Guidelines for Assessing Microbiological Safety of Ready-to-Eat Foods

Guidelines for Assessing the Microbiological Safety of Ready-to-Eat Foods

These guidelines for assessing the microbiological safety of ready-to-eat foods have been revised and written by a Health Protection Agency Working Group in the UK and were published in November 2009 (About 1MB download)

http://www.hpa.org.u...C/1259151921557

Dear Ken,

Very nice one !

I saw this post after I had added a few related comments in another thread -

http://www.ifsqn.com...showtopic=13936

Rgds / Charles.C

Dear Ken and Charles,
These are nice posts.

Regards,
Kamwenji

Charles

I thought I would put this in the documents section as well. After a while good reference materials get buried in the other sections of the forum so if you know of any others which would be useful here........

Dear Ken,

I take it you are referring to generalised microbiological data.

IMEX, it’s unfortunate that databases of international microbiological criteria, whether regulatory or guidelines, for ranges of common food types are rarely available on the net for free access.
The FAO used to maintain one (available on request) but this also now seems to hv disappeared either in total or from public view. The majority of countries certainly have them but IMEX they are mostly either not-on-line or, if so, require designated user (often official) groups / money. There are a few notable exceptions as per yr linked UK document.

Compilations certainly exist for individual product types in journals and book form but most of these are again not freely on-line. For example –
Food safety regulations applied to fish by major importing countries (English) In: FAO Fisheries Circular (FAO), no. 825 / FAO, Rome (Italy). Fishery Industries Div. , 1989 , 110 p
(Contains micro. data but no longer current, obviously)

Items like the above are not collectively calalogued in any free on-line location AFAIK.

Google books offers one rare access route to off-line content but even their material has a rather mysterious system of categorisation at times.

Nap books (viewable on-line and sometimes dwlable) are another occasionally valuable resource, eg
Scientific Criteria to Ensure Safe Food, Committee on the Review of the Use of Scientific Criteria and Performance Standards for Safe Food, National Research Council 2003
eg - http://books.nap.edu...i...90&page=320

As an example of some existing general databases on-line, –
http://riley.nal.usd...p;topic_id=1501

The FAO links are no longer useful as far as I could see. 2-3 of the others utilisise the UK limits as in the 2000 edition.

Other than (library hunting) specific country general regulatory data or specific product guidelines of relevant organisations / customers, my most frequently used general data source is this aged but, IMHO, extremely valuable set of recommended guidelines via the ICMSF (a wonderful series) -

micro._guidelines_various_foods.pdf   812.8KB   312 downloads

Hope I hv answered the right question.

Rgds / Charles.C

Charles

A comprehensive reply and useful references.

I was also thinking more generally where documents are often referred to in many parts of the forum and then gets forgotten about over time until a new person posts on the same subject.

Some people will recall that the information is somewhere on the forum so might be an idea to get some of these moved onto the documents exchange as they are remembered.

Dear Ken,

Some people will recall that the information is somewhere on the forum so might be an idea to get some of these moved onto the documents exchange as they are remembered.

Yes. You are right. Time and entropy allowing. Despite the nice subject categorisation system Simon has put together, valuable data sources, particularly older ones, tend to be scattered all over the place and under a myriad of titles. A typical forum situation IMEX. I do find one limitation of the Documents Exchange section is an inevitable lack of prioritisation, it can involve a lot of work to find any useful material. Maybe some further sub-classifications would help (or overload?). Personally, I find the search functions with the (+…+) filter and “show posts” function more directly useful but maybe that’s just me. If English language is a bottleneck, the Documents Exchange is perhaps more user-friendly. I suppose all this is partly why databases were invented.

Rgds / Charles.C

PS - I just remembered one more, quite useful, general microbiological thread here which Simon initiated, particularly with respect to zero tolerances and accuracy of micro.data –

http://www.ifsqn.com...?showtopic=4590

In the EU we also have the Regulation for Microbiological Criteria for Foodstuff.

I've attached the CPA guidelines, which are very good.

also uploaded to the document exchange.

