counts meant that either the equipment was not being cleaned adequately, or that bacteria was being introduced- in large numbers- at another step in the process. I mentioned we are a very small farm, so it was quite easy to gather the entire team (myself, our daughter, and one intern) and go over the possibilities. After I completed a milking and what I felt was a thorough cleaning and sanitization of the equipment, I swabbed the inside of one of the sections that collects milk from the animal (called a “claw”).  After plating and incubating the results showed many cfu’s, there should have been almost zero. (See the photo later)

Swab Testing: What You’ll Need

  1. Incubator- We use the small, inexpensive version sold by Nelson Jameson (about 90.00)
  2. 3M Petrifilm plates- Aerobic Plate Count and Coliform Count (70-80 cents each)
  3. Plate spreader (comes with Petrifilm plates)
  4. 3M Quick Swabs (about 1.40 each)
  5. Sharpie or other marker

Once you have gathered your supplies, you can begin taking samples. It is a good idea to test far more surfaces in the beginning of a testing program than you may need to do on follow up tests – this will help establish a baseline of awareness. Once enough tests confirm that cleaning protocols (SSOP’s – sanitization standard operating procedures) are effective, you may be able to decrease the number of surfaces tested as well as the frequency.

Steps for Successful Swab Testing

  1. Using a sharpie or marker, write the source of the sample and date taken on the Quick Swab container.
  2. When you are ready to swab the surface, bend the neck of the liquid filled end of the Quick Swab so that the nutrient broth contained in the bulb flows into the end that contains the swab. Squeeze the bulb so that all of the solution is drained.
  3. Twist apart and remove the swab from the tube. Hold the tube so that the broth solution remains inside once the swab is removed.
  4. Rub the end of the swab, holding it at a slight angle so that the sides make some contact with the surface, on the desired area to be sampled. Rub the swab three times over an area of roughly 3-4 square inches.
  5. Return the swab to the broth and close the tube.
  6. Shake the tube for about 10 seconds to mix the sample into the broth.
  7. Remove the swab from the tube, squeezing it inside the neck of the tube to remove as much of the solution from the absorbent material as possible.
  8. Peel back the film on the sample plate (APC or other) and carefully pour the solution onto the center of the plate. It tends to run out very quickly and is tricky to do properly (as you might notice from the photo of the “claw” sample later in this article).
  9. Use the plate spreader to gently press the sample into the plate. Use the flat side for coliform plates and the recessed side for APC plates.
  10. Allow the plate to sit for about 1 minute so that the liquid sample will gel with the plate.
  11. Incubate as directed for the type of sample being run. (For APC it is 90F for 48 hours, for coliform plates incubate at 90F for 12 hours).

Coliform Plates- How are they Different, When and How to Use

When you open a pack of coliform count Petrifilm plates you will immediately notice two things that are different from the APC plates. First, they are red instead of white. Next, the plate is thicker and has a circular “well” that helps contain the sample of fluid, while the APC plates are flat. When you use the plastic plate spreader on a fluid sample on the APC plates, you use the side of the spreader that has a recessed area. When spreading a sample on a coliform plate, use the flat side of the spreader. Coliform plates are a little bit more expensive then the APC plates, at about 75-80 cents each. Coliform plates that differentiate between total coliforms and e. coli are even more costly at about 1.50 each. You can also purchase “rapid” count plates that will give you results in just a few hours.

So why should you choose to run a coliform sample over an APC sample? In general it is best to focus on coliforms when testing surfaces, especially those that might come in contact with raw or finished product. While other bacteria will always be present in a cheesemaking facility, coliforms are from fecal sources and should not be expected or tolerated on surfaces inside the processing area. If a total coliform count reveals no coliforms, then purchasing and using the more expensive e.coli specific plates is not strictly needed. (These policies should be determined by each facility in consultation with a food safety specialist, however. This article is based solely on our experiences here at our own farm)

A coliform plate is read differently than an APC plate. When you look at the incubated Petrifilm coliform plate, you may see multiple small, red dots, just like you do on the APC plate (although they are more difficult to see thanks to the red background color of the plate – which is intentional). Coliform cfu’s will also have a red dot, but it will be surrounded by a little ring of air – a gas pocket produced by the bacteria. Unfortunately (or fortunately depending on how you look at it) the samples I took for this article did not grow any coliforms. Perhaps I should have swabbed the milking parlor floor drain, which would no doubt have created quite a high count plate for you to see!

