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Cracking in Cheddar Cheese

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MrCage View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote MrCage Quote  Post ReplyReply Direct Link To This Post Topic: Cracking in Cheddar Cheese
    Posted: 23 Mar 2010 at 9:54pm
There is plenty of information on leuconstocs but it is old! I will post some in due course. You will find leuconstocs throughout your plant, surfaces, floors etc. They are present in milk-low nos. Most are fairly heat sensitive but if you have enough due to the log. effects of heat on microorganisms there is a probability of a low level of survival. In most cases so low not to be important. Special media are needed for isolation see the paper by Billie et al mentioned on the site. They can be hard to work with!

There are a few references to leuconstocs located at
http://www.dairyscience.info/reference/view.asp . Just type in leuconstoc.
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michael View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote michael Quote  Post ReplyReply Direct Link To This Post Posted: 23 Mar 2010 at 9:54pm
This is starting to look more and more like work I did some 15-20 years ago.

I should have said more earlier but hoped that you might pick up hints from
http://www.dairyscience.info/cheese-quality/67-causes-of-early-gas-production-in-cheddar-cheese.html . We isolated several leuconstocs that could cause gassy cheese e.g. Leuconostoc mesenteroides ssp. dextranicum. These organisms were very interesting, some would not grow on Rogosa agar. They were generally salt tolerant, grew well in 6 % salt, and were psychrotrophic growing at 5C.

I strongly advise you to test your starters for leuconstocs! I would not be surprised if you isolated them. However if present they may be in very low concentration and special techniques are required to isolate them. I developed an isolation agar containing NaCl and calcium lactate that prevented the growth of starter lactococci and enabled the leuconstocs to be counted as a very small % of the overall lactic population.

The effect of heat on microorganisms is interesting. Hence your D value quest may be useful. Note even if you have an organism that is apparently sensitive to pasteurisation temperatures and have enough of the organism the statistics suggest that there is a probability of some cells surviving, say 1 cell per some litres of milk. If that cell can grow during cheese making and during cheese storage then you can have a problem. This is a fascinating problem and one that I continue to be interested in!

Good luck!
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MrCage View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote MrCage Quote  Post ReplyReply Direct Link To This Post Posted: 23 Mar 2010 at 9:54pm
Good news/bad news....we have worked with our local university to find that Leuconostoc is present in our aged Cheddar.

We will work on isolating source, milk, starter, Post Past Contamination.

There seems to be less info in cyberspace on leuconostoc...can you recommend a good source of info. I assume that Leuconostoc should not survive a HTST but am having a hard time finding a D value for this bug.

Thanks for your suggestions and thoughts.
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michael View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote michael Quote  Post ReplyReply Direct Link To This Post Posted: 23 Mar 2010 at 9:53pm
1. Firstly I think you mean that your salt in moisture is 4.5 % or higher! 2 % salt/40% moisture - 5% s/m

If this is the case , ok.

2. Cheese pH is ok.

3. I define mellowing as the length of time that the milled curd is in contact with the salt prior to the curd being moulded and pressed. This is an area that is often neglected in modern cheesemaking. Mellowing time is one of the factors that influences consistency of salting, variation in moisture and salt levels in cheese blocks. Perhaps you would recheck the value you have given.

4. Curd appears to be moulded rapidly thus avoiding-ihappens n some systems-curd during being held at high temperatues during pressing-this supports growth of NSLAB.

5. Temperature at the centr of the blocks going into maturation is high and I would recommend that you pre chill to lower the temp to < 10 C, ideally 7C, to reduce the potential for the growth of NSLAB.

Comments on your micro results

How old was the cheese when it was sampled? How do you know your micro lab is reliable; do you ever use 'spiked' or control samples?

Regards
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MrCage View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote MrCage Quote  Post ReplyReply Direct Link To This Post Posted: 23 Mar 2010 at 9:53pm
Lets start at the beginning.

State your pasteurisation conditions (164F/16 seconds)

What is the pH of your cheese? (5.05 - 5.10 on average)

What is the % salt in moisture? (0.045 - 0. 0 4 some Smilehigher some lower but typical.

