45 replies to this topic

[Charles.C]

Dear Tony / GMO,

I wouldn't want to take the risk but I suspect that any E.coli would be killed if frozen. Maybe I would validate my theory.

Based on comments for food matrices and general microbiological obsrvations, a probability factor should perhaps be included but this statement seems rather optimistic to me. Have you seen any accessible validations ?

Eg for food

Bacteria can grow in the danger zone between 4°C and 60°C (40ºF to 140°F). Keep cold food cold at or below 4°C (40°F).
Refrigeration at or below 4°C (40°F) slows down most bacterial growth. Freezing at or below -18°C (0°F) can stop it completely. (But remember: refrigeration and freezing won't kill bacteria. Only proper cooking will do that!)

http://www.inspection.gc.ca/english/fssa/concen/cause/ecolie.shtml

although –

i second the idea that freezing does not kill beasties. i also work in a lab, and not only do we freeze E. coli at -80 degrees celsius (-112 F) for later use, we also freeze yeast. one kind of yeast, S. cerevisiae, is what is used in bread and beer. you definitely encounter it, but it is non-pathogenic. another kind, Candida albicans, is the variety that causes yeast infections. it is part of a woman's usual flora, but shifting the balance down there leads to bad things. wash your clothes!
posted by al24lola on February 23rd 2010 at 4:59pm

al24lola: note, though, that when you freeze lab coli or yeast you have to resuspend it in a ~25% v/v or greater glycerol solution, otherwise you get pretty terrible viability (i.e., a lot of them die... which means that freezing should actually have the desired effect here).

http://www.re-nest.c...me-hacks-109266 (!! )

Rgds / Charles.C

[Mike Green]

Dear Tony / GMO,



Based on comments for food matrices and general microbiological obsrvations, a probability factor should perhaps be included but this statement seems rather optimistic to me. Have you seen any accessible validations ?

Eg for food

http://www.inspectio...se/ecolie.shtml

although –



http://www.re-nest.c...me-hacks-109266 (!! )

Rgds / Charles.C

I think there is enough research out there to confirm that freezing(or freeze/thawing) does kill e-coli- I think the issue is that it doesn't kill 'em all -and if you consider that as few as 10 viable e-coli bacteria can cause illness(compared to the billion or so salmonella required to make us ill) I wouldn't personally be happy with freezing as a control

Regards

Mike

[MQA]

Hi SZY,

It does sound like your business is playing Russian roulette with this very high risk. The business is allowing raw meat product to potentially fall onto ready to eat products. That simply doesn't make sense. We were all taught years ago that raw foods should be placed beneath cooked foods in the fridge (both covered of course!). With what you have said, you are allowing these raw foods to be placed above ready to eats (so to speak).

I don't know your business: I don't have access to your floor map or know what type of meat production occurs. Suggestions: usage of plastic aprons that cover the entire body, fresh disposable gloves (after intense hand washing with food grade soap and sanitiser), and a hands-free hand washing basin between the two rooms. But this also takes time. And although the risks of cross contamination is reduced, the risk still exists.

What are your microbiological reports like? Conduct environmental swabs. Swab the employees during a change from one room to the other. Validate the risk levels. Show proof to your employer was it's bad decision making mixing raw and ready to eat.

You have to think food safety first. Consider the consequence of a cross-contamination. Think recalls. Think how damaging this would be to the reputation of the business. Always consider worse-case scenarios because they do exist every day in someone's food business.

I hope this was helpful for you.

Good luck with your decision making.

[Charles.C]

Dear Mike,

compared to the billion or so salmonella required to make us ill)

Debatable? I can remember there are (inferred) validations for incidents < 10 in the literature and you can see "1" quoted alongside E.coli O157 in various refs (although I agree that much higher numbers do occur in some other links, one FAO risk analysis document comes to mind), but I think that the conservative level is more popular these days.

From memory, the potency may also significantly depend on the species / strain as would be expected i guess (plenty to choose from!).

Rgds / Charles.C

added - one recent summary -

 infective doses.pdf   533.02KB   10 downloads

[Mike Green]

Dear Mike,



Debatable? I can remember there are (inferred) validations for incidents < 10 in the literature and you can see "1" quoted alongside E.coli O157 in various refs (although I agree that much higher numbers do occur in some other links, one FAO risk analysis document comes to mind), but I think that the conservative level is more popular these days.

