How Can You Tell if Probiotics are Alive and Active?

Our gastrointestinal tract is home to trillions of microbes. A balanced microbiome helps keep us healthy, energetic, and in a good mood.

Probiotics contain a combination of live beneficial microorganisms that provide physiological benefits to our health. Primarily, these are good bacteria that are naturally occurring in fermented foods.

While probiotics are present in a variety of foods, they are also commonly consumed as a dietary supplement. If you’ve purchased a probioitic supplement, you might be wondering, “How do I know if my probiotics are still alive and active?

Viability Tests for Probiotics

In order for you to experience the benefits of a probiotic supplement, it’s important that the probiotics are “viable” – a scientific term that basically means the probiotics are alive and active.

There are two main ways to test probiotics for viability: lab testing, and the popular at-home “milk test.”

Microbiological Lab Testing

Laboratories use Colony Forming Unit (CFU) as their measure to evaluate the potency of a probiotic product.

There are three primary methods used by labs to test probiotic viability. They are:

1. Selective Enumeration

With selective enumeration, organisms are examined to see if they are alive and present in adequate amounts. Microbiologists identify the existing probiotic organism(s) and count the colony forming units (CFU) in a product. 

2. Species Specification

In species specification, laboratories ensure the quality of the product using culture morphology and DNA sequencing methods. With these methods, they are able to confirm existing specific target probiotic microorganisms.

3. Reveal Survivability

Reveal survivability involves testing the viability of the probiotic microorganism through monitoring its survival. This process occurs over a product’s expected shelf-life under various storage conditions.

The Milk Test 

Ok, great, you might be thinking – but what if I don’t have access to a microbiological lab? A common next step is to try the “milk test” (however, make sure to continue reading to hear our take on its reliability).

The milk test is a popular at-home process used to test the viability of probiotics. To complete the milk test, all you need is 4 oz. of cold milk along with your probiotic supplement. The steps are:

  1. Prepare 4 oz. of cold milk then add the probiotic supplement.
  2. Keep the glass at room temperature and leave it for a day or two. 
  3. Check the milk for clump formation as time has passed. 

The milk test supposedly shows that the probiotic product that you purchased is viable if the milk curdles, or if it creates a yogurt-like consistency.

How Does the Milk Test Work?

Clump formation occurs in the milk test when the liquid becomes acidic. This is due to the presence of probiotics that can ferment lactose into lactic acid.

Commonly, the probiotic bacteria that can convert lactose to lactic acid are from the genus Lactobacillus. The more lactic acid is produced in the milk, the more it forms clumps.

Unfortunately, not all probiotic bacteria causes milk to curdle. The Bifidobacterium family of probiotic, for example, frequently fails the milk test since its environmental condition requires a small amount of oxygen for it to be able to turn milk acidic.

Is the Milk Test Reliable?

Many consumers ask if the milk test is a valid way to examine if the probiotics in certain products are alive and active. The official professional answer is no.

Though it can be done at home, it is not a particularly reliable method to check the viability of a probiotic supplement – even if the milk curdles quickly. 

While the milk test is commonly used in a pinch at home, if you need to reliably determine if your probiotics are truly active you’ll need to consult a lab.

This is particularly important if you’re using probiotics to treat any sort of medical condition. Once again, the only officially reliable method to determine their viability is to consult a medical professional at a laboratory.

Benefits of Probiotics for Gut Health

Probiotics come in different strains of bacteria, each accompanied by different beneficial effects. For example, some bacterial strains help fight against cavities in oral health, but they can’t thrive in the gut.

Research has shown the potential of probiotics to aid in the treatment or prevention of diarrhea, ulcerative colitis, irritable bowel syndrome, ulcers, vaginal infections, Crohn’s disease, urinary tract infection, and eczema in children.

Signs of effective probiotics include:

1. Regular bowel movement

Probiotic supplementation can ease bowel movement and reduce belching, bloating, and general abdominal fullness. The good bacteria in probiotic supplements helps move food smoothly through the digestive system.

2. Less digestive discomfort

Probiotics aid in the digestion of food, and ease symptoms of gastrointestinal distress

3. Improved mood

Imbalance of the gut microbiome causes inflammation. This condition results in the release of inflammatory chemicals that interact with nerve cells – potentially causing mood changes, stress, and anxiety.

Certain strains, such as Lactobacillus helveticus and Bifidobacterium longum, may have a significant effect on reducing anxiety and depression symptoms (as shown in this 8-week intervention study)

4. Weight loss

Research into the association between gut health and obesity suggests that taking probiotics (specifically, those containing Lactobacillus rhamnosus and Bifidobacterium lactis) can help with weight loss.

5. Improved glycemic index and cholesterol levels

Studies have shown that taking probiotics can help reduce the risk of cardiovascular diseases and blood sugar levels.

In another 6-week intervention study conducted on type 2 diabetic patients, probiotics decreased the patients’ concentration of total triglyceride and IL-6 level. However, further research is needed to verify the therapeutic effects of probiotic on patients with diabetes.

How to Select a Probiotic Supplement

If you’re supplementing with probiotics, there are some things you can do to help ensure they stay alive and active. Look for a supplement with these features:

  • Dosage in the billions. Choose a supplement that contains billions of good bacteria.  In a 2008 study, it was shown that the adverse effects of probiotics are uncommon. Probiotic dosage for children ranges from 5 to 10 billion CFU per day, with a recommended daily dosage of 10 billion CFU or more for adults.
  • Multiple strains. In my opinion, the more strains the product has, the better. Since the human microbiome is diverse, I recommend choosing a probiotic supplement with more than strain.
  • No binders or fillers. Check the ingredients carefully! Some products contain lactose or cornstarch as binders and fillers. These ingredients can cause you to experience gas or bloating. 

No matter which supplement you choose, make sure to review the “expiration” or “use by” date. One of the best things you can do to make sure your probiotics are alive and active is to completely use the product before the expiration date.

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