Over 300 sickened in Norway: Beware the herbs as chives on scrambled eggs IDed as source

We investigated an outbreak of gastroenteritis following a Christmas buffet served on 4–9 December 2012 to ~1300 hotel guests. More than 300 people were reported ill in initial interviews with hotel guests.

chive.scrambled eggsTo identify possible sources of infection we conducted a cohort investigation through which we identified 214 probable cases. Illness was associated with consumption of scrambled eggs (odds ratio 9·07, 95% confidence interval 5·20–15·84). Imported chives added fresh to the scrambled eggs were the suspected source of the outbreak but were unavailable for testing.

Enterotoxigenic Escherichia coli (ETEC) infection was eventually confirmed in 40 hotel guests. This outbreak reinforces that ETEC should be considered in non-endemic countries when the clinical picture is consistent and common gastrointestinal pathogens are not found.

Following this outbreak, the Norwegian Food Safety Authority recommended that imported fresh herbs should be heat-treated before use in commercial kitchens.

 An outbreak of enterotoxigenic Escherichia coli (ETEC) infection in Norway, 2012: a reminder to consider uncommon pathogens in outbreaks involving imported products

Epidemiology and Infection / Volume 143 / Issue 03 / February 2015, pp 486-493

E. MacDonald, K.E. Møller, A.L. Wester, U.R. Dahle, N.O. Hermansen, P.A. Jenum, L. Thoresen and L. Vold


Lagos vs. Wisconsin: E. coli in dinking water and stools

Since early detection of pathogens and their virulence factors contribute to intervention and control strategies, we assessed the enteropathogens in diarrhea disease and investigated the link between toxigenic strains of Escherichia coli from stool and drinking-water sources; and determined the expression of toxin genes by antibiotic-resistant E. coli in Lagos, Nigeria. This was compared with isolates from diarrhoeal stool and water from Wisconsin, USA.

 lagos.waterThe new Luminex xTAG GPP (Gastroplex) technique and conventional real-time PCR were used to profile enteric pathogens and E. coli toxin gene isolates, respectively. Results showed the pathogen profile of stool and indicated a relationship between E. coli toxin genes in water and stool from Lagos which was absent in Wisconsin isolates.

The Gastroplex technique was efficient for multiple enteric pathogens and toxin gene detection. The co-existence of antibiotic resistance with enteroinvasive E. coli toxin genes suggests an additional prognostic burden on patients.

Preponderance of toxigenic Escherichia coli in stool pathogens correlates with toxin detection in accessible drinking-water sources

Epidemiology and Infection / Volume 143 / Issue 03 / February 2015, pp 494-504

H. Igbokwe, S. Bhattacharyya, S. Gradus, M. Khubbar, D. Grisowld, J. Navidad, C. Igwilo, D. Masson-Meyers and A.A. Azenabor


Public health concern? STEC in swine

This descriptive longitudinal study was conducted to investigate the fecal shedding of Shiga toxin-producing E. coli (STEC) in finishing swine and to characterize the swine STEC isolates that were recovered.

swine.stec.jan.15Three cohorts of finishing swine (n = 50/cohort; total 150 pigs) were included in the longitudinal study. Individual fecal samples were collected every 2 weeks (8 collections/pig) from the beginning (pig age 10 weeks) to the end (pig age 24 weeks) of the finishing period. STEC isolates were recovered in at least one sample from 65·3% (98/150) of the pigs, and the frequency distribution of first-time STEC detection during the finishing period resembled a point-source outbreak curve.

Nineteen O:H serotypes were identified among the STEC isolates. Most STEC isolates (n = 148) belonged to serotype O59:H21 and carried the stx2e gene. One O49:H21 STEC isolate carried the stx2e and eae genes. High prevalence rates of STEC during the finishing period were observed, and STEC isolates in various non-O157 serogroups were recovered. These data enhance understanding of swine STEC epidemiology, and future research is needed to confirm whether or not swine STEC are of public health concern.

Shiga toxin-producing E. coli (STEC) in swine: prevalence over the finishing period and characteristics of the STEC isolates

Epidemiology and Infection / Volume 143 / Issue 03 / February 2015, pp 505-514

M. Tseng, P.M. Fratamico, L.Bagi, D. Manzinger and J.A. Funk


Over 18.m pounds of products recalled in 2014 – USDA-FSIS

Almost 18.7m pounds of products were recalled last year, according to the U.S. Department of Agriculture’s Food Safety Inspection Service (USDA-FSIS).


