What tests should be carried out to determine shelf life?

Hi. Pick your brain time..... What tests should I be carrying out on product, and determination of product shelf life. We are raw veg and prepared veg suppliers i.e. single item veg dice and slice and also things like soup mix, veg mix , coleslaw mix etc.

Greetings,

TVC (or APC or ACC depends which term you use), Enterobacteriaceae and Yeasts/Molds (and maybe E. coli for your RTE vegetables and L. monocytogenes if you are in Europe), for shelf life test, starting from the time the packed product is out of your production. These don't actually have limits, as what you want to see is the difference from day 0 up to the end-date that you approximately set. In this study what you don't want to see is m/o peaking or better were the trend line of microbial growth starts showing an incline (zero Listeria of course, no trends no nothing at all for this one). You also have to take into account the organoleptic charecteristics of your product during shelf-life test.

For your regular tests on raw materials and end products you should go for TVC, Ent/ceae, E. coli (< 100 - EC 2073/2005), Staphylococcus, Salmonella  (0 /25g - EC 2073/2005), Listeria (0/25g - EC 2073/2005).

EC 2073/2005 is EU legislation to give an example, as location --> earth is a bit vague!

Hi

Thanks for your feedback....

At what criteria would you look at for TVC and Ent.

Would you not test for Pseudos' for a spoilage marker?

Since there are no limits you have to bear in mind that the shelf-life is closely related to organoleptic characteristics. Having established that, usually raw vegetables start with (all values are approximations from averages) TVC 10⁴ cfu and Ent. 200-800 cfu. In the end of their shelf-life these numbers rump up to 15-20*10⁴ and 5*10³ respectively, but when you are nearing these values you also detect clear organoleptic signs of spoilage (visual, smell etc).

Pseudo is not so commonly found in ground to be used as a spoilage indicator, but if you wanna test for it, then it would be better if you tested the waste water you get from the vegetables washing, cause if Pseudo does exist it will be in high enough concentrations to be detected.

Hi. Pick your brain time..... What tests should I be carrying out on product, and determination of product shelf life. We are raw veg and prepared veg suppliers i.e. single item veg dice and slice and also things like soup mix, veg mix , coleslaw mix etc.

See the parallel post/thread linked below. It likely follows the same logics - 

https://www.ifsqn.co...on/#entry172085

Edible Products - Prep

 

Edible Products - Prep

TVC >108

E. coli>102

Salmonella Detected in 25g

Listeria Detected in 25g

 

Shelf Life

TVC >108

Entero>106

Psedo

Salmonella Not Detected in 25g

Listeria Not Detected in 25g

E. coli Not Detected in 25g

 

Environmental Swabs

TVC >3x104

Entero >103

 

Hi

 

My limits are above currently for our products and environment.

 

Has anybody got any comments please

 

 

 

 Hi astro,

Afraid there's a few howlers. JF example -

> should be <

Listeria should be L.monocytogenes and there's a "not" missing.

Similarly Salmonella.

TVC looks astronomic (twice)

Entero is astronomic/high. (better to specify proper name).

Psedo does not exist afaik

E.coli (if generic form) unbalanced.

Produced by a non-microbiologist/non-mathematician ?

I suggest to compare to UK, RTE guidelines if data qiven.

PS - if I understand their data correctly, the UK guidelines seem to prefer no measurement/specification for APC of raw, prepared, RTE vegetables.

Hi

Thanks....

I will try again - again this is for product which will be further processed except possibly grated carrot, onion, peppers

Edible Products - Prep

Hi astro,

Not sure what yr exact Product composition /storage etc is but, based on the UK Guideline data which I have compiled in attached Excel file, I (speculatively) suggest -

Product Microbiological Specification (at Point of Sale)

Generic E.coli < 100 cfu/g

Pathogenic E.coli  - Not detected in 25g

**Listeria spp < 100cfu/g

L.monocytogenes < 100cfu/g

Salmonella  - Not detected in 25g

B.Cereus and other Pathogenic Bacillus spp < 10,000cfu/g

**Enterobacteriaceae < 10,000cfu/g

** - optional but does not represent a defined species.

Pseudomonads/spoilage are briefly mentioned in source refs but no limits suggested so maybe preferable to "avoid".

UK Guidelines Microbiological Quality-Safety RTE Foods, 1.1 .xls   2.17MB   49 downloads

Hi

Thanks for this.

You say option for Entero but surely you would test this on surface testing to validate cleaning?

Hi

 

Thanks for this.

 

You say option for Entero but surely you would test this on surface testing to validate cleaning?

Hi astro,

The EB value given (<10⁴ cfu/g) referred to the Product (eg compare yr Post 6), not food contact surfaces (fcs). Was noted as "Optional" due it is not a defined species and is often not included in Product Specifications.

For fcs, the typical, afaik current, UK/Guidelines (eg EB <1cfu/cm²) are given in the excel in this post - 

https://www.ifsqn.co...ces/#entry60958

(Just to illustrate Global diversity, a US Guideline in same Table is 10x(UK) !)

(EB is popular in UK, less so in some other locations).

PS - the UK-APC-fcs Guideline value quoted in excel is IMEX also rather optimistic (can compare my introductory thoughts to the excel).

Hi astro,

JFI, this is the decision tree which I based my initial shelf life /  L.mono comments on. Tree is quite old (2006) but afaik is still essentially current although the (non-free) updated UK/CFA chilled foods text book (or FSA website) are probably definitive.

Decision Tree, L.monocytogenes.pdf   593.56KB   33 downloads

Hi. Pick your brain time..... What tests should I be carrying out on product, and determination of product shelf life. We are raw veg and prepared veg suppliers i.e. single item veg dice and slice and also things like soup mix, veg mix , coleslaw mix etc.

I see others have focused perhaps exclusively on microbiology, and that angle is well-covered, so here are my general thoughts.  There are some main categories  of attributes when it comes to shelf life:  microbiological stability of course, then organoleptic stability (color, odor, taste), and potency stability.  It doesn't look like potency stability would apply here necessarily, so that leaves color, odor, and taste.  I would evaluate for those in addition to the tests that others have mentioned.

Matthew

I see others have focused perhaps exclusively on microbiology, and that angle is well-covered, so here are my general thoughts.  There are some main categories  of attributes when it comes to shelf life:  microbiological stability of course, then organoleptic stability (color, odor, taste), and potency stability.  It doesn't look like potency stability would apply here necessarily, so that leaves color, odor, and taste.  I would evaluate for those in addition to the tests that others have mentioned.

 

Matthew

Hi Matthew,

Afaik the first priority in UK is safety (may be different in US labelling?). This typically determines a labelling UK-"Use By". If no significant micro safety parameters exist eg frozen product, organoleptic or (non-safety)chemical items usually come into play together with a labelling "Best Before". Regardless the CP items are still covered by the compliance with specification at end of shelf life requirement.