# Need some help with food microbiology calculation

5 replies to this topic

### #1 ft.tgif

ft.tgif

• IFSQN Active
• 5 posts
• 0 thanks
0
Neutral

• Malaysia

Posted 26 January 2021 - 01:42 PM

Hi all, I am currently evaluating this raw material to be purchased. The microbiological specification of Yeast = max 100CFU/g. While our finished product specification for Yeast is max 20CFU/g. Our manufacturing process will use 2.8g of this raw material, and it’s added into a mixture of all other ingredients which sums up to 306g. So this raw material I’m referring to is only (2.8/306)x100% = 0.92% of the finished product. There will be no processes like heat treatment or anything to further reduce microbiological contents. Assuming all other raw materials and environmental microbiological specs/values are absolute zero. If my 2.8g of raw material that is going to be added into the finished product which makes up to a total weight of 306g, has Yeast = 100CFU/g, does this mean the yeast in my 306g finished product is gonna be 0.92% x 100CFU/g = 0.92CFU/g? Is my calculation here correct? I just need reassurance that the way I’m doing is correct, or can someone explain to me how can I know how much of the microbes from this particular raw material will end up in my finished product without doing an actual lab analysis?

### #2 Charles.C

Charles.C

• IFSQN Moderator
• 18,311 posts
• 5129 thanks
1,129
Excellent

• Earth

• Gender:Male
• Interests:SF
TV
Movies

Posted 26 January 2021 - 06:15 PM

Hi all, I am currently evaluating this raw material to be purchased. The microbiological specification of Yeast = max 100CFU/g. While our finished product specification for Yeast is max 20CFU/g. Our manufacturing process will use 2.8g of this raw material, and it’s added into a mixture of all other ingredients which sums up to 306g. So this raw material I’m referring to is only (2.8/306)x100% = 0.92% of the finished product. There will be no processes like heat treatment or anything to further reduce microbiological contents. Assuming all other raw materials and environmental microbiological specs/values [for yeast] are absolute zero. If my 2.8g of raw material that is going to be added into the finished product which makes up to a total weight of 306g, has Yeast = 100CFU/g, does this mean the yeast in my 306g finished product is gonna be 0.92% x 100CFU/g = 0.92CFU/g? Is my calculation here correct? I just need reassurance that the way I’m doing is correct, or can someone explain to me how can I know how much of the microbes from this particular raw material will end up in my finished product without doing an actual lab analysis?

It might be advisable to determine the actual microbial level of yeast in yr raw material. And its variability.

Some potential hypothesised calculation snags -

(1) Yr logic assumes cells are uniformly distributed throughout the materials. In practice there will be distributions and sampling error..

(2) There may be microbial growth ?.

(3) Why would ^^^(red) be true ?

Kind Regards,

Charles.C

### #3 juanolea1

juanolea1

• IFSQN Active
• 6 posts
• 4 thanks
2
Neutral

• United States

Posted 27 January 2021 - 12:14 AM

In theory thats seems correct, it's about 1 to 100 dilution of the starting material. However, like someone else mentioned, it makes more sense to send the ingredient to a lab to get an actual yeast/mold count (number). The lab result may be well below the specified number.

### #4 juanolea1

juanolea1

• IFSQN Active
• 6 posts
• 4 thanks
2
Neutral

• United States

Posted 27 January 2021 - 12:27 AM

Also, remember that microbiological testing may have a limit, most labs can test y/m to above 10cfu/g.

### #5 ft.tgif

ft.tgif

• IFSQN Active
• 5 posts
• 0 thanks
0
Neutral

• Malaysia

Posted 27 January 2021 - 01:23 AM

It might be advisable to determine the actual microbial level of yeast in yr raw material. And its variability.

Some potential hypothesised calculation snags -

(1) Yr logic assumes cells are uniformly distributed throughout the materials. In practice there will be distributions and sampling error..
(2) There may be microbial growth ?.
(3) Why would ^^^(red) be true ?

Thanks all for the reply. I just needed to confirm my theory on this. I am fully aware that the scenario I gave won’t be realistic as that’s just not how it would work in the real world with all the external factors. But we are just trying to filter out the raw material with specs that we do not even want to consider running a trial. Like if based on theory, if the raw material specs would directly cause our finished product to be out of spec, or is getting very close to our maximum spec for finished product, then why would we even want to waste resources on doing a trial and all the lab tests in the first place. We would prefer to go with something that we are assured that it won’t be out of spec based on theoretical assumptions, and then we will do an actual trial run with it to ensure everything is good because of many other external factors that were mentioned by all commenters here.

### #6 Charles.C

Charles.C

• IFSQN Moderator
• 18,311 posts
• 5129 thanks
1,129
Excellent

• Earth

• Gender:Male
• Interests:SF
TV
Movies

Posted 27 January 2021 - 06:09 AM

Thanks all for the reply. I just needed to confirm my theory on this. I am fully aware that the scenario I gave won’t be realistic as that’s just not how it would work in the real world with all the external factors. But we are just trying to filter out the raw material with specs that we do not even want to consider running a trial. Like if based on theory, if the raw material specs would directly cause our finished product to be out of spec, or is getting very close to our maximum spec for finished product, then why would we even want to waste resources on doing a trial and all the lab tests in the first place. We would prefer to go with something that we are assured that it won’t be out of spec based on theoretical assumptions, and then we will do an actual trial run with it to ensure everything is good because of many other external factors that were mentioned by all commenters here.

It's a question of semantics.

A hypothesis is either a suggested explanation for an observable phenomenon, or a reasoned prediction of a possible causal correlation among multiple phenomena. In science, a theory is a tested, well-substantiated, unifying explanation for a set of verified, proven factors. A theory is always backed by evidence; a hypothesis is only a suggested possible outcome, and is testable and falsifiable.

https://www.diffen.c...hesis_vs_Theory

So yes, yr hypothesis could be correct if all yr (explicit/implicit) assumptions are realised.

Kind Regards,

Charles.C

#### 0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users