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.

 

Making Yogurt to Feed Kids and Calves

Yogurt  not only provides valuable probiotic bacteria to the young ruminant, but it is easy to digest and can remain at room temperature in free choice bucket feeders without fear of growing unwanted pathogens. Making yogurt for kids and calves is a simple and inexpensive process. At Pholia Farm, we feed pasteurized goat milk and goat milk yogurt blended to a feedable consistency and served in free choice bucket feeders. We make the yogurt in the same manner as one would for personal consumption, but with a little less attention to details such as stray goat hairs and incubation temperature.  Here is how we do it:

  1. Heat milk to 180F
  2. Cool to 130F
  3. Stir in about 1-3 TB per gallon of yogurt from the previous batch or store purchased plain yogurt or use 1/2 tsp of powdered yogurt culture (purchased from a culture supply company such as Dairy Connection)
  4. Place pot in an ice chest to hold temperature- add 125 F water for better temperature control. Even easier, you can simply leave the pot to sit on the counter if the room is fairly warm. The resulting yogurt won’t be quite as thick, but it will work for kids.
  5. After 12 hours the yogurt should be set.
  6. Store in refrigerator.
  7. Don’t forget to retain a bit to start your next batch!

There you have it, bon appetit to your young animals!

Feeding Kids with the Free-Choice, Cool Milk Method- Peace in the Barn!

A few years ago we attempted to raise our Nigerian Dwarf kids on the “cool milk, free-choice” method. This way of feeding kids involves providing full time access to a bucket feeder, or other mechanical nursing unit, stocked with cold or cool milk. The idea behind the method is twofold. First-that kids will not overeat when the milk is cool, and second 24 hour access means they will eat frequent small meals, instead of three or four larger bottle fed meals spaced throughout the day. The end result being an unstressed kid who is also less likely to suffer some of the digestive issues associated with  bottle raising.

Unfortunately, our kids became quite chubby and also had trouble making the switch to solids. By weaning time, we had them back on scheduled feedings in an attempt to increase their intake of roughage. I even tried diluting the milk with an electrolyte solution to keep their weight down. That worked, but the resulting volume of urine meant a lot more pen cleaning and ammonia fumes. So we gave up.

I decided to take another look at what could be done to make this method work for us.  I had loved how quiet the kids were when not hungry between bottle feedings. Not only quiet, but they didn’t mob and molest you every time you entered the pen. You could hold and cuddle a kid without risking a fat lip from their flailing heads and hooves down your shirt as their little legs frantically tried to get them closer to that bottle they just knew you had hidden somewhere. I also wanted to decrease the stress a kid experiences during it’s first two months.

Part of our problem had been coming up with a feeder bucket with nipples that the small mouths of Nigerian Dwarf kids could both start on and continue. Red, Pritchard type nipples are just the right size to start these kids on, but our attempts to make them work on a bucket feeder (as directed by companies selling them as usable on a ball valve, square pale type feeder) failed. No matter what we did, the milk leaked out.  In our first attempt we started them on the Pritchard type nipples mounted on a bucket with a small amount of milk (not enough to cover the top the tube on the inside) and then switched them over to the latex nipples designed to go on these bucket types. (See photo). The latex nipples, however, were often the victim of over eager babies trying to figure them out and would “blow out” at the tips, spilling milk everywhere.  The red, rubber versions were much sturdier, but too stiff for the young goats to figure out. “Caprine” type nipples (the long gray or black kind that fit over a soda pop bottle- or beer bottle as I discovered) were too long for all but the older kids. Too bad, as this type is great for a bucket feeder with a long tube that goes down into the milk.  

Last fall I took a new look at the valve set up for the bottom feeding style of bucket feeders. I wondered if I could add a straw type tube to the inside and drill the holes higher in the bucket. I tried it. It was tough to find a small hose that would fit over the tips, but I finally found latex tubing that I could just barely stretch over the tube. I drilled holes in a new square bucket about one third of the way up and fitted the valves with Pritchard nipples. I put water in the bucket and then, guess what, I tested it and got a nice mouthfull of water!  Pritchard nipples have a little metal valve that provides an air vent, so I sealed these with silicone so that milk would stay in the straw- making it easier for the kids to nurse. Armed with this new type of bucket feeder I  was ready for spring.

We start the kids out on their mom’s for 3 days. Then we switch them to bottles using Pritchard nipples. When they are taking these well, they are placed in a pen with a bucket feeder stocked with warm milk. After they are comfortable with this setting, we let the milk cool and simply let them work through the adjustment. At about four weeks of age, they move to a pen with two larger nipples, a caprine style and a latex lamb bar (see photo above) type nipple. It usually takes a couple times showing them how to use these (I don’t actually demonstrate this myself…) and then they figure it out just fine.  At weaning time, they are moved to a new pen without a bucket feeder, but with a once a day pail of warm water with probiotic powder and  a pinch of electrolytes.

In addition to milk, we feed our kids homemade goat milk yogurt. (I learned this feeding style from the wonderful Jennifer Bice of Redwood Hill Farm). The yogurt is not only great for their health, but when using the cool milk method, it also provides protection from unwanted bacterial growth by acidifying the milk. Not only that, but it makes it thicker and  slows the hungry little buggers down even more!

Between the new buckets and the yogurt mixture, this years kids are quieter, calmer, look great and best of all, not little fatties!

There are some downsides to free choice feeding: You cannot accurately feed a coccidiostat in the milk and must instead medicate them separately; you will waste some milk when the bucket feeder is emptied daily for cleaning (be sure this is done thoroughly to prevent sickness in the kids); and you will end up with a lot of unused baby bottles.