12 replies to this topic

[Andreia]

Hello

I was wondering your opinion on the following subject.
I have a client who owns a pizzeria. Now he began to join a new sauce on a pizza.
The sauce is raw egg with cream, this sauce is done early in the day and then stored in the refrigerator. The sauce is put on the pizza before baking.

As I was not sure if this was an explosive cocktail sauce or not, i took the sauce (raw) for analysis.

And the results were: aerobic microorganisms-> 10000000 cfu / gr
E. Coli <10
Coliform bacteria <10
Staphyl. <10

Do you think, that because of the excessive number of aerobic microorganisms, my client should not use this sauce?

The fact is that the sauce was analyzed in raw, and it will only be consumed in the pizza after baking.
However, results for the pathogens were all <10ufc/gr.

What do you think?

Best Regards

Andreia

[GMO]

I would test the cooked pizza. Also consider that the raw sauce may contain pathogens in future and other pathogens you've not tested for.

The high aerobic count isn't necessarily a problem IMO if it's going to be cooked. Depends what is "in" that aerobic count and also what temperature the pizza reaches (normally mind bogglingly high from experience).

Probably the best approach will be to test the sauce raw over the proposed shelf life. Repeat this several times with different batches. Make up some pizzas with the sauce and datalog them if possible, if not do temperature measurements immediately on removal. Test after cooking. I'd specifically include Salmonella and Listeria on the test suites for both before and after. The benefit is if you do find pathogens in the raw sauce at least you can see if your cooking process is effective! If you don't there is some good guidelines out there for the kind of temperatures you need to achieve to kill them off.

As for finished micro aerobic spec; it's tricky because if you are getting a very high, hot, dry pizza oven, I would still expect an excellent kill on the aerobic vegetative bacteria. It would be interesting to see what it was.

An egg based sauce on pizza sounds pretty minging though!

[Andreia]

Thanks for your quick reply GMO.

I included in my analysis the pathogen salmonella(sorry, i didn't tell you earlier) and the result was absence in 25 gr.

Best Regards

Andreia

[Charles.C]

Dear Andreia,

My first reaction would be to distrust the micro.analysis ! >10 million probably meant uncountable. + (presumably) undetected coliform, E.coli, St.aureus. So what's in it ?,( i am not an egg / pizza expert.) What result is typical for (uncontaminated)raw egg ? (Salmonella detection is usually legally acceptable for retail egg of course). As GMO states, the usual cook step will probably eliminate 99.999 % but even so ??

My second reaction would be to validate the process, ie open a cook book or something to see if any specific reason not to use yr mixture and typical cook procedure.

I hope you did not send only one sample ???

Rgds / Charles.C

[Tony-C]

The high aerobic count isn't necessarily a problem IMO if it's going to be cooked.

It depends on the organisms present, what if Bacillus cereus is present in large numbers (which can be present in cream and produces heat resistant toxins)?

Regards,

Tony

[GMO]

It depends on the organisms present, what if Bacillus cereus is present in large numbers (which can be present in cream and produces heat resistant toxins)?

Regards,

Tony

Not likely to be a problem if the sauce is refrigerated as toxin production can only occur above 10 degrees. More likely to be an issue in the bread dough.

[Jean]

Hi !

I do have the same opinion as GMO. If raw egg cream sauce is made on a daily basis, refrigerated, used on the pizza before being baked in a preheated stone oven of temp. approx. 200^oC , then probability for any microbial hazard is insignificant. Baking temperatures are very high approx. above 255^oC for 6 or more minutes. If all the ingredients including the pizza dough are stored at temperatues below 5^oC, then it will not be a problem. I would suggest to verify all the stages by microanalysis to justify. Toxin production will not be of much concern as long as there is no temperature abuse causing the vegetative cells to multiply to excessive numbers during which toxins are produced in the presence of favourable conditions.

Edited by Jean, 02 May 2010 - 05:56 AM.

[Charles.C]

Dear All,

Well, notwithstanding the various negative results, the APC result could be interpreted as meaning that temperature abuse has in fact occurred. As per Tony's comment, the B. cereus emetic toxin apparently survives 126degC for 90 min which is quite impressive IMO but 255degC looks pretty conclusive ?.

Of course, temperature abuse might equally have occurred at the analyst's location or elsewhere ?

Charles.C

[Tony-C]

Not likely to be a problem if the sauce is refrigerated as toxin production can only occur above 10 degrees. More likely to be an issue in the bread dough.

I have to disagree, I have seen studies that show even at 8 C toxin has been present when there are high plate counts.

The oven may be 200 degrees + but what temperature does the centre of the pizza get to?

Regards,

Tony

[GMO]

I have to disagree, I have seen studies that show even at 8 C toxin has been present when there are high plate counts.

The oven may be 200 degrees + but what temperature does the centre of the pizza get to?

Regards,

Tony

I am going from the CFA guidelines (Best practice guidelines for the production of chilled foods) p9. Not familiar with any studies showing that toxin can be produced at 8; can you post them?

Yep, I agree the temperature of the pizza is key which is why I suggest datalogging or at least end of cooking temperature measurement. As I said though B. cereus in the dough is more likely to be an issue as it's less likely to be refrigerated and the core of the pizza will be dough, whereas the sauce will be on the surface. Many pizza ovens though are 300 degrees plus.

[Jean]

The oven may be 200 degrees + but what temperature does the centre of the pizza get to?

I checked our pizza cooking temperatures, the core temperatures were 90^oC plus and the pizza oven temperature was 300^oC plus. The pizza dough after being mixed with yeast is kept at room temp. (22⁰C) for about 2 hours before being baked. The remaining portions are kept in the chiller for dinner and again will be kept at room temperature for 2 hours before being baked. The dough mixture is made on a daily basis in our operation.

As per our operation , where the dough is freshly made on a daily basis, I will not consider toxin production as a significant hazard. Adequate temperature controls are imperative to avoid spore formers to germinate, multiply to excess numbers and produce toxins.

[Andreia]

Hello,

Thank you all, for your replies.

What i'll do, for next time I go to this customer, is to take a sample of the pizza sauce on the pizza after baking.

So maybe i will have more conclusive results.

Thanks

Best Regards

Andreia

[poppysnoss]

Dear Andreia,

My first reaction would be to distrust the micro.analysis ! >10 million probably meant uncountable.


Rgds / Charles.C

I agree with Charles. For an aerobic colony count, you are allowed to count up to 300 colonies, per plate. Even if the sauce had been serial diluted to 10(-4), results could have been interpreted up to 3,000,000. The next dilution would take it to 30,000,000 so the sums don't add up.

I would rather doubt if the lab would have taken dilutions to this extent unless the expected the sauce to be hum-dinging.