12 replies to this topic

[Heffer03]

Hello!

I work in a meat proccessing plant, we produce cured sausages that are cooked and then vacuum packaged. In the last couple of months we have been receiving some complaints about spoilage product showing greenish discouloration. The green spots first begins at the surface of the sausage and then covers all the product including the inside part. No off-odors or off-flavors.

The thing is that we have not found what is causing this problem. So far we have tryed culture the product in the laboratory to find a high lactic acid bacteria count, but nothing seems to grow (using MRS agar, incubation temperature 30 ° C (86 F) for 3-5days).

We're in a dead end ...... have anyone had any experince with this kind of spoilage and how to deal with it? Should we tryed to culture under other conditions? How about chemical spoilage (not microbiological)?

I really appreciate any help

 

 

 

[Charles.C]

Hello!

I work in a meat proccessing plant, we produce cured sausages that are cooked and then vacuum packaged. In the last couple of months we have been receiving some complaints about spoilage product showing greenish discouloration. The green spots first begins at the surface of the sausage and then covers all the product including the inside part. No off-odors or off-flavors.

The thing is that we have not found what is causing this problem. So far we have tryed culture the product in the laboratory to find a high lactic acid bacteria count, but nothing seems to grow (using MRS agar, incubation temperature 30 ° C (86 F) for 3-5days).

We're in a dead end ...... have anyone had any experince with this kind of spoilage and how to deal with it? Should we tryed to culture under other conditions? How about chemical spoilage (not microbiological)?

I really appreciate any help

 

 

Hi Heffer,

 

Not my direct area of expertise but, as i daresay you know already, there are various hits in Google offering  explanations for such a phenomenon, eg

 

 green spotted meat.pdf   91.73KB   115 downloads

 green spotted sausages.pdf   73.2KB   125 downloads

 

I deduce that yr QA people were willing to taste the green material. Beyond the call of duty IMO.

 

PS - not sure about "sausage" but IIRC yr query has previously appeared several times here with respect to "meat". Maybe try a search for "green".

[Charles.C]

addendum

 

I tried searching for "green meat". Yielded -

 

http://www.ifsqn.com...-meat-greening/

http://www.ifsqn.com...red-dried-meat/

http://www.ifsqn.com...ing/#entry24212

 

and this (very old) one in error (via "meat”) but which offers quite good weekend reading (one or two in questionable taste) –

 

http://www.ifsqn.com...1-some-classic-tommy-cooper/

[Rener De Jesus]

If no bacteria are isolated, greening might be caused by H2O2 or H2S. It generally appears after an anaerobically stored product is exposed to air. There was a chemical reaction happened.

[Charles.C]

If no bacteria are isolated, greening might be caused by H2O2 or H2S. It generally appears after an anaerobically stored product is exposed to air. There was a chemical reaction happened.

 

As per the previous attachments.

[ronvalerio22]

Posibly Pseudomonas fluorescens bacteria

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[Charles.C]

Posibly Pseudomonas fluorescens bacteria

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Yes, possible -

 

 Spoiled meat Microbes.pdf   1.1MB   65 downloads

 

 green meat.png   155.36KB   3 downloads

 

Unfortunately reported experiences between observing green colour of vac-pack meat and detecting spoilage-type taste/smell seem to vary, ie (+)/(-)

[Derf]

Hi - If not solved already some things you may wish to look at:

 

May be curing reaction related. Suggest also checking cure (sodium nitrite?) levels.

From a microbial point of view how are your counts on the packed product? (should be able to achieve <100 CFU/g, higher = recontamination post cook)

What temperatures are you cooking to? Are they adequate? (say 72C internal)

How is the microbial quality of the meat and other materials going into the product? (high counts can cause greening later)

[qualityfishgirl11]

Are you using a MAP gas flush process when you pack? Maybe the gases used are not in the correct ratio?

[qualityfishgirl11]

This is from the FAO corporate document repository.  Are the vacuum packages losing the seal? Have you changed the packaging material and changed the permeability of the film? It could be that more oxygen is entering the packages. Check into your process for changes if this is a new development.  If you are using gas flush- maybe you are not flushing out enough oxygen from the pack or the film is allowing too much in? Did you change suppliers? New employees? 

Take a look at the packaging process- are the sausages dry? If there is water in the packs- this could be an issue.

Have you been testing for anaerobic bacteria or just aerobic? If the seal is ok, and oxygen is removed it would make sense you cant find any aerobic bacteria.  Without more information, it is hard to be more helpful- but these are some ideas I had

 

This is from the FAO corporate document repository. 

Barrier against gases

Good barrier properties against oxygen and evaporation are the most important features in order to ensure:

a) Exclusion of oxygen

Air contains about 20 percent oxygen. Oxygen negatively affects unpackaged meat and meat products during prolonged storage periods. It changes the red meat colour to grey or green and causes oxidation and rancidity of fats resulting in an undesirable off-flavour.