Lessons in Swabbing

Here at Pholia Farm, swab testing has helped us determine the frequency of cleaning door handles, light switches, and other hand contact surfaces as well as the efficiency of our cleaning protocols for the cheese vat, milk cans, and milking equipment. Thanks to this quick and easy test we were able to pinpoint the gap in our process – in this case inadequate cleaning products – and make immediate changes. In our case, we returned to our former CIP detergent and will be attempting to offset the damage to our septic system flora by regularly treating the system with beneficial bacteria treatments. Of course, the long term lesson is that there will always be something to try to improve and compromises made – whether that is in the use of chemicals that are not as “green” as we would like or in costs and time spent trouble shooting problems. Being a small cheesemaker also means being alert and adaptable, there is nothing boring about this career!

Notes:

It is important to remind you that you may not provide testing or plate counts to others unless you are a certified professional working in a certified facility. When first developing a testing frequency protocol, it is advisable to include certified lab testing and consultation with a food safety professional.

Resources:

Supplies: www.nelsonjameson.com

Instructions: www.msu.edu/course/fsc/441/3mapc.html https://www.msu.edu/course/fsc/441/3mc&ec.html,  and http://solutions.3m.com/wps/portal/3M/en_US/Microbiology/FoodSafety/industries/one/

Pressing Cheese without a Form

The “Belly Button” of the cheese

If you’ve ever seen a whole wheel of the iconic US cheese, Vella Dry Jack you might have noticed that the cheese is irregularly shaped and has an indentation on the top that the Vella family fondly dubbed “the belly button”. This cheese, along with several other aged cheeses, are pressed while wrapped in cheese cloth- instead of rigid forms and molds. When I first started making cheese, about 10 years ago, I tried pressing a few small wheels of jack type cheese in this fashion. But I couldn’t figure out how to tie a knot that didn’t make a huge divet (instead of a small belly button) in the wheel.

While doing research and making many different cheese types for my most recent book “Mastering Artisan Cheesemaking” I learned to tie a “Stilton knot”- which is traditionally used to hold Stilton blue cheese curd during draining. The knot enables the cheesemaker to gather and tighten the curd evenly, without tying a bulky knot.  When making a Stilton style cheese, the bundles are formed while the curd is still soft, and sit in the vat while whey drains around them. When making a jack type cheese, however, the bundle is formed after the curd is fully drained and salted. You can use this technique for other types of cheeses as well, even those that are to be brine salted.

To form a Stilton knot, place the curd into the center of a finely woven cheesecloth. Then

After gathering three corners, wrap the 4th around the others, spirally lower, until the knot is tight against the ball of curd

lift and gather three of the corners of the cloth and hold them in one hand. With your other hand take the fourth corner and wrap it around the other three- low and snug to the curd.Make each wrap progressively closer to the curd, this not only tightens the bundle, but also keeps the knot from coming loose. Voila!

I tried it out on one of our “regular” cheeses that we call “Takelma”, a washed curd variety that we usually make in 8 pound wheels. This singular wheel is 24 pounds. After forming the drained curd into a Stilton bundle, I placed a cutting board on top (using short forms at each corner to keep the board from tipping) and then added weight as needed to close the rind and paste.

24 pound wheel after pressing with a food grade board

The wheel reached the correct pH for pressing (in this case 5.2) within a few hours. It was nice to not have to turn the wheel for this type of pressing, and I could easily see that the curd was knitting by looking at it through the cloth (without untying the knot).  After the correct pH was reached, I had a bit of a problem- the wheel was far to large to fit into our usual brine tanks!  Hmm, I thought, and looked around the creamery. There was the vat sitting unused. So I poured in about 3 gallons of fully saturated brine and placed the big cheese down into the solution.  I left the wheel inside it’s bundle and then lifted it into the brine and then unwrapped it- I was concerned that it would crack or break if lifted after unwrapping.

We’ll see how this bigger version ages- as it will be different than it’s smaller derivation. I will core sample it at about 3-4 months and let you all know.

 

Preliminary Assessment FlowChart for Future Farmstead Creameries

Here is another flow chart I created that will walk you through the many considerations you should face before deciding to build a farmstead or artisan cheesemaking business. The red boxes signify a step at which you should stop and assess several factors for suitability, costs, and possible income. If you follow this path, you should collect enough data and information to create a business plan.  From there you can decide for yourself if your plan has merit.

Flow chart for Assessing suitability for building a cheese business

FlowChart- Steps to Licensing a Creamery

Here is a flow chart that may be helpful in seeing the many steps of licensing and permits involved with building a cheesemaking facility. I have focused this chart on California, as it is one of the more “permit heavy” states, but most of the steps will apply in other states as well.