Recall Summary for Calendar Year 2014

Total   Number of Recalls  94

Number of Pounds Recalled   18,675,102

                                         Recalls by Class (N=94)

Class   I           63        14,261,888

            II         23        3,817,387

            III        8          595,827

Recalls by Reason (N=94)

STEC*                                     5          1,840,533

            Listeria monocytogenes     7          270,926

            Salmonella                             4          372,414

            Undeclared Allergen           43        6,147,288

            Extraneous Material                        6          265,607

            Processing Defect                 4          59,203

            Undeclared Substance         2          80,084

            Other**                                  23        9,639,047

Recall by Species/Product (N=94)

Beef                22        13,232,176

            Mixed             14        2,151,495

            Pork               26        1,032,582

            Poultry***      31        2,230,901

            Ovine             1          27,948

* “STEC” includes recalls due to Shiga toxin-producing E. coli (STEC). STEC organisms include E. coli O157:H7, E. coli O26, E. coli O45, E. coli O103, E. coli O111, E. coli O121, and E. coli O145.
**”Other includes producing without inspection, failure to present for import inspection, and labeling issues, among others. 
***Poultry includes egg products.

Class I – A Class I recall involves a health hazard situation in which there is a reasonable probability that eating the food will cause health problems or death.

Class II – A Class II recall involves a potential health hazard situation in which there is a remote probability of adverse health consequences from eating the food.

Class III – A Class III recall involves a situation in which eating the food will not cause adverse health consequences.

A good idea? Ethiopian raw beef dish if you’re low on iron

When Ethiopians need an iron health boost, they don’t turn to supplements – they eat kitfo, a traditional dish that consists of marinated minced raw beef and is usually eaten with a sourdough-risen flatbread called injera, says Bebeta Asfaw.

kitfo.Ethiopian_foodMs Asfaw, who owns and operates Cafe Abyssinia in Mt Roskill, said kitfo was also somewhat like “a happy meal” in Ethiopia.

“It’s something we eat at every celebration and festival, from birthdays, weddings and many family events,” said Ms Asfaw.

She said the dish was considered to be healthy because both the beef and flatbread had a high iron content.

Lincoln Tan of The New Zealand Herald writes that teff, a valued iron-rich grain, is mixed with water and left to ferment for several days to make injera.

Ms Asfaw said injera was the staple bread for Ethiopians, much like roti is in India.

“We will always make our children eat kitfo because we think the beef is good for them and will make them strong and give lots of energy,” she said.

At her cafe, Ms Asfaw serves kitfo either completely raw or slightly cooked with injera on the side.

To eat kitfo, spoonfuls of raw beef can be placed into a piece of injera or you can use your fingers to tear off bits of the flatbread and dig into the beef.

Ms Asfaw said injera could also be replaced with standard sliced bread.



1kg topside beef (freshly cut)

6 teaspoons ground cayenne pepper (mitmita*)

4 tablespoons clarified butter (nitir kebe*)

1 teaspoon cardamom powder (korerima*)

salt and black pepper

* You will find these spices in Ethiopian or Indian shops/groceries


1. Cut the beef into small pieces and remove fat

2. Hand mince meat, marinate with mitmita and place the spicy ground meat in a dish

3. Melt the butter in a small pot on low heat, add the remaining mitmita, cardamom powder, (salt and black pepper to taste); remove from heat

4. Combine the spicy ground meat with the spicy butter; mix until completely marinated

5. Serve it immediately in a dish with injera or bread

A family of indoles regulate virulence and shiga toxin production in pathogenic E. coli

Enteropathogenic Escherichia coli (EPEC), enterohemorrhagic E. coli (EHEC) and enteroaggregative E. coli (EAEC) are intestinal pathogens that cause food and water-borne disease in humans.

indole.stec.jan.15Using biochemical methods and NMR-based comparative metabolomics in conjunction with the nematode Caenorhabditis elegans, we developed a bioassay to identify secreted small molecules produced by these pathogens.

We identified indole, indole-3-carboxaldehyde (ICA), and indole-3-acetic acid (IAA), as factors that only in combination are sufficient to kill C. elegans. Importantly, although lethal to C. elegans, these molecules downregulate several bacterial processes important for pathogenesis in mammals. These include motility, biofilm formation and production of Shiga toxins. Some pathogenic E. coli strains are known to contain a Locus of Enterocyte Effacement (LEE), which encodes virulence factors that cause “attaching and effacing” (A/E) lesions in mammals, including formation of actin pedestals.

We found that these indole derivatives also downregulate production of LEE virulence factors and inhibit pedestal formation on mammalian cells. Finally, upon oral administration, ICA inhibited virulence and promoted survival in a lethal mouse infection model. In summary, the C. elegans model in conjunction with metabolomics has facilitated identification of a family of indole derivatives that broadly regulate physiology in E. coli, and virulence in pathogenic strains. These molecules may enable development of new therapeutics that interfere with bacterial small-molecule signaling.

