21 replies to this topic

[QM_AUS]

Hello Fellow members, I hope someone can give some insight into this. A contract bottler fill carbonated herbal drink into glass bottles for us. Bottles are shrink sleeved to protect contents from light and are stored in air conditioned environment. Ingredients of the drink are herbal extracts e.g chamomile, lemon balm extract etc. (extracted using ethanol as a solvent), water, Magnesium citrate, liquid fruit flavor, cane sugar, citric acid and preservative (211). Somehow few of the bottles in every carton are changing colour from brown to cloudy/white color. There is no noticeable taste difference between contents of different coloured bottles ruling out microbial contamination...I am assuming so....samples have been sent out for testing. Testing for APC, yeast, mould, aerobic and anaerobic mesophilic spore count and e-coli. No added sugar version of same drink doesn't have any colour change issue and was run before sugar formula which means if machine cleaning was not performed properly resulting in micro growth I will have same issue with no added sugar version as this was bottled before sugar formula. I am lost on ideas what could be the reason behind this colour change. Any help is very much appreciated. Thanks

 

[pHruit]

Might be worth running some of the "bad" product through a fine filter paper, to see what comes out the other side and what is left on the filter - may help identify whether it's something that is trying to precipitate out of solution.

What is the water source used for the product?

Is it blended in one big tank prior to packing, such that you'd expect it to be homogeneous before filling?
Any agitation of the tank during filling, or potential for the recipe to settle slightly such that there could be variation between bottles at the start/end of the run?

Any analytical differences between the good/bad bottles - e.g. Brix, acidity, pH?

If you leave a "bad" bottle for a couple of days, is there any sign of sediment collecting at the base of the bottle, and/or a clearer supernatant layer forming at the top of the bottle?

 

It is possible to get some interesting reactions between ingredients that can cause things to precipitate, and they can be difficult to predict as slight variations in water chemistry and/or ingredients can be the difference between a lovely stable product and one that forms unusual solids, although it would be a bit surprising to see this only affect some of the bottles within a homogeneous batch. 

 

I wouldn't completely rule out micro at this stage, at least until you've got the results back.

How are the bottles filled, e.g. hot fill, in pack pasteurisation etc? Varying cleanliness of e.g. bottle caps is one thing that can cause micro variations within a single batch, particularly if there is no post-fill pasteurisation or similar treatment.

[QM_AUS]

Might be worth running some of the "bad" product through a fine filter paper, to see what comes out the other side and what is left on the filter - may help identify whether it's something that is trying to precipitate out of solution.

What is the water source used for the product?

Is it blended in one big tank prior to packing, such that you'd expect it to be homogeneous before filling?
Any agitation of the tank during filling, or potential for the recipe to settle slightly such that there could be variation between bottles at the start/end of the run?

Any analytical differences between the good/bad bottles - e.g. Brix, acidity, pH?

If you leave a "bad" bottle for a couple of days, is there any sign of sediment collecting at the base of the bottle, and/or a clearer supernatant layer forming at the top of the bottle?

 

It is possible to get some interesting reactions between ingredients that can cause things to precipitate, and they can be difficult to predict as slight variations in water chemistry and/or ingredients can be the difference between a lovely stable product and one that forms unusual solids, although it would be a bit surprising to see this only affect some of the bottles within a homogeneous batch. 

 

I wouldn't completely rule out micro at this stage, at least until you've got the results back.

How are the bottles filled, e.g. hot fill, in pack pasteurisation etc? Varying cleanliness of e.g. bottle caps is one thing that can cause micro variations within a single batch, particularly if there is no post-fill pasteurisation or similar treatment.

Hi pHruit,

 

Thanks for your valuable feedback. Please refer to following

 

Might be worth running some of the "bad" product through a fine filter paper, to see what comes out the other side and what is left on the filter - may help identify whether it's something that is trying to precipitate out of solution.

 

Ran both good and discolored bottle contents through filter paper, nothing on the filter paper. All ingredients are 100% water soluble.

 

What is the water source used for the product?

 

Filtered water.

 

Is it blended in one big tank prior to packing, such that you'd expect it to be homogeneous before filling?

 

Yes,tank has stirrer to ensure homogenous mixing throughout the run

 

 

Any analytical differences between the good/bad bottles - e.g. Brix, acidity, pH?

