Regarding “control”, this IMO is a highly complicated topic, both technically and commercially. Up until recent events, the main focus has presumably been on the Global Meat Industry. Perhaps becoming much less of a monopoly.
Initially discussions on Pathogenic E.coli-related incidents seem to have focussed on O157/meat sector which is product-OT to this thread but linked from a safety POV. Subsequently the scope has expanded (see USDA risk profile attached below) with respect to both serotypes of E.coli and food product categories, now including flour.
The following text uses this acronym -
STEC is a group of E. coli bacteria that produce Shiga toxin. A subset of STEC (ie "Pathogenic STEC") causes human illness.
A crucial element in appropriate controls has been the necessity to define the criteria for separating pathogenic and non-pathogenic STECs. The situation in 2010 for Non-O157 serotypes was summarised here -
Non-O157 Shiga toxin-producing Escherichia coli (STEC) strains have been linked to outbreaks and sporadic cases of illness worldwide.
Illnesses linked to STEC serotypes other than O157:H7 appear to be on the rise in the United States and worldwide, indicating that some of these organisms may be emerging pathogens. As more laboratories are testing for these organisms in clinical samples, more cases are uncovered. Some cases of non-O157 STEC illness appear to be as severe as cases associated with O157, although in general cases attributed to non-O157 are less severe.
There is much variation in virulence potential within STEC serotypes, and many may not be pathogenic. Of more than 400 serotypes isolated, fewer than 10 serotypes cause the majority of STEC-related human illnesses. Various virulence factors are involved in non-O157 STEC pathogenicity; the combined presence of both eae and stx genes has been associated with enhanced virulence.
A scientific definition of a pathogenic STEC has not yet been accepted.
Several laboratories have attempted to develop detection and identification methods, and although substantial progress has been made, a practical method of STEC detection has yet to be validated.
Worldwide, foods associated with non-O157 STEC illness include sausage, ice cream, milk, and lettuce, among others.
Results from several studies suggest that control measures for O157 may be effective for non-O157 STEC. More research is needed to uncover unique characteristics and resistances of non-O157 STEC strains if they exist. The public health significance of non-O157 STEC and the implications for industry practices and regulatory actions are discussed.
Afaik FSIS/USDA initiated controls on non-O157 STECs (Big 6) ca. 2012 using the combination criteria in above quote + certain O serogroups (Big 6). Their reasonings/background/protocols are detailed in the relevant F.R. Regulation (2012) and Risk profile (2012) which are attached below (for lab methodology see STEC2,3 at end this Post)
Fed.Reg. 2012 -Shiga Toxin-Producing Escherichia coli in Certain Raw Beef products.pdf 204.9KB
USDA Risk Profile for pathogenic Non O157 STEC,May 2012.pdf 1.02MB
For a little more context, here are a couple of articles (US-2012/Canadian-2015) explicitly/implicitly oriented to "control".
Consumer's Union - STEC-comments.pdf 32.91KB
Understanding non-O157 STEC associated with cattle and beef carcasses.pdf 2.61MB
("STEC" is here, i think, narrowly interpreted as per the 3 "pathogenic" criteria utilised by FSIS, ie stx/eae/O-serogroups rather than the more general definition of SHEC at top this post).
The rapid screening procedure currently available for “big 6” appears to be based on sweep PCR. Further confirmation of presumptive positives is required (see attachments at end. The procedure was described in one reference I saw as “challenging”.
The existence of non-O157 STECs in Canadian Meat Industry, potential significance, eg vis-à-vis USA, and related microbiological considerations seem to have been well - appreciated/documented by at least 2010. For example,
Regarding the flour events I noticed this criticism of the PHA’s progress pace, no idea whether representative of local opinion.
As you mentioned in previous post, the "O121" is effectively a serogroup potentially containing numerous serotypes (terminologies abound). The reason for the delay in specifying H values may be due to this factor but it's only speculation since hard data seems limited –
Isolates from the 2016 U.S. outbreak have been compared to the current outbreak in Canada by whole genome sequencing (via PulseNet International); the Canadian outbreak strain is not similar to the U.S. outbreak. Comparisons will continue to be made on an ongoing basis throughout the outbreak investigation in Canada.
The genetic pattern of the Canadian outbreak strain is unrelated to the strain of E. coli O121 that was responsible for an outbreak of more that 60 illnesses in the U.S. in 2016. That outbreak was traced to flour produced by a General Mills facility in Kansas City, MO.
STEC 1 - Isolation-Detection pathogenic E.coli in foods.pdf 700.39KB
STEC 2 - USDA,MLG 5B.05 - Detection-Isolation nonO157 STEC from Meat Products,2014.pdf 153.86KB
STEC 3 - validation commercial kits for detection E.coli O157,H7 and non-O157 STECS.pdf 141.33KB
STEC 4 - Isolation-Identification Pathogrnic E.coli in Food.pdf 442.22KB
STEC 5 - Australian Meat Technology - STEC update,2012.pdf 190.3KB
PS - Regarding general (consumer) mitigation in current scenario, can try -
Edited by Charles.C, 01 June 2017 - 04:18 AM.