Caz x


http://www.chilledfo...ance_Ed_1.2.pdf

Dear Caz,

Well remembered. I approve of EC sticking it's neck out to demarcate safety / process hygiene factors even though many people (countries?) might be critical on it's fixation to Salmonella-only in so many places. (Although the USA hv been doing this for imports of certain products for several decades !) I did think about an inclusion in my post then I noticed all the recurring Enterobacteriaceaes and got put off a bit.

also noticed this intriguing footnote -

From 1st January 2010, for minced meat and meat preparations made from poultry meat, Salmonella must not be detected in 25g from any of the 5 samples tested and from that date there is no longer a requirement to label with cooking instructions. Until that date, all minced meat and meat preparations must be clearly labelled by the manufacturer indicating the need for thorough cooking prior to consumption. The provision of cooking instructions sufficient to achieve thorough cooking satisfies this requirement.

I wonder why ? Hopefully based on (somebody's) risk assessment.

Rgds / Charles.C

Charles / Caz

Thanks for the references.

A cynic might say that it is a bit OTT to have to remind consumers to cook raw meat before eating it - it was a concept my grandmother fully understood and would have been deemed 'common sense'

On the other hand, raw minced meat is eaten in certain countries (e.g steak tartare - a raw ground beef) so it looks like we have to work on the principle that if pathogens are not there in the first place, they cannot be a problem even when a consumer undercooks the meat.

Meanwhile I'll continue to apply common sense in the kitchen..........

In the EU we also have the Regulation for Microbiological Criteria for Foodstuff.

I've attached the CPA guidelines, which are very good.

also uploaded to the document exchange.

Caz x


http://www.chilledfo...ance_Ed_1.2.pdf

Thanks for that Caz it does look useful.

Can anyone explain to me how maximum E.coli of 1,000/g is an acceptable standard in ready to eat fruit and vegetables?

Regards,

Tony

Dear Tony,

Can anyone explain to me how maximum E.coli of 1,000/g is an acceptable standard in ready to eat fruit and vegetables?

Déjà vu ?? it’s an interesting question.

I have done a little searching. So far, hv not located any specific numerical data used for all these mic. criteria. However the “thought’ processes, originators, related prior directives which supposedly acted as input to the 2073/2005 document are discussed in some detail in the preamble to the actual regulation 2073/2005. This info is excluded in Caz’s link, probably to avoid totally bewildering the routine user. I didn’t pursue the refs as yet – there are a lot. One important point is that the limits hv to be practically realistic, ie Codex type mic.criteria. The implication is that relevant data does exist somewhere in the EC vaults.

Nonetheless, other sources are more visible. Regarding fruit and vegetables, maybe hv a look at this for some claimed typical numbers behind the general thinking of limits.

http://www.foodscien.../fshbull21a.htm

Although the logic appears to be intuitional, can see a possible demand for max 1000/g. 100>1000 limits also appear in the my prev. attached microrgs in foods vol2.

As another food source - meat patties, some more numbers are here.

E.coli_beef_patties_.pdf   364.55KB   76 downloads

I personally found the E.coli data in above quite old ref. rather startling, no idea if things hv changed these days. Approx 45pct > 100/g. (added - maybe hv drastically changed after viewing the current beef data referenced below, a result of the O157 incidents perhaps ??)

A more detailed, though still qualitative, rationale is offered for similar E.coli limits in the first (1997) attachment of pair below part of ongoing USA/ fsis meat pathogen study where the raw data is for poultry. Unfortunately, I didn't see any then or now database values for poultry to interpret these limits.
[added - it certainly seems remarkable to compare the poultry limits above with the 2nd attachment (2007) database figures for E.coli / beef trimmings where ca.98 pct are less than 100/g and 84 pct < than 10/g. I'm ignorant as to whether the 1997 beef situation was considered similar to poultry, ie shows a massive drop in beef contamination thru the pathogen reduction project duration for the defined type of plants utilised (federally inspected) or what]
E.coli_poultry_processing.PDF   131.48KB   58 downloads
micro_database_ground_beef_usa___Baseline_Data_Domestic_Beef_Trimmings.pdf   135.64KB   56 downloads

The HPA guidelines text regarding the use of “process criteria’ seem very curt considering the overall significance generally ascribed to good hygiene. Perhaps this reflects the so far failure to pin down any direct correlations between “indicators” and food safety -

Criteria are also applied for bacteria that indicate possible poor hygiene and/or substandard practices. In some circumstances these guidelines may also be used to assess more fully the safety and quality of food taken from the producer’s premises.

