The Bacteria in Parmigiano Reggiano

Cheese is a product of fermented milk. For fermentation to occur, we will need a huge diversity of bacteria population to help.

Sometimes inevitably, the bad one as well.

Under the microscope, various kind of bacteria work together to eat up (process) the milk. Also, the presence of certain bacteria is geographical. That is why Parmigiano Reggiano made from different places will give out a different taste, aroma, or texture. See example here.

In fact, the longer the aging process (may take up years) the “better” the taste, therefore higher the price see latest price here.

During the cheesemaking process, you will normally see the salt being mixed or brined with the cheese.

That is an essential step to get rid of the unwelcoming harmful bacteria at bay, but having the good one inside overgrown. Plus, it adds a bit of saltiness to the mild taste.

Ahh, taste better now..

Oh don’t forget, if you ever tasted the weird “umami” taste, read my other article here.

What’s hidden in the Parmigiano Reggiano

One excellent example would be the Parmigiano Reggiano.

Parmigiano Reggiano has been known to be one of the best cheese that can only be made in a specific region in Italy.

And that’s because of the presence of the certain type of bacteria in that region, which got eaten by cows and made their way into the milk, and later the cheese production.

These bacteria are naturally present in the grass and whey.

A whey starter (the remains of the previous day) will also be added into the milk to increase the bacteria counts.

This image showed the bacteria grew on one of the agar media. The white dots being the colonies of bacteria.

How many type of bacteria?

Studies (1, 2) have found over 180 strains of bacteria present throughout the Parmigiano Reggiano’s cheesemaking process.

These normal-to-high temperature ranges of (thermophilic and mesophilic) bacteria have their population changes in different stages.

Overall, the lactic acid bacteria has a dominant population.

They resist the growth of other microbes.

Respectively, they were found in different numbers throughout the 6hr/12hr/48hr of curd stage, in the raw milk and whey starter, cheese stage, and brined cheese stage.

But wait,

the white spots might not be a mold at all, read my explanation here.

Below are the different species of bacteria involved in the process:

  1. Lactobacillus delbrueckii 
  2. Lactobacillus helveticus
  3. Lactobacillus casei
  4. Lactobacillus brevis
  5. Lactobacillus paracasei 
  6. Lactobacillus rhamnosus
  7. Lactobacillus plantarum 
  8. Lactobacillus fermentum
  9. Lactobacillus parabuchneri
  10. Pediococcus acidilactici
  11. Kocuria kristinae
  12. Lactococcus lactis
  13. Enterococcus faecium
  14. Enterococcus faecalis
  15. Streptococcus thermophilus

When and where they showed up?

To be exact, the thermophilic lactic acid bacteria (~113°F) such as the Lactobacillus helveticus and Lactobacillus delbrueckii were both found predominantly in the ingredients (milk, starter, whey, and curd) and also in the first 2 weeks of aging (3).

The number of them slowly reduces from there onward, and the mesophilic bacteria (~72°F) started to kick in and increased in population, which includes Lactobacillus casei, Lactobacillus rhamnosus, and Pediococcus acidilactici.

Some of the bacteria also responsible for the feet/sock/vomit smell, like here in feta explained.

There are other bacteria maintained mostly constant in number throughout the cheesemaking process, Lactobacillus paracasei for example.

So, with the bacteria known, why can’t we replicate the exact cheesemaking recipe elsewhere?

Without all these, the appreciated cheese can’t be called DOP Parmigiano Reggiano.

Even if we have these bacteria cultured in the lab, we still can’t replicate Parmigiano Reggiano elsewhere in the world.


It’s simply because of these bacteria is not all, but part of a myriad microorganism that takes part in the unique ecosystem in Reggio Emilia, Italy.

Most of the current study focuses on a number of specific species of bacteria. The rest remained largely to be understood.

Other Parmigiano Reggiano in the market, also called the “fake” Parmesan cheese, that made in different places outside of the DOP region will have similar bacteria in it, but will not be the exact same taste.

Have you ever seen a less appetising blue cheese which fully covered in mold? It’s actually quite normal to cheesemaker, see picture and read here.