 

pH of good bottle 4.7

pH of discolored bottle 4.3.... so not much difference.

 

 

It is possible to get some interesting reactions between ingredients that can cause things to precipitate, and they can be difficult to predict as slight variations in water chemistry and/or ingredients can be the difference between a lovely stable product and one that forms unusual solids, although it would be a bit surprising to see this only affect some of the bottles within a homogeneous batch. 

 

We ran no added sugar flavour before this batch and there is no issue with no added sugar batch. Only difference between this and no added sugar batch is the additional sugar otherwise rest all ingredients are same, can addition of sugar make liquid unstable.

Still don't get it why some bottles are good and others bad and that too in same box.

This is the pattern throughout the run which rules out that may be something happened at start, middle or end of the run.  

 

Many Regards

[pHruit]

Hmm, interesting!

 

Ran both good and discolored bottle contents through filter paper, nothing on the filter paper. All ingredients are 100% water soluble.

 

Ok, so this suggests that either nothing has precipitated out of solution, or if it has, it's too small to be caught by the filter paper. The cloudy appearance suggests to me that something is scattering the light, and is therefore probably in a solid rather than liquid phase. What grade filter paper did you use, and do you have any finer ones available?
Also note that, whilst the ingredients are nominally all water-soluble, the effect of combining them can do interesting things - for example, forming new compounds that are less soluble, or reducing the saturation point such that part of the content of something may cease to be soluble.

 

 

 

What is the water source used for the product?

 

Filtered water.

 

Is it blended in one big tank prior to packing, such that you'd expect it to be homogeneous before filling?

 

Yes,tank has stirrer to ensure homogenous mixing throughout the run

 

Filtered potable mains? What sort of filter? May be academic in this case, but can have a bearing in some circumstances, with certain weirder occasional issues with soft driks products.

 

 

 

 

Any analytical differences between the good/bad bottles - e.g. Brix, acidity, pH?

 

pH of good bottle 4.7

pH of discolored bottle 4.3.... so not much difference.

 

That looks like a fairly notable difference to me. Are you able to measure titratable acidity? The results imply that the acid content has increased, which makes me wonder about e.g. lactic/acetic acid production by bacteria.

When are the microbiological results due?

 

 

We ran no added sugar flavour before this batch and there is no issue with no added sugar batch. Only difference between this and no added sugar batch is the additional sugar otherwise rest all ingredients are same, can addition of sugar make liquid unstable.

Is the sugar just standard sucrose? If so, I wouldn't expect this to have this type of impact. With glucose you can occasionally see formation solid crystals if the glucose content is high, particularly if the product is subjected to repeated changes in temperature. Given what you've said about the drink, I wouldn't have thought this is likely here though.

 

 

Still don't get it why some bottles are good and others bad and that too in same box.

This is the pattern throughout the run which rules out that may be something happened at start, middle or end of the run.  

 

What is your filling setup? e.g. is this a multi-head filler?

I've seen issues where there is a subtle issue with one head in a multi-head unit, resulting in micro problems with a proportion of bottles spread throughout a batch. With some types of issue it can even be the case that not every bottle from the "bad" head is affected, making it even harder to spot the pattern and diagnose the actual issue.

Is there any post-fill processing, e.g. bath/tunnel pasteurisation?

[Ted S]

Good morning. The randomness of the problem is interesting. Are finished cases filled "sequentially" or randomly (by use of an accumulation table, etc...)? Hopefully you also sent good product out for testing as well as the bad. Did the production line suffer many stops/starts where random filled product could have sat open and exposed to the environment? Do you test the air quality in the production room for yeast, mold, etc...? The cloudy appearance with the sugared product could be a result of yeast = bad sanitation on one filler head as someone mentioned. The difference in pH is wide and somewhat of a concern, and as someone mentioned, could be lactic acid bacteria in the product. Was any old "rework" added back during production? Doing the titratable acidity is a very good idea as is refractive index (Brix). If the cloudy product is heated, does it clear up? 

[Ryan M.]

This is interesting and I'm genuinely perplexed because it doesn't seem to be microbiological related.  Subscribing in hopes to find out the root cause.

[QM_AUS]

Hi pHruit,

Thank you very much for sharing your knowledge.Please refer to following

 

 

Hmm, interesting!