 PLOS ONE, DOI: 10.1371/journal.pone.0054456

Bettina Bommarius, Akwasi Anyanful, Yevgeniy Izrayelit, Shantanu Bhatt, Emily Cartwright, Wei Wang, Alyson I. Swimm, Guy M. Benian, Frank C. Schroeder, Daniel Kalman


E. coli in Igloolik not tied to drinking water: hamlet official

Hamlet officials in Igloolik, Nunavut, are still unclear as to the source of an E. coli outbreak that caused a number of residents to come down with severe diarrhea and vomiting.

igloolikhockey_screenHowever, it did not originate in the hamlet’s drinking water.

“From the testing which was done by our hamlet staff, it was confirmed it’s not coming from the drinking water,” said Celestino Uyarak, Igloolik’s assistant senior administrative officer.

One Igloolik resident is in Ottawa being treated for the illness, while several others have gone to the local health centre.

Nunavut’s health department has been investigating the source of the bacteria since mid-December. Over the holiday, health officials were on hand to observe how community feasts are conducted.

Uyarak said it is unclear when the source will be determined, but added that no new cases have been reported following the initial outbreak.

Raw milk risks: a science perspective from Europe

The European Food Safety Authority (EFSA) concludes that raw milk can carry harmful bacteria that can cause serious illness. Implementing current good hygiene practices at farms is essential to reduce raw milk contamination, while maintaining the cold chain is also important to prevent or slow the growth of bacteria in raw milk. However, these practices alone do not eliminate these risks. Boiling raw milk before consumption is the best way to kill many of the bacteria that can make people sick.

Spew milkConsumer interest in drinking raw milk has been growing in the European Union (EU) as many people believe it has health benefits. Under EU hygiene rules, Member States can prohibit or restrict the placing on the market of raw milk intended for human consumption. Sale of raw drinking milk through vending machines is permitted in some Member States, but consumers are usually instructed to boil the milk before consumption.

In their scientific opinion on public health risks associated with raw milk in the EU, experts from EFSA’s Panel on Biological Hazards (BIOHAZ) conclude that raw milk can be a source of harmful bacteria – mainly Campylobacter, Salmonella, and Shiga toxin-producing Escherichia coli (STEC).

The Panel could not quantify the public health risks associated with drinking raw milk in the EU due to data gaps. However, according to Member State data on food-borne disease outbreaks, between 2007 and 2013, 27 outbreaks were due to the consumption of raw milk.

Most of them – 21 – were caused by Campylobacter, one was caused by Salmonella, two by STEC and three by tick-borne encephalitis virus (TBEV).  A large majority of the outbreaks were due to raw cow’s milk, while a few of them originated from raw goat’s milk.

“There is a need for improved communication to consumers on the hazards and control measures associated with consumption of raw drinking milk,” says John Griffin, Chair of the BIOHAZ Panel.

Infants, children, pregnant women, old people and those with a weakened immune system have a higher risk of falling ill from drinking raw milk.  


Raw drinking milk (RDM) has a diverse microbial flora which can include pathogens transmissible to humans. The main microbiological hazards associated with RDM from cows, sheep and goats, horses and donkeys and camels were identified using a decision tree approach.

raw.milkThis considered evidence of milk-borne infection and the hazard being present in the European Union (EU), the impact of the hazard on human health and whether there was evidence for RDM as an important risk factor in the EU.

The main hazards were Campylobacter spp., Salmonella spp., shigatoxin-producing Escherichia coli (STEC), Brucella melitensis, Mycobacterium bovis and tick-borne encephalitis virus, and there are clear links between drinking raw milk and human illness associated with these hazards.

A quantitative microbiological risk assessment for these hazards could not be undertaken because country and EU-wide data are limited. Antimicrobial resistance has been reported in several EU countries in some of the main bacterial hazards isolated from raw milk or associated equipment and may be significant for public health. Sale of RDM through vending machines is permitted in some EU countries, although consumers purchasing such milk are usually instructed to boil the milk before consumption, which would eliminate microbiological risks. With respect to internet sales of RDM, there is a need for microbiological, temperature and storage time data to assess the impact of this distribution route. Intrinsic contamination of RDM with pathogens can arise from animals with systemic infection as well as from localised infections such as mastitis.

Raw-Milk-Card-FrontExtrinsic contamination can arise from faecal contamination and from the wider farm environment. It was not possible to rank control options as no single step could be identified which would significantly reduce risk relative to a baseline of expected good practice, although potential for an increase in risk was also noted. Improved risk communication to consumers is recommended.


Following a request from the European Food Safety Authority (EFSA), the EFSA Panel on Biological Hazards (BIOHAZ) was asked to deliver a scientific opinion on the public health risks related to the consumption of raw drinking milk (RDM). In particular, the BIOHAZ Panel was requested to identify the main microbiological hazards of public health significance that may occur in RDM from different animal species, to assess the public health risk arising from the consumption of RDM, to assess the likelihood of RDM being a significant source of antimicrobial resistant bacteria/resistance genes, to assess the additional risks associated with the sale of RDM through vending machines and via the internet and to identify and rank potential control options to reduce public health risks arising from consumption of RDM.