From memory, the potency may also significantly depend on the species / strain as would be expected i guess (plenty to choose from!).

Rgds / Charles.C

Hi Charles- sorry- you are correct of course, I withdraw the 'billions' quote- which i just flippantly plucked out of the air to make a contrast-

as you correctly state it depends on the virulence of the strain and of course the state of the immune system of the 'victim' !

But I would still be thinking hundreds of thousands or millions at least?I have not seen any research to suggest that it is as low as 10 (or<10) for salmonella though-so I would appreciate any links you can provide for this- I love this forum- I learn new stuff every day!!

Regards

mike

[Charles.C]

Dear mike,

I added a link to previous post.
yr comment clearly also not impossible in some circumstances. There must hv been a lot of debates over this range already. (i can remember posting the details of the "chocolate balls" incident here a long time back.)
i also noticed the famous bad bug book (2009) gives (without details) "as few as 15-20 depending ..."

Rgds / Charles.C

[Mike Green]

Dear mike,

I added a link to previous post.
yr comment clearly also not impossible in some circumstances. There must hv been a lot of debates over this range already. (i can remember posting the details of the "chocolate balls" incident here a long time back.)
i also noticed the famous bad bug book (2009) gives (without details) "as few as 15-20 depending ..."

Rgds / Charles.C

Sorry didn't see that- very interesting doc-thanks

Mike

[Inesa]

Dear guys,

it stands in the book of Modern Food Microbiology (7th Ed, 2005)-->Chapter 26- Foodborne Gastroenteritis Caused by Salmonella and Shigella-->The Salmonella Food-Poisoning Syndrome (p. 625):

"Numbers of cells on the order of 10⁷-10⁹/g are generally necessary for salmonellosis. That outbreaks may occur in which relatively low numbers of cells are found has been noted¹⁸. From three outbreaks , the numbers of cells found were as low as 100/100g (S. Eastbourne in chocolate) to 15,000/g (S.Cubana in a carmine dye solution). In general, minimum numbers for gastroenteritis range between 10⁵ and 10⁶/g for S.Bareilly and S.Newport to 10⁹-10¹⁰ for S.Pullorum. "

Charles thanks for "infective doses", good to have it

[Tony-C]

I think Mike and Charles have got side tracked by my comment although some of the info is interesting.

Freezing does kill bacteria including Enterobacteriaceae contrary to what the CFIA has to say.

I wouldn't want to take the risk but I suspect that any E.coli would be killed if frozen

Regards,

Tony

[Mike Green]

I think Mike and Charles have got side tracked by my comment although some of the info is interesting.

Freezing does kill bacteria including Enterobacteriaceae contrary to what the CFIA has to say.



Regards,

Tony

Sorry yes getting a bit carried away there!- the concern expressed in my previous post is still there for me though- I have no doubt that some(even most) e-coli are killed by freezing-and even more by freeze /thaw cycling-but are enough killed (given the low infective dose) to declare it safe?

for example here is a link to research(from 2000) that found that viable ecoli were recovered from frozen beef after 12 weeks at -18 degrees c e.coli surviival

Regards

Mike

[GMO]

As others have quoted <10cfug-1 is sufficient dose for Salmonellae in chocolate. I believe it was Cadbury's downfall to believe <10cfu was safe...

[Charles.C]

Dear GMO,

In view of the thread title, I think the "aspect" is more on-topic than off. Not that I'm biased or anything.

This bit is perhaps more but hopefully still interesting.

I think the assessed logic discrepancy was never stated but one possible “semantic” problem can be illustrated by the interpretation of “acceptable = No Detection in 5x25g” as equivalent to: “acceptable level = < 0.008 cfu/g” on, perhaps, an average basis.

Such arguments inevitably fail for RTE goods due to the legally defined micro.requirement of “Nil detection” in a sample, ie there is simply no acceptable level of positive results. (unless you fudge “zero”). It would hv been interesting to see how C’s decisions were validated.

