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RTE Cooked Smoked Fish - Yeast & moulds?


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#1 DRFSM

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Posted 01 March 2018 - 08:19 AM

Good morning all,

 

I had a micro guy come in to give me some advice a month or so ago. he recommended that for shelf life i test using a suite of methods.

 

Now, at last day of shelf life everything was in spec (going by local official micro levels guide for RTE foods etc.)

 

Problem is i had 2 samples from same cook that had Yeast counts of 1300cf/g and 3000cfu/g 

 

The product is a ready to eat fish product in vap pack packaging. stored chilled etc (processed, brined, smoked, roasted, packed, stored)  with an aW <0.95 and a WPS>3.5% 

 

id like to know

a) are these yeast counts high/low?

b) what my limits should be?

c) if i should be testing for them at all?

 

i cant seem to get a straight answer from my lab which is another issue all together... i dont see anything specifically in the guides i have read which state its more of a quality issue and results can vary depending on product etc. so im a bit confused.....

 

if my understanding is correct, i believe the values would help understand the QUALITY of the product? which by the way smelt, tasted, looked fine assuming ACC were ok. if ACC were not ok then values of greater that 10 to power of 6 would be an issue?

 

i dont know please help people! stop me dancing on my head...set me straight...  :happydance:



#2 DRFSM

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Posted 01 March 2018 - 08:32 AM

 

Problem is i had 2 samples from same cook that had Yeast counts of 1300cf/g and 3000cfu/g 

 

 

Sorry i meant 13000 and 3000



#3 DRFSM

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Posted 06 March 2018 - 08:39 AM

Anyone able to help please? im hitting my head on desk trying to find out info, even tried calling another lab but advice apparently is not free LOL@ THAT!!!



#4 Scampi

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Posted 06 March 2018 - 03:25 PM

I am not terrible familiar with yeast, but I can add this......the only way you'll know if it's high or low is to repeat the testing a few times to get a benchmark of your facility. 

 

Perhaps this document will help?  I did not look through it myself.

https://www.fsai.ie/...logical_limits/

 

or maybe this article

https://aggie-hortic...iology-of-food/


Because we always have is never an appropriate response!


#5 FurFarmandFork

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Posted 06 March 2018 - 04:16 PM

a) are these yeast counts high/low?

Can't say, it depends on what YOUR product testing history looks like or what other industry standards are. If that's normal for your product/process then it isn't high, iff you normally see much lower numbers then it is high. It's a relative number.

 

b) what my limits should be?

If there isn't an industry publication providing guidance, then the limits are based on at what point yeast/mold growth causes sensory failures of the product. You have to correlate a limit with when you/customers consider the product unacceptable.

 

c) if i should be testing for them at all?

Advice isn't free and labs are for testing according to request, not evaluating product. They will rarely help you make management decisions based on results, that's not their job or liability burden. If you're testing on the advice of your "micro guy" then ideally he should help you interpret the results.


Austin Bouck
Owner/Consultant at Fur, Farm, and Fork.
Consulting for companies needing effective, lean food safety systems and solutions.

Subscribe to the blog at furfarmandfork.com for food safety research, insights, and analysis.

#6 Charles.C

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Posted 07 March 2018 - 10:30 AM

Hi DRFSM,

 

Yes, yeast is normally a quality factor, not a safety one. Mould also mostly Yes but there are exceptions.

 

I notice you mention "roasted".

Is the finished product hot or cold smoked fish (salmon?) ??.

If hot (ie fully cooked) I would expect the heat to readily eliminate yeast so yr data is IMO "peculiar".

 

If cold smoked it's presumably a different story.

I attach 4 files, sf 2-4 for salmon,sf1 for "3 other fish species".

Yr yeast data appears not particularly unusual for the salmon refs sf2-3 but high for sf1

The basic micro data (eg plate counts) of commercially distributed cold smoked salmon appears to be highly diverse - see file sf4.