The above comments do not yet directly answer yr query but hopefully point a direction, maybe even to a risk analysis, somewhere.

Rgds / Charles.C

ps - just for interest, the regulation 2073/2005 is -

2073___2005.pdf   450.23KB   100 downloads

(main body same as Caz's link but without the added interpretations and nice format)

thanks to all of you for the great document..

Dear Tony,

Déjà vu ?? it’s an interesting question.

Rgds / Charles.C

Thank you Charles

It is deja vu but I would still like to know if any of our members work with ready to eat fruit/vegetables and if they have any comments.

Kind regards,

Tony

Dear Tony,

Sorry for hijacking yr question so please consider this as a brief semi-bump.

The primary, overall, microbiological strategy of the 2073 regulation is stated (Europa website) to be derived from this document –

discussion_paper_micro.criteria.pdf   710.27KB   81 downloads

I suggest the “EC” official thinking (rightly or wrongly) regarding process criteria may be related to this extract from the above paper -

b) Criteria for processes (process hygiene criteria):

Current Community legislation includes criteria which can be interpreted as being criteria set for processes in that they are used to indicate hygiene during the manufacturing process. It is still deemed necessary to prescribe these kinds of criteria in Community legislation in order to ensure the same hygiene level is being applied in establishments throughout the Community and to promote the safety of the foodstuffs produced. A question can nevertheless be posed whether these criteria could in the future be set in the national or Community guides to good practice and guides to the application of HACCP referred to in the recast of food hygiene legislation. Food businesses are best placed to know the most suitable process criteria to indicate good hygiene in processes used in their operations.

The UK guidelines were “validated/verified” for organic RTE vegetables by their own sampling/database (2000) whose results seem quite impressive IMO -

RTE_vegetables_micro_criteria.pdf   209.01KB   83 downloads
(Don’t know if any subsequent surveys)

A codex standard exists for fruit/vegetables (2003) but no micro.data. A very large scale review is well underway (meeting report 2008) however the diversity of commodities / locations / methods seems to be a major problem for unification.

As you rightly say, it would be very helpful if a range of geographical opinion/input could be seen, particularly in view of all the raw vegetable related disasters of recent years. Anybody plllease plllease !

Rgds / Charles.C

Dear Tony,

Sorry for hijacking yr question so please consider this as a brief semi-bump.

A codex standard exists for fruit/vegetables (2003) but no micro.data. A very large scale review is well underway (meeting report 2008) however the diversity of commodities / locations / methods seems to be a major problem for unification.

As you rightly say, it would be very helpful if a range of geographical opinion/input could be seen, particularly in view of all the raw vegetable related disasters of recent years. Anybody plllease plllease !

Rgds / Charles.C

Thanks for the attachment Charles:

L. monocytogenes, Salmonella spp., Campylobacter spp. and Escherichia coli 0157 were not detected in any of the samples examined, indicating that overall agricultural, hygiene, harvesting and production practices were good.
E. coli was detected in 1.5% (48/3200) of ready-to-eat organic vegetable samples, and was present at 102 cfu/g or more in 0.3%

This is organic food which is supposedly harder to achieve micro standards with so does not explain the limits set in EU regs of < 1,000/g E.coli.

I am still puzzled. If someone died from O157 food poisoning would it be a due diligence defence if the level was < 1,000/g ?