[Heffer03]

Are you using a MAP gas flush process when you pack? Maybe the gases used are not in the correct ratio?

 

Hello,

 

No we're not using MAP gas flush process.

 

 

 

This is from the FAO corporate document repository.  Are the vacuum packages losing the seal? Have you changed the packaging material and changed the permeability of the film? It could be that more oxygen is entering the packages. Check into your process for changes if this is a new development.  If you are using gas flush- maybe you are not flushing out enough oxygen from the pack or the film is allowing too much in? Did you change suppliers? New employees? 

Take a look at the packaging process- are the sausages dry? If there is water in the packs- this could be an issue.

Have you been testing for anaerobic bacteria or just aerobic? If the seal is ok, and oxygen is removed it would make sense you cant find any aerobic bacteria.  Without more information, it is hard to be more helpful- but these are some ideas I had

 

This is from the FAO corporate document repository. 

Barrier against gases

Good barrier properties against oxygen and evaporation are the most important features in order to ensure:

a) Exclusion of oxygen

Air contains about 20 percent oxygen. Oxygen negatively affects unpackaged meat and meat products during prolonged storage periods. It changes the red meat colour to grey or green and causes oxidation and rancidity of fats resulting in an undesirable off-flavour.

 

 

The seal from the affected batchs seems ok, no lost of vacuum. No new packaging supplier, no major changes has been made in the packaging process.

The only batches that appear to be affected are the ones from the low cost sausage formula... Just reading all the info share by Charles.C and what Derf posted about material quality of meat. It seems logic that high counts from the raw materials are the cause.

 

But since we can't isolate the bacteria from the green product, would it make sense to try to isolate Pseudomonas or lactic bacteria from the raw materials? How to connect one with the other? Or just by finding high count in the raw material it could be imply that it's the root cause? High counts above log 6, right?

[Derf]

Hi - Believe you are trying to overthink this with "type" of bacteria. If you are getting low counts with both standard plate count and MRS on the finished product chances are the issue is raw material related or formulation related.

 

Keep in mind if this is a cured (with sodium nitrite) sausage the "pink" colour is a reversible reaction some of which is "green". (see the attachments from Charles)

 

With "low cost" keep in mind that this can't be from "low quality". It is technically harder to make a good "low cost" sausage than it is to make a good "high cost" sausage.   (good technical people can make a silk purse from a sows ear!)

 

Check total counts on all raw materials

Make sure the meat is not "old" and even though fine microbially it is not rancid.

Check total counts of the emulsion prior to filling into casing. (cooking is not a fix all)

Check correct formulation - adequate cure to make it pink and adequate antioxidant to keep it that way.   (its it a premix - has the supplier done something wrong)

And, only just thought of this, is the product utilising natural (gut) or synthetic (cellulose/collagen) casing? Seen some really bad natural gut casings. (high counts/dodgy materials to wash/lower counts)

 

High counts above log 6 for raw meat would be unacceptable.  (anything under log 5 is pretty good and achievable in my experience)

[Hassan2017]

Good morning Guys,

 

Well, as i read your description of the problem you mentioned couple of things 

 

- Its on the surface of the sausage.

- Spot like then reach the inner aspect of the product.

- Its cooked & vacuumed.

 

Before jumping to any conclusions:

 

- Define the product's raw materials -  Go through & review your Hazard analysis & CCP's - cleaning & sanitation process - go through your production steps - verification & validation processes.

- Each Raw materials should be tested ( packaging - spices - meat - fat - etc ... ) against the region meat suspected Bacteria including the guys mentioned.

 

- Include the Casing raw material ( do you use animal origin or Collagen Casing! is it tested , approved supplier , preserved correctly etc ... ! 

 

- include the meat type ( is it fresh - vacuumed *with or without Gas* ) ( chilled or frozen ) ( origin of the meat - slaughtering-house - supplier shipping process - etc .. )

 

- review & verify that all your raw material's suppliers are not the source of the contamination.

 

- review & verify that the cooking procedure is sufficient *time & temperature* .. review the packing stag - storage stage

 

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I was working as Food Safety Manager for a hypermarket and i faced this problem once in vacuum meat and i found that the root cause was Pseudomonas spp. :

 

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Mainly the Greening  Spoilage in vacuum packaged meats caused by microbial production H₂O₂ or H₂S.  H₂O₂ production in meat has been associated with several types of lactic acid bacteria (primarily Lactobacillus)

 

Considering the Meat Pigments

           

The oxidant (H₂O₂) reacts with nitrosohemochrome (cured meat color cmpd) to form a green porphyrin compound.

 

H₂S greening occurs in fresh meats that have been vacuum packaged and stored between 1-5^oC.

H₂S reacts with myoglobin  to form sulphmyoglobin in meats with a pH above 6.0.

H₂S is produced by:

• Shewanella putrefaciens and Pseudomonas spp. (when O₂- permeable films are used).
• Some lactobacilli (when O₂- impermeable films are used).