 

Ok, so this suggests that either nothing has precipitated out of solution, or if it has, it's too small to be caught by the filter paper. The cloudy appearance suggests to me that something is scattering the light, and is therefore probably in a solid rather than liquid phase. What grade filter paper did you use, and do you have any finer ones available?
Also note that, whilst the ingredients are nominally all water-soluble, the effect of combining them can do interesting things - for example, forming new compounds that are less soluble, or reducing the saturation point such that part of the content of something may cease to be soluble.

 

Used grade 1.I will redo couple of bottles again to ensure my staff did in correct way.  

 

 

 

Filtered potable mains? What sort of filter? May be academic in this case, but can have a bearing in some circumstances, with certain weirder occasional issues with soft driks products.

 

I think it might be council water but I will check with our contract manufacturer.

 

 

 

That looks like a fairly notable difference to me. Are you able to measure titratable acidity? The results imply that the acid content has increased, which makes me wonder about e.g. lactic/acetic acid production by bacteria.

When are the microbiological results due?

 

Results are due late next week. Will keep you informed. Will ask lab to do titratable acidity in case micro results are high.

 

 

Is the sugar just standard sucrose? If so, I wouldn't expect this to have this type of impact. With glucose you can occasionally see formation solid crystals if the glucose content is high, particularly if the product is subjected to repeated changes in temperature. Given what you've said about the drink, I wouldn't have thought this is likely here though.

 

Cane sugar.

 

 

What is your filling setup? e.g. is this a multi-head filler?

I've seen issues where there is a subtle issue with one head in a multi-head unit, resulting in micro problems with a proportion of bottles spread throughout a batch. With some types of issue it can even be the case that not every bottle from the "bad" head is affected, making it even harder to spot the pattern and diagnose the actual issue.

Is there any post-fill processing, e.g. bath/tunnel pasteurisation?

 

I had same opinion as well but its contract manufactured and manufacturer said all heads were fine. In fact because No added sugar was done before this one and there is no issue with no added sugar which makes me think that if there was any issue with head/heads I would have issues with no added sugar bottles as well which is not the case.

[QM_AUS]

Good morning. The randomness of the problem is interesting. Are finished cases filled "sequentially" or randomly (by use of an accumulation table, etc...)? Hopefully you also sent good product out for testing as well as the bad. Did the production line suffer many stops/starts where random filled product could have sat open and exposed to the environment? Do you test the air quality in the production room for yeast, mold, etc...? The cloudy appearance with the sugared product could be a result of yeast = bad sanitation on one filler head as someone mentioned. The difference in pH is wide and somewhat of a concern, and as someone mentioned, could be lactic acid bacteria in the product. Was any old "rework" added back during production? Doing the titratable acidity is a very good idea as is refractive index (Brix). If the cloudy product is heated, does it clear up? 

Hi Ted S 

 

Finished cases are filled sequentially.

Yes,I sent a bottle each of good and bad.

I am informed that whole run just took 30 minutes with no start or stops.

Air testing- no they don't test. Will wait for lab results to see yeast count.

I have refractometer so will get on to Brix test and heat to check if it clears up.

 

Thanks for your input. 

[pHruit]

Well, I concur with Ryan M - "interesting".
I also usually feel a bit sorry for anyone dealing with an "interesting" problem, as whilst it is a curiosity for us external observers, it can be quite the headache for the poor QA manager trying to solve it...

Please update as test results etc become available, as we'd like to help but I think several of us are also genuinely very curious!

[QM_AUS]

Hello,

Received lab results. APC is very high in light(bad) sample. Noticeable difference in pH as well.

Please help in correlating results to issue.

 

Dark coloured(Good)                          Light coloured(Bad)                         

[QM_AUS]

Hello,

Received lab results.

APC is very high in light(bad) sample.

Same batch of raw materials used in both sugar(this is the one with issue) and no added sugar drink, only difference is sugar one contains added sugar which is sourced from cane sugar so I am thinking high APC can't be because of  RMs. If it is even because of sugar then also how come few bottles are good and others are bad  .

Can high APC relate to machine cleaning status but then I am wondering why no issue with no added sugar which was run before sugar on same machine within span of 30minutes.

Sorry I am asking question and then trying to answer it myself  but you all understand this is how puzzled I am with this issue.

Noticeable difference in pH as well.  