Kind regards,

Tony

Dear All,

Some more database materials and an extended set of proposed micro.standards (e) (I hv individually noted E.coli results so as to maintain Tony's comment ) –

(a) A 13,000 sample survey of UK (Scottish) RTE foods (2008) with respect to microbiological quality, chemical contaminants and packaging / labelling defects. Highly detailed results given and beautiful graphics for cross-analysis.
The E.coli data for vegetables/ fruit look similar to my previously posted (organic) results.
One summarising quote -

Elevated levels of hygiene indicators and high aerobic colony counts were responsible for all but 10 of the microbiological sample failures in 2008 across all food categories. It should be noted that food products that contained hygiene indicator organisms in the absence of any other pathogens were not considered an immediate risk to consumer health.

I suspect this is a legally necessary statement in UK. An opinion regarding the level at which unsatisfactory indicator results might be interpreted with respect to food safety wud be interesting but probably not forthcoming.

Uk_food_surveillance_2008.pdf   1.06MB   56 downloads

(b) A second survey on fruit and vegetables only in W.Australia, numerical standards used similar to UK. The E.coli results looked quite similar to (a) and also the interpretation.

W.Australia_Micro.quality_of_Fruit___Veg.pdf   312.38KB   50 downloads

© Thirdly, as a contrast to (a,b), a survey of various RTE leafy vegetables in Turkey (2008).
E.coli data from 1700 – 275,000 cfu/g !. The Turkish Food Codex is stated as setting the maximum E.coli at 95MPN/g, ie similar to UK. The overall micro.data is interpreted as implying a public health risk for the worst cases. One quote -

Environmental hygiene, hygienic production (water, soil, manure, agricultural chemicals, biological control, applications at home, hygiene of workers), hand contact, transportation, cleaning, storage and sanitation are important in ensuring food safety.

One wonders if there are some national disagreements with the EC/2073 interpretative procedure.

micro_quality_leafy_vegetables.pdf   337.87KB   44 downloads

(d) Microbiological hazards in fresh leafy vegetables and herbs, WHO, 2008
Report of the results of a large scale investigation of titled subject including extensive literature review of health related incidents and detailed analysis / recommendations of requirements of the manufacturing chain including benefits of washing with disinfectants and maintaining low temperatures etc.

WHO_micro.hazards_fresh_leafy_vegetables_and_herbs.pdf   1.06MB   56 downloads

(e) Elaboration of a regional standard for microbiological levels in foods (2002)
This is an ongoing FAO project. Contains proposed micro.standards for a large range of product types. Didn’t see any later reports.
Interesting that E.coli limits for raw, presumably RTE, vegetables are separated from frozen items, the latter having a 10x higher tolerance presumably due to anticipated consumer heating.

fao_micro_stds__egypt____part1.pdf   162.95KB   35 downloads
fao_micro_stds__egypt____part2.pdf   97.62KB   31 downloads

(f) added just for reference – previous (2000) edition of UK, RTE microbiological criteria. Now superceded by Ken’s initial post.

UK_microbiological_guidelines__2000__RTE_foods.pdf   146.26KB   59 downloads

Rgds / Charles.C

Dear Tony,

Regarding yr query (and mine) in this thread and another parallel one, on the possible linkage between “generic” E.coli and E.coli O157 in minimally processed produce, the experts (eg FAO/WHO, US National Research Council Subcommittee on Microbiological Criteria) seem to hv concluded that in general it is invalid to attempt to predict the safety of food products based on levels of coliforms, fecal coliforms, Enterobacteriaceae or generic E.coli.
(Compendium of methods for microbiological examination of foods, 2001, Kornacki and Johnson)

This extract (last updated 2009) describes the situation –

The Use of Indicators and Surrogate Microorganisms for the Evaluation of Pathogens in Fresh and Fresh-Cut Produce