Similar difficulties IMO arise in ISO 22000’s precise requirement of a user stated “acceptable level” of a hazard. Maybe it is a waste of time trying to be clever/re-interpret/avoid the ISO simplicity, simply define/enter an appropriate legal “zero” and let the auditor do the worrying / give feedback.

Rgds / Charles.C

[GMO]

Such arguments inevitably fail for RTE goods due to the legally defined micro.requirement of “Nil detection” in a sample, ie there is simply no acceptable level of positive results. (unless you fudge “zero”). It would hv been interesting to see how C’s decisions were validated.

I don't think they were; that was the point!

http://www.timesonli...ticle682877.ece

[Tony-C]

I don't think they were; that was the point!

http://www.timesonli...ticle682877.ece

Thank for the link GMO.

Typical stuff from the bureaucracy. I would like to know if anybody thinks these sort of people contribute to food safety:

We think they made a mistake in assuming there was a safe level of salmonella in a product like chocolate. Our view is that there isn’t.

Think!

Level!

A Food Standards Agency spokesman today said the presence of salmonella in ready-to-eat foods such as chocolate was unacceptable at any level

So the presence of 1 Salmonella bacteria in 1,000,0000,000,0000.......tonnes of chocolate. Is unacceptable But 999 E.coli per gramme are okay in ready to eat fruit (Reg 2073)

Edited by Tony-C, 19 December 2010 - 02:02 AM.

[GMO]

Thank for the link GMO.

Typical stuff from the bureaucracy. I would like to know if anybody thinks these sort of people contribute to food safety:



Think!

Level!



So the presence of 1 Salmonella bacteria in 1,000,0000,000,0000.......tonnes of chocolate. Is unacceptable But 999 E.coli per gramme are okay in ready to eat fruit (Reg 2073)

Well the E.coli, hmm, not ideal! But it is well known in the confectionery industry that Salmonellosis can be caused by a very low number of bacteria; in the order of 1's to 10's cfu g^-1 rather than the millions normally associated with Salmonellosis. I remember looking back at some HACCP notes from my confectionery days when the Cadbury story broke and there was a slide which said:

THERE IS NO "SAFE" LEVEL OF SALMONELLA IN CHOCOLATE

I can't imagine our competitors genuinely weren't aware of that!

Not to say that Cadbury were isolated as IMO the confectionery industry is one of those really old food industries in the UK which hasn't moved with the times. Most of the staff have never worked in a high care or high risk facility and they had a laissez faire attitude to food safety which (I hope) has been challenged by this incident. After all, the only thing I really get annoyed about with Cadbury was their attitude once they found the Salmonella; they didn't communicate with the authorities, they weren't proactive and they didn't recall everything they should have IMO, even when the authorities found out but apart from that, the incident could have happened at any confectioner in the UK. (I only hope they would have handled it better once they realised.)



Does it annoy you that the consumers in the UK didn't seem to care about this though? Sure Cadbury's lost market share but not a lot. I remember seeing a mother buying Cadbury's buttons for her child at the time the story was breaking. I said something to her and she laughed at me! Had it not been such a UK "institution" it could have killed the company. I wonder what the reaction would have been now it's owned by a US company?

[Tony-C]

THERE IS NO "SAFE" LEVEL OF SALMONELLA IN CHOCOLATE

After all, the only thing I really get annoyed about with Cadbury was their attitude once they found the Salmonella; they didn't communicate with the authorities, they weren't proactive and they didn't recall everything they should have IMO, even when the authorities found out

I guess that rather than investigate and remedy a contamination problem they decided to define an acceptable level of contamination. Which clearly was a "big mistake".

I have to agree on your 2nd point. Aware of a problem in January and no product withdrawn until June.

[Charles.C]

Dear All,

Getting further OT but -

Regarding Tony’s earlier comment, consider this extract –

In the first performance standard, FSIS is proposing to require that an establishment's process for producing a low-acid canned product that receives a thermal, or other sporicidal process, result in a probability of 10-9 or less that there are spores of C.botulinum in a container of the product that are capable of growing, assuming an initial load of 1000 spores per container. Alternatively, the establishment may achieve a 12log10 reduction of C. botulinum.

