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D value for C Botulinum


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anna898

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Posted 05 October 2020 - 10:15 AM

HI All

I'm looking for an alternative cooking time/temp to 90C/10min to eliminate C Botulinum spores. Historical data and many research suggests 90C for 10min to get rid on non-proteolytic C. Botulinum from the seafood products. 

I have no idea how to calculate the d value for 100C. 

 

Any help?



Charles.C

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Posted 05 October 2020 - 11:28 AM

HI All

I'm looking to alternative cooking time/temp to 90C/10min to eliminate C Botulinum spores. Historical data and many research suggests 90C for 10min to get rid on non-proteolytic C. Botulinum from the seafood products. 

I have no idea how to calculate the d value for 100C. 

 

Any help?

Hi anna,

 

The calculation was done many years ago and the results tabulated for you -

 

Attached File  inactivation C.botulinum.png   94.86KB   1 downloads

 

The calculation is done via the formulae linking D, z and T.

 

Note the above refers to vegetative bacteria/pasteurization.

 

Removal of spores requires sterilization and a 12D "cook".


Kind Regards,

 

Charles.C


anna898

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Posted 05 October 2020 - 11:48 AM

Thank you Charles

Do you know by any chance if there is any regulations which states what heating process must be used for seafood products( prawns/ shrimps), We blanch them ( in shell) soon after harvest ( 6-7 min at 100C), then hand pick and blanch again. As they are not deep waters but more coastline I've found some research suggesting that they are a potential source of C botulinum thus require 90C for 10 mins heat treatment or equivalent. I cant find any references in law ( UK) as to specific processing parameters. Do you think that blanching is enough or we should cook for longer?



Charles.C

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Posted 05 October 2020 - 12:53 PM

Thank you Charles

Do you know by any chance if there is any regulations which states what heating process must be used for seafood products( prawns/ shrimps), We blanch them ( in shell) soon after harvest ( 6-7 min at 100C), then hand pick and blanch again. As they are not deep waters but more coastline I've found some research suggesting that they are a potential source of C botulinum thus require 90C for 10 mins heat treatment or equivalent. I cant find any references in law ( UK) as to specific processing parameters. Do you think that blanching is enough or we should cook for longer?

I have encountered 2 approaches to RTE shrimp cooking. One is to only do a cook on the whole shrimp as against yr method using 2 heat treatments.

 

I think the choice is particularly based on the quality/value of raw material and subsequent handling processing (ie spoilage-contamination-related criteria/automation). The second method is IMEX standard where the shell-on blanching is at a different location to final processing. Obviously there is a weight benefit for one step.

 

afaik, C.botulinum mainly comes into play where ROP packaging or maybe sous-vide processing involved but I suppose a specific risk in the raw material could relate. There is an extensive/useful discussion on C.botulinum in the well-known US-Fishery Hazards Book. You can also see some examples there of crabmeat where only one cook step is done.

 

afaik in Europe/UK, the "final" cook is typically based on 6D for L.monocytogenes (eg minimum or equivalent to 2min/70degC core). As I understand, USA  tend to have a different opinion (more nervous about Salmonella). Some European countries have target micro. criteria other than L.monocytogenes (more demanding with respect to Lethality).

 

afaik UK does have generic, legal, retail, cooking requirements. Probably includes shrimp.

 

You need some data to make predictions. :smile:


Edited by Charles.C, 05 October 2020 - 01:23 PM.
edited

Kind Regards,

 

Charles.C


Slab

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Posted 05 October 2020 - 01:09 PM

 

Do you know by any chance if there is any regulations which states what heating process must be used for seafood products

Good morning;

 

May I ask what is the final form of your product (including package type)?

 

I don't believe there is any regulatory "approved" process methods, only that you have established statistical repeatability of the process where End Process Internal Product Temperature (EPIPT) is achieved and that established process controls are verified, or EPIPT is verified. You will have to establish a thermal process study with the Z and F values and reference temperature provided in the table by Charles. Perhaps you have a food science engineering cadre at your local university that can assist?

 

Attached File  Fish-and-Fishery-Products-Hazards-and-Controls-Guidance-Chapter-16 Pathogen Survival.pdf   1.99MB   13 downloads

Attached File  C. Botulinum and Toxin Formation.pdf   888.07KB   13 downloads

Attached File  4 Thermal Destruction of Microorganisms (1).pdf   168.96KB   14 downloads

Attached File  Applied and Environmental Microbiology-2003-Lindström-4029.full.pdf   131.94KB   11 downloads

Attached File  Chapter-3-Cooked-Fish.pdf   657.9KB   9 downloads

Attached File  Thermal Death Time.pdf   698.28KB   15 downloads

 

Below is a summary from a thermal study I conducted last year for a crab processor, and the F-value calculator used. Of course this is only a loose guide and you will have to tailor your study specifically to your process. This particular study was observed, and the data reviewed by a professor of food sciences at a local university.

 

Attached File  Cook Trial Summary.pdf   448.77KB   20 downloads

Attached File  F-value Calculator.xlsx   26.29KB   18 downloads


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