14 replies to this topic

[Yeeling]

Hi all,

 

Merry Christmas to all..but i believe now is celebrating boxing day!!

 

I have some trouble in setting up accelerated shelf life study for a snack food. Although i have read through some articles that I could refer to Q10 to estimated the shelf life, I would need more explanation and guidance in setting up my study. I have also known that it is important to identify the factor that could cause deterioration for my product.

 

But is there any proper procedure to let me know what temperature should i store my sample, how long do i need to keep my sample? 

 

Really hope someone could help if you have conducted any stability study on snack food eg biscuits, cookies

 

Thank you very much!!!

[Charles.C]

Hi all,

 

Merry Christmas to all..but i believe now is celebrating boxing day!!

 

I have some trouble in setting up accelerated shelf life study for a snack food. Although i have read through some articles that I could refer to Q10 to estimated the shelf life, I would need more explanation and guidance in setting up my study. I have also known that it is important to identify the factor that could cause deterioration for my product.

 

But is there any proper procedure to let me know what temperature should i store my sample, how long do i need to keep my sample? 

 

Really hope someone could help if you have conducted any stability study on snack food eg biscuits, cookies

 

Thank you very much!!!

 

Hi Yeeling,

 

I have not personally conducted any ASLTs but can offer some info. gleaned from the net, etc.

 

The details will likely relate to yr specific item so i have generalised.

 

I assume product is shelf-stable at room temperature (ca 25degC).

 

If no previous knowledge will be necessary to do a preliminary study by storing product at relatively high temperature so as to estimate the maximum storage time at room temperature.

For example production of new item X with no previous knowledge of shelf life.

(a) Store samples at 45degC and control samples at 4degC.

(b) Every 3-4 days test sample at 45degC versus control using a  panel of 3-4 assessors to conclude by consensus.

 

As example, consider that  item X at 45degC has a clear off-flavor after 25 days storage. Assume a general value for Q10 of 2.5. So an approx. maximum storage time at 25degC would be 156 days (25x2.5x2.5).

Should prepare/store enough samples at 25degC to cover 7 months storage since 156days  liable to significant error/confidence interval.

 

Having done the preliminary survey, refinements are possible, ie a more precise re-evaluation of Q10/shelf life. This is illustrated in the enclosed document together with a parallel project to increase the shelf life of a snack food -

 

 Conducting a shelf-life-study.pdf   2.53MB   513 downloads

[Yeeling]

Dear Charles,

Thanks for your reply. Do you have any guidance to show how to derive Q10? As referring to your note, i shall define my Q10 and set the parameters needed to study my product.

Thanks.

[Charles.C]

Dear Charles,

Thanks for your reply. Do you have any guidance to show how to derive Q10? As referring to your note, i shall define my Q10 and set the parameters needed to study my product.

Thanks.

 

Hi Yeeling,

 

The derivation is quite involved mathematically. I suggest you consult a food text book for shelf life..

[Ryan M.]

You can use any Q10 temperature you want, but you also need to do side by side comparison against your control temperature which is the normal temperature you expect the product to be stored, distributed, held.

 

Do you have any specific temperatures ranges that are readily available to you?

 

Your Q10 could vary greatly on each product as well depending on the make-up of your bakery items.

[FurFarmandFork]

You have to determine Q10 on an item by item basis based on experimental observation, running your shelf life study side by side and seeing what kind of acceleration you get.

 

If you use microbial parameters, in their webinar "Solving the shelf life study", which unfortunately isn't available as a recording, MXNS provided some general microbial criteria (text from slide copied below).

 

"How do we know when a product has reached the end of its shelf life?

 

Microbial Quality/Spoilage organisms

General acceptance criteria

Bacterial load: 10,000,000 CFU/g

Yeast: 100,000 CFU/g

Visible Mold Spoilage

 

Tends to be associated with off flavors, odors, slime, may be a slight lag in sensory defects.

Product/packaging specific"

[Charles.C]

You have to determine Q10 on an item by item basis based on experimental observation, running your shelf life study side by side and seeing what kind of acceleration you get.

 

If you use microbial parameters, in their webinar "Solving the shelf life study", which unfortunately isn't available as a recording, MXNS provided some general microbial criteria (text from slide copied below).

 

"How do we know when a product has reached the end of its shelf life?

 

Microbial Quality/Spoilage organisms

General acceptance criteria

Bacterial load: 10,000,000 CFU/g

Yeast: 100,000 CFU/g

Visible Mold Spoilage

 

Tends to be associated with off flavors, odors, slime, may be a slight lag in sensory defects.

Product/packaging specific"

 

Hi Earth,

 

Love the "General acceptance" bit.

Possibly for many RTE materials, well past the end life ? (I think one of the requirements of a usable shelf-life prediction is that the micro.data must comply with the product specification).

A little validation would be useful.

[FurFarmandFork]

Oh I'm sure you've lost a ton of other characteristics by the time you get to that point, there's also the problem that you may have a death phase in microbial growth before reaching those values based on the nature of the packaging or available oxygen, making it never expire!

 

Agree with you that those should be based on products produced within target initial microbial spec. There's a ton of ways to be conservative, base shelf life on observed exponential growth rate, assume no deaths and set that as shelf life of the product when it hits those target values etc. I would only use those values if growth was 1st non-pathogenic, and 2nd didn't cause a sensory or other defect before hitting those values. LAB (lactic acid bacteria) have a way of making themselves known at much lower CFU.

