8 replies to this topic

[anna898]

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]

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 -

 

 inactivation C.botulinum.png   94.86KB   9 downloads

 

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

 

The above (Pasteurization) table  gives  Equivalent time/temperature combinations for spores of Non-Proteolytic C. botulinum, Type B.

Notwithstanding the above, the UK viewpoint on Vac, MAP products appears to be that use of any temperatures other than 90degC will necessitate Validation eg Sec.13 in this UK Summary Document.- 

 

 Safety and shelf life Vac-Map packed chilled goods regarding C.botulinum,FSA,2017.pdf   526.33KB   35 downloads

(I also noticed that US seems to have a more flexible attitude regarding shelf-life than UK.)

Edited by Charles.C, 17 May 2022 - 07:09 AM.
edited/corected

[anna898]

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]

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.

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

[Slab]

 

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?

 

 Fish-and-Fishery-Products-Hazards-and-Controls-Guidance-Chapter-16 Pathogen Survival.pdf   1.99MB   26 downloads

 C. Botulinum and Toxin Formation.pdf   888.07KB   37 downloads

 4 Thermal Destruction of Microorganisms (1).pdf   168.96KB   43 downloads

 Applied and Environmental Microbiology-2003-Lindström-4029.full.pdf   131.94KB   29 downloads

 Chapter-3-Cooked-Fish.pdf   657.9KB   18 downloads

 Thermal Death Time.pdf   698.28KB   51 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.

 

 Cook Trial Summary.pdf   448.77KB   36 downloads

 F-value Calculator.xlsx   26.29KB   52 downloads

[Ruben_O]

Hi anna,

 

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

 

inactivation C.botulinum.png

 

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".

 

Actually this table is for non-proteolitic spores. The time temperature combinations given by this table is enough to produce a 6-log reduction of non-proteolitic C. bot. spores found mostly in marine type of products.

The 12D process at 121oC is for proteolitic spores, which are much more heat resistant than the non-proteolitic ones.

[Charles.C]

Actually this table is for non-proteolitic spores. The time temperature combinations given by this table is enough to produce a 6-log reduction of non-proteolitic C. bot. spores found mostly in marine type of products.

The 12D process at 121oC is for proteolitic spores, which are much more heat resistant than the non-proteolitic ones.

Hi Ruben_O,

 

Thanks yr input. You are absolutely correct. I have emended Post 2 accordingly.

 

One large review (see below) of existing (non-proteolytic) data suggests heating requirements may vary with operational methods, etc although the long established 90degC/10min combination is still supported.

 

 heat resistance of non-proteolytic C. botulinum, 2016.pdf   976.3KB   17 downloads

 

This, quite readable, recent  thesis compares heat resistance data on both proteolytic and non-proteolytic strains.

 

 Heat Resistance of 7 Strains of C.botulinum Spores,2019.pdf   1.56MB   20 downloads

[PhilA]

Hello,

 

I am looking for the F value for home canning in a pressure canner the TDT (thermal death time) for C Botulinum spores. I understand that a 12-D cook for Cl. botulinum may require an F value of 2.52, this at a temp of 121C.

 

My question is what is the TDT for a temp of 240F?

 

My canner operates at 15psi and previously canned green beans have maintained temps between 240-250 for 20 mins. Is this enough? Is there a standard? I am using a Lascar datalogger inserted inside the pint jar of green beans throughout the pressure canning period.

 

Can you help me to understand this?

 

[Slab]

Hello,

 

I am looking for the F value for home canning in a pressure canner the TDT (thermal death time) for C Botulinum spores. I understand that a 12-D cook for Cl. botulinum may require an F value of 2.52, this at a temp of 121C.

 

My question is what is the TDT for a temp of 240F?

 

My canner operates at 15psi and previously canned green beans have maintained temps between 240-250 for 20 mins. Is this enough? Is there a standard? I am using a Lascar datalogger inserted inside the pint jar of green beans throughout the pressure canning period.

 

Can you help me to understand this?

 

Hi, Phil;

 

It really depends on many equipment and environmental factors, and the product you wish to heat treat. The USDA has published several documents for home canning and can be found here;

 

https://nchfp.uga.ed....html#gsc.tab=0