The use of coliforms or “generic” E. coli as indicators of possible enteric contamination in other systems such as potable water sometimes stimulates consideration of them for similar use in fresh produce. A number of recent publications continue to address
this issue. In a white paper on the significance of these microorganisms in fresh and minimally processed produce, NFPA (Anonymous 2000) stated that the absence of correlation between these microorganisms and pathogens on fresh produce makes testing for coliforms or generic E. coli an unreliable indicator for the presence of pathogens. In some cases with products stored at refrigerated temperatures, elevated numbers of coliforms or generic E. coli may be an indication of temperature abuse or long-term refrigerated storage; however, the quality of many refrigerated produce items will not tolerate temperature abuse and generic E. coli
rarely reaches high numbers at refrigeration temperatures. The white paper indicates that these elevated populations would be quality issues; however, temperature abuse with certain kinds of fresh or fresh-cut produce may also indicate a possible safety concern (see Chapter II). This white paper also cites a personal communication from Kvenberg (1999, cited in Anonymous 2000) stating that NACMCF considers the use of “fecal coliforms” (or “thermotolerant coliforms”) as an indicator of fecal contamination not appropriate for fresh produce. This is consistent with a statement by Nguyen-the and Carlin (2000) indicating that fecal coliforms had poor value as fecal indicators in fresh vegetables. This is in part based on the capability of commonly present Klebsiella spp. and Enterobacter spp. to grow under thermotolerant test conditions. NACMCF (1999) discussed extensively the limits of “fecal coliforms” as an indicator of fecal contamination and recommended E. coli or similar organisms as more appropriate. Brackett and Splittstoesser (2001) address briefly the interpretation limitations of coliform indicators in produce; however, neither ICMSF (1998) nor Lund and Snowdon (2000) addressed the concept of fecal indicators in fresh fruits. Recently, Kornacki and Johnson (2001) indicated that “numerous studies have determined that E. coli, coliforms, fecal coliforms and Enterobacteriaceae are unreliable when used as an index of pathogen contamination of foods.”

http://www.fda.gov/F...s/ucm091372.htm

It would seem that the EC experts also concurred with above opinions.

Nonetheless, the exact thinking which chose m/M as 100/1000 for a process criterion remains unclear. It does correlate as i mentioned previously with ICMCF Mics. in Foods vol2. And also, I believe, with the IFST frequently quoted document on microbiological criteria. It is probably equally possible to find levels 10x less if one wishes to look around a bit.

Rgds / Charles.C

Dear Tony,

In some cases with products stored at refrigerated temperatures, elevated numbers of coliforms or generic E. coli may be an indication of temperature abuse or long-term refrigerated storage; however, the quality of many refrigerated produce items will not tolerate temperature abuse and generic E. coli rarely reaches high numbers at refrigeration temperatures.

This is consistent with a statement by Nguyen-the and Carlin (2000) indicating that fecal coliforms had poor value as fecal indicators in fresh vegetables. This is in part based on the capability of commonly present Klebsiella spp. and Enterobacter spp. to grow under thermotolerant test conditions.

Nonetheless, the exact thinking which chose m/M as 100/1000 for a process criterion remains unclear. It does correlate as i mentioned previously with ICMCF Mics. in Foods vol2. And also, I believe, with the IFST frequently quoted document on microbiological criteria. It is probably equally possible to find levels 10x less if one wishes to look around a bit.

Rgds / Charles.C

Thanks for that article Charles, another gem

There are a few contradictions in there but I think it adds to the debate really. Why would you set E.coli numbers so high? especially with claims they are out competed by Enteros.

I think this sums the situation up:

The importance of selecting the significant target pathogen for the specific product, its source, handling practices, and distribution practices cannot be overemphasized. The same is true for selection of the indicator or surrogate to represent those pathogens. The extensive lists of considerations and procedures should be helpful when using indicators and surrogates with fresh and fresh-cut produce.

Kind regards,

Tony

Dear Charles and Tony C.,

(This is really an interesting topic with al lot of valuable attachments)

May I remind you that the EU directive 2073/2005, indicates e.coli both as an hygienic indicator and as a food safety criteria (live bivalve moluscs) The criteria for e. coli as a food safety criteria are n=1, c=0, M = 230 MPN/100g of flesh and intra-valvular liquid.
In precut vegetables e.coli is only an hygiene indicator. In other product is is specific mentioned that e.coli is an indicator for faecal contamination (e.g. meat). Unfortunately it is not motivated why e.coli was selected as hygiene indicator in this industry.
In the Netherlands the hygiene indicator for precut vegetables used to be lactobacillus. I think this was only local legislation, because I can not find anu EU documentation on this. Then again, I do not know why this bacteria was selected as a hygiene indicator.