Mellowing time? (45 minutes from whey removal to salting)

Time b/w end of mellowing and moulding- hooping (approx 10 minutes)

How long between moulding/hooping and going into cold store (approx 10 minutes)

What is the temperature at the centre of the cheese as it goes into the cold store for maturation (78F)

When do you notice the cracks/slits-months? (not sure but asked the question of customer today. If present at 3 weeks I presume mechaincal; if not present at 3 weeks but present at 3 months I would presume microbial).

I will come back to the micro results later. Note my comments re difficulty in getting some of these gas producers to grow. Sampling and media issues.

Look forward to hearing more! (we also add adjunct cultures)
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michael View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote michael Quote  Post ReplyReply Direct Link To This Post Posted: 23 Mar 2010 at 9:53pm
Lets start at the beginning.

State your pasteurisation conditions

What is the pH of your cheese?

What is the % salt in moisture?

Mellowing time?

Time b/w end of mellowing and moulding- hooping

How long between moulding/hooping and going into cold store

What is the temperature at the centre of the cheese as it goes into the cold store for maturation

When do you notice the cracks/slits-months?

I will come back to the micro results later. Note my comments re difficulty in getting some of these gas producers to grow. Sampling and media issues.

Look forward to hearing more!
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MrCage View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote MrCage Quote  Post ReplyReply Direct Link To This Post Posted: 23 Mar 2010 at 9:52pm
Came up snake eyes as we tested for a non starter contaminent that caused cracking. Below is the testing conducted. Can you offer any additional thoughts on potential causes? Negative for NSLAB, CAF, Props, Coliform, ASF. Thanks in advance

Methods and Procedures:
Heterofermentative Lactobacilli
Sample tested at -1, -2, -3, and -4
MRS Durham tubes incubated at 37C for 72 hours

Other Citrate Fermenters:
Sample tested at -1, -2, and -3.
Citrate Broth Durham tubes incubated at 30C for 72 hours

Results/Conclusion:

There was no gas production in either the MRS broth or the Citrate broth. This would indicate there is something else causing the problems with the cheese.

2/22/08: Due to the lack of results, the sample will be plated for Y/M, aerobic spores and proprionic acid bacteria.

Methods and Procedures:
Yeast/Mold Plating:
PDA agar is prepared by adding 39 grams of PDA agar to 1L of distilled water. The solution is stirred and heated to boiling. Subsequently the solution is transferred to 100 ml bottles and autoclaved at 121°C for 15 minutes.

1.5 ml of 10% tartaric acid is added to each 100ml bottle of PDA agar

Sample plated at -1, -2, -3, and -4 (Pour plate)
Plates will be incubated at 22C for 5 days.

Aerobic Spore Formers
Sample heated to 80C for 5min.
Sample plated at -1, -2, -3, and -4 (pour plate)
SMA agar incubated aerobically at 35C for 72 hours

Proprionibacteria:
Sample plated at -1, -2, -3, and -4 (pour plate)
PROP agar incubated anaerobically at 30C for 72 hours.
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michael View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote michael Quote  Post ReplyReply Direct Link To This Post Posted: 23 Mar 2010 at 9:52pm
I and a number of colleagues spent some years working on problems like this one!

There is quite a lot of information on gas formation, the main cause of slits or cracks, in film wrapped Cheddar cheese at http://www.dairyscience.info/cheese-quality/67-causes-of-early-gas-production-in-cheddar-cheese.html
. This mainly concerns early gas production but much of the material also applies to cracks/slits at 6 months.

You should be able to identify the main controls from this article.
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MrCage View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote MrCage Quote  Post ReplyReply Direct Link To This Post Posted: 23 Mar 2010 at 9:52pm
I would like to gather thoughts on cracking in Cheddar Cheese. This Cheddar is produced in a sealed barrier bag. The cracking is noticed on product around 6 months. We are conducting NSLAB testing to better understand the non - starter population but would like opinion on possible causes of this defect. I see the comment that Urease producing ST can actually cause some gas production(new info for me). I am inquiring storage temperatures but at the moment do not know.



Specifically what other tests would others recommend to determine cause of the defect as well as prevention measures.

Thanks in advance.

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