Please help in correlating results to the issue.

 

         Test                                           Dark coloured(Good)                          Light coloured(Bad)       

 

       Standard Plate Count                 <1 cfu/g                                                 250000 cfu/g

       E.coli                                           <0.3 MPN/g                                          <0.3MPN/g

       Mesophilic Aerobic Spore            <1 cfu/g                                                <1 cfu/g

       Mesophilic Anaerobic Spore        <1 cfu/g                                                <1 cfu/g

      Yeast                                             <10 cfu/g                                               <10 cfu/g

       Mould                                            <10 cfu/g                                               <10 cfu/g

      pH                                                     4.4                                                     4.8

 

Thanks.

[Charles.C]

Hi QM,

 

You only sent a total of 2 samples ?

[pHruit]

Hello,

Received lab results.

APC is very high in light(bad) sample.

Same batch of raw materials used in both sugar(this is the one with issue) and no added sugar drink, only difference is sugar one contains added sugar which is sourced from cane sugar so I am thinking high APC can't be because of  RMs. If it is even because of sugar then also how come few bottles are good and others are bad  .

Can high APC relate to machine cleaning status but then I am wondering why no issue with no added sugar which was run before sugar on same machine within span of 30minutes.

Sorry I am asking question and then trying to answer it myself  but you all understand this is how puzzled I am with this issue.

Noticeable difference in pH as well.  

Please help in correlating results to the issue.

 

         Test                                           Dark coloured(Good)                          Light coloured(Bad)       

 

       Standard Plate Count                 <1 cfu/g                                                 250000 cfu/g

       E.coli                                           <0.3 MPN/g                                          <0.3MPN/g

       Mesophilic Aerobic Spore            <1 cfu/g                                                <1 cfu/g

       Mesophilic Anaerobic Spore        <1 cfu/g                                                <1 cfu/g

      Yeast                                             <10 cfu/g                                               <10 cfu/g

       Mould                                            <10 cfu/g                                               <10 cfu/g

      pH                                                     4.4                                                     4.8

 

Thanks.

 

Can you clarify/confirm the pH - in your prior post, the "good" sample pH was higher than the "bad" one, whereas that now seems to be reversed?

What micro control is used during the process? Is the product pasteurised at some point? 

[Ryan M.]

Hmm...yes, what is your processing (heat or other treatment)?

 

However, I would pull more samples and do further testing.  To me...it seems it is related to the bottles or the caps.  Are there different bottles or different caps used between the product without sugar and product with sugar?

[QM_AUS]

Hi QM,

 

You only sent a total of 2 samples ?

 

Hi Charles,

 

I wanted to check before sending more samples if there was any micro issue.

Planning to send more samples.

Thanks

[QM_AUS]

Can you clarify/confirm the pH - in your prior post, the "good" sample pH was higher than the "bad" one, whereas that now seems to be reversed?

What micro control is used during the process? Is the product pasteurised at some point? 

You are spot on pHruit.

Prior post test results were using our portable pH meter(which I can see now is not very reliable) hence I sent samples to NATA accredited lab for testing.

pH results in my recent post are the ones I am relying on and using for investigation. I am planning to send more samples to ascertain these test results.

 

The product is not pasteurised at any stage.

 

 

The product is for one of our contract customer ,we supply all RMs apart from sugar and water and get it bottled through a big bottling company(I haven't audited bottler yet) who supplies to major supermarkets as well hence trusting their quality systems and relying on them regarding bottling stage QC/QA.

 

Thanks

[QM_AUS]

Hmm...yes, what is your processing (heat or other treatment)?

 

However, I would pull more samples and do further testing.  To me...it seems it is related to the bottles or the caps.  Are there different bottles or different caps used between the product without sugar and product with sugar?

Hi Ryan,

No heating or treatment. Simple process of mixing ingredients with filtered water in VATS with continuous stirring to ensure mix is even and nothing separates out.

Same type of bottles and caps used, stored in same storage area as well, goes through same processing stages...only difference is sleeves on the bottles to differentiate between sugar and No sugar formula. 

Thanks

[Karenconstable]

Hi all,

 

What an interesting mystery. 

 

I'm sure many others have already thought of this but I don't see it written in the thread....

