we recorded 6 log cfu/g total bacteria count in cheese. is it normal?
A Fisherbrand Simple Phase Contrast Kit was used to evaluate the samples' total microbial counts.
According to the requirements of the Technical Regulations of the Customs Union (approved in Russia), the permissible total bacteria count in cheese is up to 5.7 log cfu/g. If the bacteria content in cheese is at a level of 6 log cfu/g or higher, such a product is considered spoiled in Russia.
Please clarify what rules apply in your country regarding the total bacteria count content in cheese?
Sergey Karabanov Thank you for your answer. A viable count of 5.4 log cfu/g or higher in my country is considered spoiled.
I would consider what type of cheese it is, how it is packaged and how it was delivered to the laboratory. But I would say that such cheese is spoiled.
Sergey Karabanov you are right several factors should be considered. we repeated our test for mozzarella cheese a few days ago and it seems we made a mistake in our calculation. During the first round we recorded a 6 log cfu/g total viable count, in the second test it was 2.4 log cfu/g.
the cheese was made by us in our lab and based on the safety criteria. we didn't see any spoilage in the sample but the data represent a spoiled mozzarella. However, now we are sure we made a mistake in the calculation.
In my opinion, it would be good to clarify in which cheese the total number of bacteria was determined (hard, soft, processed), because their number varies depending on the type of cheese.
You have to indicate type of cheese, type of starter used, the initial count, the storage time and temperature etc... The important thing is not only TVC, but the presence of
harmful pathogens.
On the other hand, don't forget that starter strains could also increases in number. We add starter for acidity and flavour and hence to do this it will increase in number. TVC is an indicator. It is not the end of story.
Hence, start with good ingredients, perform a good manufacturing procedure, store at the right time and temperature and avoid external contamination factors.
@Vaez Nemati
? Fisher brand Simple Phase Contrast Kit? Can you describe protocol?
To the topic and as with many foods, the total number is not important and here the difference between 6 and 5.7 or 5.4 log is useless bureaucratic pedantry.
As Ali Elsayed Ali said, important is the specific microbe(s)- - Listeria monocytogenes, coliform, E. coli, Staph aureus, Salmonella, etc. https://www.ncbi.nlm.nih.gov/books/NBK221563/