Recently EFSA published an outbreak report for 2008. I have attached it. Only 75 Vtec outbreaks were reported (=1,3%). Compared to Salmonella: 1888 outbreaks and Campylobacter: 488.

Some information abstracted from the documents provided by Charles, regarding to E.coli O157:
(a) Scottish food surveillance.
Only 56 samples were analysed for e coli O157 from total of 9548 samples

(b) survey on fruit and vegetables only in W.Australia
In 497 tested samples E coli O157 was absent

(d) Microbiological hazards in fresh leafy vegetables and herbs, WHO, 2008.
According table 2.3 (annex 2) 11 e-coli outbreaks have been linked to vegetables, of which 9 in the USA and 2 in Sweden.

Dutch data: in 2007 1932 samples fresh cut RTE were analysed. No e.coli O157 was found.

It would be interesting to have some USA or Canada data on e.coli O157. Analysing the data, mentioned above, it looks like O157 is not a big issue on fruits and vegetables in Europe. I’m very curious about the cause of this difference.

Dear All,

The criteria for e. coli as a food safety criteria are n=1, c=0, M = 230 MPN/100g of flesh and intra-valvular liquid.

- wondering if the sample size of 1 is adequate?

In the Netherlands the hygiene indicator for precut vegetables used to be lactobacillus

- I am just as dumbfounded as you as to why this has been chosen as a hygiene indicator although I believe the situation in the USA on the outbreak of E. Coli O157 on fruits and vegetables appears to be rather unusual. I have to suspect the possibility of cross contamination (logistic or handling etc) rather than at farm source. I am merely speculating but perhaps the reason why Europe is not experiencing similar outbreak may be due to the different point to point supply chain management style.

Cheers
Charles Chew

It would be interesting to have some USA or Canada data on e.coli O157. Analysing the data, mentioned above, it looks like O157 is not a big issue on fruits and vegetables in Europe. I’m very curious about the cause of this difference.

Not surprisingly, a lot of other people both in EC and USA hv also noticed the apparent difference. There is already a substantial literature on this topic, some of which i posted in another thread here but sadly so far cannot re-locate it. From memory, the cultivation set-ups can be quite different, for example with respect to the official control requirements at the 'field' level.

Regarding E.coli -

The fundamental logic is that "generic" E.coli is not pathogenic (more precisely, most strains are not pathogenic). However in certain situations, it's presence/quantity has been shown to be applicable as an indicator for fecal contamination and thereby with enteric pathogens. Water sources are a (historically) prime example.

http://en.wikipedia....scherichia_coli
http://www.hc-sc.gc....ortance-eng.php

One non-harmless example of E.coli -

Traveler's diarrhea or traveller's diarrhoea, abbreviated to TD, is the most common illness affecting travelers. Traveler's diarrhea is defined as three or more unformed stools in 24 hours passed by a traveler, commonly accompanied by abdominal cramps, nausea, and bloating.[1] It does not imply a specific organism, but enterotoxigenic Escherichia coli is the most common.[2

http://en.wikipedia....eler's_diarrhea

Interesting to compare to, say, Salmonella where all strains (2500+) are seemingly considered pathogenic.

Rgds / Charles.C

The fundamental logic is that "generic" E.coli is not pathogenic (more precisely, most strains are not pathogenic). However in certain situations, it's presence/quantity has been shown to be applicable as an indicator for fecal contamination and thereby with enteric pathogens. Water sources are a (historically) prime example.
Rgds / Charles.C

Having acceptable levels of max 1,000/g for a hygiene indicator does not sound like a great idea to me. I usually test for generic hygiene indicators - Enteros and high counts(Maximum 100/g) are then followed up with pathogen tests.

Regards,

Tony

Dear Madam A. D-tor,

I managed to locate the older thread on E.coli O157 which does still make interesting reading IMO.

http://www.ifsqn.com...showtopic=13723


Rgds / Charles.C