 

If the spoilage is the result of microbial growth, then the difference between the no-sugar and sugar-containing products is (probably) because the no-sugar product doesn't allow the contaminant microbes to proliferate. 

 

So it's not that the non-sugar products aren't being contaminated (for example from a dirty filler head), but that the contamination can't grow to high levels in the non-sugar products, like it can in the sugar-containing products. 

 

Just my two cents!  Hope it helps. 

[pHruit]

Is this a short shelf-life chilled product?
Just trying to understand what the expected microbiological behaviour and shelf life is with "correct" product. There doesn't appear to be a process step to reduce microbiological loading, so is it the case that growth is expected to some extent, and shelf life is set accordingly, or is the preservative used in lieu of a kill step?

I'm never entirely comfortable relying on preservatives for this function, but also worth noting that benzoate alone may not have a sufficiently broad range of efficacy to cover a full range of potential organisms - hence often being used in conjunction with sorbate in soft drinks.

 

It might well be that whatever is growing is something that's somewhat ambivalent about benzoate, but nonetheless it's perhaps worth checking that the benzoic acid level is as expected.

 

Karenconstable's point about the differing nutrient profile between the with/without sugar products is very valid, and it could be the case that there is a process failure that in this case has led to microbiological contamination across both products, but with something that doesn't particularly want to grow without the availability of sugars. I'd be inclined to get some micro analysis done on the no sugar product too - you might find that there slightly elevated levels that are being kept in check by a lack of nutrients, in which case you can potentially reasonably conclude that the issue isn't just specific to the version with sugar added.

 

Ryan M's suggestion about caps/bottles is another good area for investigation. Are the bottles pre-formed or made on site? Is there a wash or decontamination stage for these and for the caps?

 

As for big, established packers - it doesn't mean that things won't go wrong, perhaps instead that when they go wrong it will be on a much larger scale

I've seen some quite surprising product issues from some very very large drinks packers, resulting from errant assumptions and/or complacency.

[Ryan M.]

Hi all,

 

What an interesting mystery. 

 

I'm sure many others have already thought of this but I don't see it written in the thread....

 

If the spoilage is the result of microbial growth, then the difference between the no-sugar and sugar-containing products is (probably) because the no-sugar product doesn't allow the contaminant microbes to proliferate. 

 

So it's not that the non-sugar products aren't being contaminated (for example from a dirty filler head), but that the contamination can't grow to high levels in the non-sugar products, like it can in the sugar-containing products. 

 

Just my two cents!  Hope it helps. 

 

Agree.  I had this thought as well.  Sugar in a product is a food source for microbes.  Of course at a certain point with added sugar you lower the water activity to help prevent microbial spoilage, but that's a lot of sugar.  

 

I would do more sampling and testing between the no sugar and sugar formulas with some stress of the samples prior to testing microbials.  I'm assuming your product is refrigerated / chilled. So, if I were you I would stress it at about 20oC for 24 hours to see what kind of microbial growth you get out of the products.  I would make sure you get samples on the sugar formula that show the color change and samples that do not show the color change.

 

Additionally, if you have the funds I would ask the lab to do microbial strain identification.  It can give you a good idea on the source of the microbes.

[QM_AUS]

Hello Everyone,

 

I also thought whether availability of sugar nutrition, dirty filler head, not thorough decontaminated bottle or lid has something to do with this colour change and  micro growth in only few bottles and not whole batch.

 

Product is considered to be shelf stable at ambient temperature hence both sugar and no sugar versions are stored at around 21 deg cent. environment

Bottles and caps are pre-formed and I am told by bottler that these goes through decontamination step.

 

As it is carbonated drink, in case there is any issue at carbonation stage or level of carbonation dropped suddenly, can this affect colour or stability of the product.

 

I will check what further testing can be carried out within lab budget.

 

Thanks everyone for your valuable inputs.

 

Have a nice weekend. 

[Ryan M.]

Just a thought here, the pH seems a bit on the high side for what is typically considered "shelf-stable" especially since the product does not undergo any type of "kill step".  Typically below 4.6 on the pH and you are OK.  This is something to look into because it can potentially be a food safety issue and also lead to quality issues.

 

 

 

Product is considered to be shelf stable at ambient temperature hence both sugar and no sugar versions are stored at around 21 deg cent. environment

 

Edited by Ryan M., 12 June 2021 - 12:58 PM.