 

Attached File  sf1 - smoked-fish-micro data during-storage-period.pdf   688.86KB   14 downloads

Attached File  sf2 - cold smoked salmon micro data for chilled storage.pdf   374.1KB   15 downloads

Attached File  sf3 - cold smoked salmon, quality micro indices.pdf   171.99KB   13 downloads

Attached File  sf4 - quality commercial cold smoked salmon.pdf   40.81KB   14 downloads


Kind Regards,

 

Charles.C


#7 Charles.C

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Posted 07 March 2018 - 11:52 AM

addendum

 

If it actually is fully cooked, what kind of result for plate count was obtained ?


Kind Regards,

 

Charles.C


#8 DRFSM

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Posted 09 March 2018 - 09:53 AM

Yes the product was fully cooked and packed in 2 formats one grease proof paper inside a cardboard box, and the other packing format is vac packed.

 

Vac pack TVC's were: Sample 1 @ +21 days

TVC 11200 Anaerobic

TVC 14400 Aerobic

Enteros <10

Presumptive Psudomonas <100

salmonella not detected

Listeria not detected

Listeria enumeration <20

E.Coli not detected

 

A Raw Salmon Sample take from intake tested after 5 days of storage tested as follows (also contacted supplier regarding these results as i would not expect them to be like this from them but could be wrong)

TVC >1000000 Anaerobic

TVC 65000 Aerobic

Enteros 9900

Presumptive Psudomonas >1000000

salmonella not detected

Listeria detected

Listeria enumeration <20

E.Coli not detected

Moulds <20

Yeasts 22800

 

 

Sample 2 sam days production a couple of batches / hrs later. +21 days

TVC <100 Anaerobic

TVC 2200 Aerobic

Enteros <10

Presumptive Psudomonas <100

salmonella not detected

Listeria not detected

Listeria enumeration <20

E.Coli not detected

Moulds <20

Yeasts 3000

Vibrio not detected



#9 Charles.C

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Posted 11 March 2018 - 10:32 AM

Hi DFRM,

 

Thanks for data.

 

Do you have target micro. specifications for finished product ? For raw material (frozen salmon fillet?) ?

 

I assume all the numbers are cfu/gram

I assume all the "<"s actually mean"not detected" by some appropriate counting method.

 

Re - Raw Sample

I'm not quite sure what you mean by "Raw Salmon Sample".

Do you mean raw Salmon steak/fillet as initially received ? received frozen/vac.pac ?? then held 5 days chilled?     

 

Unclear what 1M Presumptive Pseudomonas actually means ? Why not confirmed ?

And a similar, but more muted, comment for the yeast data. (How many days incubation ?)

And a maybe similar comment for the anaerobic TVC count (no direct experience).

 

Re cooked data -

I deduce +21 days means 21 days in chilled storage after production. Around 5degC ?

What level of core cooking temperature/time is involved ? Hopefully not low.

No experience anaerobic counts but, as per yr OP, I guess the 2 sets cooked data look plausible other than yeast counts.

Offhand, seems curious that 1M cfu/gram Pseudomonas readily disappeared on cooking.

 

Maybe, minimally, need to test another pair raw material samples.


Kind Regards,

 

Charles.C


#10 DRFSM

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Posted 12 March 2018 - 06:26 AM

Hi DFRM,

 

Thanks for data.

 

Do you have target micro. specifications for finished product ? For raw material (frozen salmon fillet?) ? YES i have a spec for raw salmon from all my suppliers, for example here is one set of micro limits for their salmon as delivered from their end.

Total Viable Count @ 300C <10000cfu/g   (Target) 50000cfu/g Limit

Enterobacteriaceae  <100fu/g (Target)  (Limit) 1000fu/g

Coliforms   <10cfu/g (Target)   100cfu/g (Limit)

Escherichia coli   <10cfu/g (ta4rget)      10cfu/g (Limit)

Pseudomonas   <100cfu/g (Target)   1000cfu/g(Limit) 

Salmonella   Not Detected/ 25g  T(Target) Detected/ 25g (Limit)

Listeria monocytogenes  Not Detected/25g(Not Detected)   Detected/ 25g (Limit)

Listeria spp Not Detected/25g (Target) Detected/25g (Limit)

Staphylococcus aureus <25cfu/g  (Target) 50cfu/g (Limit) 

 