( http://www.fsis.usda...ler_Canning.pdf )

So 1 positive in a billion is acceptable by definition. Not sure if this proposition was eventually adopted or not. i guess yes. Note also the necessity for an initial assumption.

The 5D / 6D etc rules for cooked meats certainly are regulatorily accepted and similarly must contain an implicit probability logic, even if unstated.

But how about a corollary - What (publically) acceptable risk is associated with setting a specification on a product such that it allows a (lot) of food to be placed on the market when it has been sampled and shown to contain a potential killer, ie it represents the 1 (positive) time in xmillion on average. The answer is resoundingly “zero tolerance” and therefore “Not Detected in 25g” or muliples thereof is the standard!.
The contradiction is evident but (politically?) unshakeable. Sort of understandable if you shop at the intended destination also ?

Such theoretical ponderings were highly fashionable (8-10yrs back), particularly linked with the subject of explicitly nominating regulatory FSOs, ALOPs etc as replacements for microbiological criteria but this enthusiasm seems to have rather faded away in the food control industry. Yet they were welcomed for nuclear reactors (I think).!

Rgds / Charles.C

[clover]

Amongst many issues in that establishment I believe the main area of concern was a vacuum packer that was used for both raw and cooked meats that was situated in the raw meat area. Your comments still apply and I'm sure Prof P agrees too although in quite a few more words !

The dips are probably less vulnerable being possibly pH protected and frozen but I do agree this is textbook how not to.

Regards,

Tony

Hi Tony, 

 

I'm currently facing this problem (refer above highlighted in bold). Do you (or anyone reading this) have any idea how I could perhaps convince my superior and the management that this is not acceptable? I've highlighted this issue many times but to no avail. And since finance seems to be quite an issue here, I'm presuming that they're not willing to purchase a separate machine to pack raw meat. As this is the case, we have no choice but to ensure that the vacuum machine is properly sanitize between packing of raw and cooked meat. 

[Tony-C]

Hi Tony, 

 

I'm currently facing this problem (refer above highlighted in bold). Do you (or anyone reading this) have any idea how I could perhaps convince my superior and the management that this is not acceptable? I've highlighted this issue many times but to no avail. And since finance seems to be quite an issue here, I'm presuming that they're not willing to purchase a separate machine to pack raw meat. As this is the case, we have no choice but to ensure that the vacuum machine is properly sanitize between packing of raw and cooked meat. 

 

Hi Clover

 

Maybe this will help :

 

An outbreak of the Escherichia coli O157 bacterium occurred in South Wales in 2005. It was the largest outbreak of E. coli O157 in Wales and the second largest in the UK
The cause was a vacuum packing machine used to package both raw meat and cooked meat without being properly cleaned between batches resulting in cross-contamination.
 

Kind regards,

 

Tony

[clover]

Hi Clover

 

Maybe this will help :

 

An outbreak of the Escherichia coli O157 bacterium occurred in South Wales in 2005. It was the largest outbreak of E. coli O157 in Wales and the second largest in the UK
The cause was a vacuum packing machine used to package both raw meat and cooked meat without being properly cleaned between batches resulting in cross-contamination.
 

Kind regards,

 

Tony

Hi Tony, 

 

yes, hopefully. Otherwise, I'll just have to cross my fingers and hope to God that tragedy doesn't strike.

[jacq]

   

Hi Clover,

 

 

The FSA has issued revised guidance on the use of vac packers for both raw and RTE meats, ( although imho I feel that it's just asking to be abused)

 

http://multimedia.fo...on-guidance.pdf

 

 

The main points of the revision are:

"

• If businesses can demonstrate that cross-contamination can be managed by time and effective cleaning and disinfection, then they do not need to have separate areas for handling raw and ready-to-eat (RTE) foods.
• Provided that businesses can demonstrate the effective cleaning and disinfection of equipment such as mixers, weighing scales and temperature probes between uses, then the same equipment can be used for raw and RTE foods.
• The third major revision concerns the effective cleaning and disinfection of more complex equipment such as mincers, slicers and vacuum packers to enable the same equipment to be used for both RTE and raw foods. In this case the equipment would need to be completely dismantled to allow all surfaces to be thoroughly cleaned."