[Charles.C]

Hi Earth,

 

Thks yr comments. It’s an interesting topic albeit highly complicated.

 

JFI I did a little searching –

 

The slide quote looks similar to following pair of extracts (2007, 2014 respectively). It appears that such  “count”  generalisations  have well-infiltrated the shelf-life literature. (It is also possible the slide was discussing a specific food scenario ?)

 

Shelf-life is defined as the period of time during which the quality of a food product remains acceptable for consumer consumption. At the end of shelf-life, the fresh quality of the food product is unacceptable or undesirable due to changes in taste, texture, aroma, color and appearance. Organoleptic qualities of the food begin to change as the spoilage bacteria, yeast or mold in the food grow. End of microbiological shelf-life may be determined based microbial counts. The number of organisms required to cause spoilage varies with the type of the organisms. Generally, however, it is accepted that 10 million bacteria per gram, 100,000 yeast per gram, or visible mold indicates the end of microbiological shelf-life.

 

 Shelf-Life concepts.pdf   34.07KB   222 downloads

Microorganisms  must multiply to certain levels in order to be able to cause food spoilage.

This is referred to as spoilage detection level

 Bacteria and yeasts  need to grow and reach 10(7) cells/g,ml or cm(2).

 The spoilage detection level can range from 10(6)-10(8) cells/g, ml, or cm(2).

 microbial food spoilage.ppt   363.5KB   157 downloads

 

I anticipate that all the above proposals are valid for certain specific food situations/“counts” but are probably (sadly) quantitatively lacking  as general limits based on, say, APC. Some texts do offer (numerous) caveats for certain "counts" whose compliance may usefully predict spoilage in certain foods.  As an example can see these relatively more "defined"  suggestions (2010)  –

 

 suggested shelf-life micro criteria,2010.png   108.82KB   4 downloads

Nonetheless some foods (for hypothesised reasons) seem only classifiable as “exceptions”, eg this detailed shelf-life study (2001) -

 

The loss of sensory quality of the milk followed a log shelf life vs. temperature dependency.  It was found that there was no correlation between the microbial count at the end of shelf life and the sensory quality of the milk.  It is therefore suggested that microbial counts should not be used to determine the sensory shelf life of milk.

 shelf life of milk.pdf   201.43KB   119 downloads

[Yeeling]

You can use any Q10 temperature you want, but you also need to do side by side comparison against your control temperature which is the normal temperature you expect the product to be stored, distributed, held.

 

Do you have any specific temperatures ranges that are readily available to you?

 

Your Q10 could vary greatly on each product as well depending on the make-up of your bakery items.

Hi Ryan,

 

I am planning to do an accelerated study on my snack at 40 degree Celsius. But I believe in order to get the Q10 for my product, i shall conduct a few trials. In my case, I do not study my product at different temperature, thus I assume my Q10 is 2. Is it a valid method?

 

Thanks.

[Charles.C]

Hi Ryan,

 

I am planning to do an accelerated study on my snack at 40 degree Celsius. But I believe in order to get the Q10 for my product, i shall conduct a few trials. In my case, I do not study my product at different temperature, thus I assume my Q10 is 2. Is it a valid method?

 

Thanks.

 

Hi Yeeling,

 

Do you understand the significance of the "10" ?

[FurFarmandFork]

Hi Ryan,

 

I am planning to do an accelerated study on my snack at 40 degree Celsius. But I believe in order to get the Q10 for my product, i shall conduct a few trials. In my case, I do not study my product at different temperature, thus I assume my Q10 is 2. Is it a valid method?

 

Thanks.

 

 

I've seen that generalization on various resources (assume 2 until otherwise). It's still not very science based and I would determine your acceration factor based on your observations and actually study it at different temperatures. If you have a warehouse just store some product there for an "ambient" trial compared to your 40C samples.

 

If there are any fats in your snack product I would assume oxidation would be the determining factor if it's shelf stable by Aw like most snacks.

[Ryan M.]

As others have stated you basically need to validate the accelerated shelf-life study against something.  Typically, you will use side by side samples where you have a control at the normal temperature the product will be held and distributed against several other samples at varying temperatures.  Lots and lots of samples for each temperature and the control are needed as you will check one or multiple samples regularly for any differences against the control.

 

The control will need to hold up to the expected shelf-life at the normal temperature of the product for storage and distribution.

 

If you have the capability then you need to try different temperatures to determine your Q10.  It can vary quite a bit depending on the make-up of the product.  The "2" rule applies for most "systems", but that doesn't account for everything.

 

1. Does your facility already have products with some type of "shelf-life" established?
2. Is this a new product or products?
3. Are you looking to establish some type of product development to realization protocol for new products to establish shelf-life?

Answering these questions can help us help you.  

 

Ryan

[Charles.C]

Hi Ryan,

 

As i understand, for an intended storage temperature (Y) + wishing to implement a typical Q10 factor, the choices for accelerating temperatures (Z) are restricted via the equation Z= Y + 10a where a = 1,2,3 etc. (It seems from Post 10 that the OP is utilising a high (tropical?) storage temperature).

 

Uses of atypical Z values implies a recalculation for Q("deltaT").

 

Based on the OP, I deduce that no prior knowledge of this product/analogs/shelf-life measurements exist. Yeeling ?

[Mtumzima]

Very informative indeed