I assume all the numbers are cfu/gram YES

I assume all the "<"s actually mean"not detected" by some appropriate counting method.YES - the lab is ukas acredited, im not a micro guy so cant explain why this is the case, i note sometimes on various labs i have used over the years that when they see something but isnt high enough to count properly they state < a figure. like for example i had one sample that stated that listeria was detected but the enumeration (which i understand to be more important) was < than 10cfu/g or more importantly <20cfu/g which i believe to be the ready to eat threshold legally in UK

 

Re - Raw Sample

I'm not quite sure what you mean by "Raw Salmon Sample". RAW sample means the the raw salmon material as received in a polystyrene box packed in ICE, then cut in to a portion or side (for the brine / cold smoke / roasting processes,)

Do you mean raw Salmon steak/fillet as initially received ? received frozen/vac.pac ?? then held 5 days chilled?     YES - the raw salmon comes with a pack date only, i never understood why this is the case but it is for salmon at least, and is the case for 3 of my suppliers who 2 of which hold BAP certification and other certifications such as BRC.The 5 days is what we apply to essentially Sushi Grade /sushimi grade salmon, i.e salmon that is FARMED and filleted /portioned and sold raw to be then used by the consumer in sushi / sushimi dishes.

 

Unclear what 1M Presumptive Pseudomonas actually means ? Why not confirmed All i know is the lab is ukas accredited and use a method coded as: ISO 13720:2010 This may mean something to you but not I....maybe i should ask the lab this question as i presume that like if a listeria was high they would confirm? as part of that ISO method? i dont know though just guessing.

And a similar, but more muted, comment for the yeast data. (How many days incubation ?) Yeast method is based on practical food microbiology 2003 section 6.17 Method 1, again may mean something to you but not I..

And a maybe similar comment for the anaerobic TVC count (no direct experience).

 

Re cooked data -

I deduce +21 days means 21 days in chilled storage after production. Around 5degC ? YES <3.4°c once the product is cooked and chilled it is packed and given a shelf life of +21 days in Vac Pack. (before you ask, clostridium bottulinuum controls are in place we ensure WPS >3.5% and Aw <0.95 in our brine process.)

What level of core cooking temperature/time is involved ? Hopefully not low. Correct the product undergoes progressive cooking from bottom of the kiln and end up at the top, at this point temperature is checked and once 72°c is achieved at the core of several samples it is cooked for a further TIMED 10 minutes before being removed. During initial resting period out of kiln it should also be noted the product takes around 40 minutes to drop below 72°C so its still cooking long after its brought out of kiln.. if that makes sense...

No experience anaerobic counts but, as per yr OP, I guess the 2 sets cooked data look plausible other than yeast counts.

Offhand, seems curious that 1M cfu/gram Pseudomonas readily disappeared on cooking. Again i dont understand the result of Pseudomonas as it makes nose sense to me why it was that high, lab error? possible although unlikely high in raw material to start with? possible (have asked for their latest micro results but may not include the actual batch supplied) in house hygiene? possible but never detected Pseudomonas on any food contact equipment. or site for that matter.

 

Maybe, minimally, need to test another pair raw material samples.( yes this is my plan anyways but wanted to understand if i needed to first coz yeast made no sense and now neither does the pseudomonas come to think of it, thanks for that Charles :helpplease:



#11 Charles.C

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Posted 12 March 2018 - 05:45 PM

Hi DRM,

 

Thks for spec/comments.

 

The iso13720/2010 method for Psedomonas spp. delivers a, by definition, "Presumptive" Pseudomonas spp. value, eg 

http://almerja.com/r...d=708&idm=40169

 

An example of Pseudomonas spp. evaluation et al for some raw salmon meat stored under aerobic chilled conditions is attached. The value increased significantly in 5 days chilled storage although ultimately did not exceed approx 1000cfu/gram.

 

Suggests more data required as per previous post.

 

Attached File  Microbial quality fresh salmon,2016.pdf   556.82KB   10 downloads

 

PS - The result for Presumptive Pseudomonas spp. is seemingly based on reliance on (a) the selective agar + (b) an oxidase test. I daresay this is the reason for the "Presumptive". Would be interesting to see a validation.

(The USFDA BAM confirmation procedure for Pseudomonas spp. (in Cosmetics) is considerably more detailed.)


Kind Regards,

 

Charles.C


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