According to European Union (EU) legislation, “raw milk” is defined as milk produced by the secretion of the mammary gland of farmed animals that has not been heated to more than 40 °C or undergone any treatment that has an equivalent effect (Regulation (EC) No 853/2004). A top-down four-step decision tree was used to identify the main microbiological hazards associated with RDM of different milk-producing species in the EU. Microbiological hazards that can be transmitted to humans through milk and which were reported from cows, sheep and goats, horses and donkeys and camels in the EU were listed. Those hazards which could be transmitted via milk but were not reported from milk-producing animals in the EU were excluded from further consideration. Microbiological hazards identified as potentially transmissible through milk and present in the EU milk-producing animal population included the bacteria Campylobacter spp. (thermophilic), Salmonella spp., shigatoxin-producing Escherichia coli (STEC), Bacillus cereus, Brucella abortus, Brucella melitensis, Listeria monocytogenes, Mycobacterium bovis, Staphylococcus aureus, Yersinia enterocolitica, Yersinia pseudotuberculosis, Corynebacterium spp., Streptococcus suis subsp. zooepidemicus,the parasites Toxoplasma gondii and Cryptosporidium parvum and the virus tick-borne encephalitis virus (TBEV). Those hazards transmissible via milk of one species and present in the EU were also considered to be potentially transmissible by milk of other species if present in the EU.

napoleon milkEvidence for RDM as an important risk factor for human infection in the EU was based on epidemiological evidence that the hazard has been associated with illness from the consumption of RDM in the EU, the extent of occurrence of the hazard in different milk-producing species in the EU, the prevalence of the hazard in milk bulk tanks or retail RDM in the EU, and expert opinion. Between 2007 and 2012 there were 27 reported outbreaks in the EU involving RDM. Of these, 21 were attributed to Campylobacter spp., predominantly C. jejuni, one to Salmonella Typhimurium, two to STEC and three to TBEV. Four of the 27 outbreaks were due to raw milk from goats, the rest being attributed to raw milk from cows. The published literature was also considered, which highlighted additional outbreaks of TBEV and outbreaks of B. melitensis, M. bovis and STEC, although some of these were prior to 2007. No outbreaks attributable to L. monocytogenes in RDM were reported between 2007 and 2012.

STEC, Salmonella spp. and Campylobacter spp. are essentially ubiquitous pathogens and are likely to be found in milk-producing animals and their milk throughout the EU, as indicated by prevalence data from raw milk testing. TBEV was also considered to be a main hazard based on outbreak data, together with evidence of spread in Europe and the virus being detected in raw milk. B. melitensis and M. bovis have been associated with outbreaks involving raw milk, but these are less common and more geographically restricted than the other pathogens and control programmes in Europe have generally been successful in reducing human disease from these pathogens.

For other hazards, epidemiological evidence of illness was either historical or limited to reports from outside Europe. L. monocytogenes infection is associated with a high mortality rate in vulnerable groups, and the organism was as frequent as Campylobacter and STEC in raw milk. The lack of robust epidemiological data (including outbreaks) linking listeriosis to consumption of raw milk in Europe meant that it could not be considered a main hazard. The ability of L. monocytogenes to grow at chill temperatures, coupled with its prevalence in raw milk, suggests that further study in relation to RDM may be justified, particularly as several risk assessment models outside Europe have already been developed for this pathogen.

colbert.raw.milkThere is a clear link between drinking raw milk and human illness with Campylobacter spp., S. Typhimurium, STEC, TBEV, B. melitensis and M. bovis, with the potential for severe health consequences in some individual patients. Owing to the lack of epidemiological data, the burden of disease linked to the consumption of raw milk could not be assessed. Published quantitative microbiological risk assessment (QMRA) models from Australia, New Zealand, the USA and Italy, for Salmonella spp., Campylobacter spp., STEC O157 and L. monocytogenes in RDM from cows, were reviewed to identify their strengths and limitations. No QMRAs were available for RDM of other species. The risk estimates provided by the QMRA models reviewed cannot be extrapolated to the European situation as a whole. The outputs from the Australian and New Zealand risk assessments for STEC O157 and Salmonella spp. estimate a high level of milk contamination, which contrasts with the outputs from the risk assessment for these pathogens in RDM in one region of northern Italy, where the risk associated with STEC O157 was estimated as very low because of model uncertainty. Similarly, the Australian and New Zealand risk assessments predicted a higher risk for Campylobacter spp. than the risk assessment conducted in one region of northern Italy, largely as a result of differences in the extent of faecal contamination. From the model used in the Australian study it can be concluded that improving on-farm hygiene leads to a decrease in the number of predicted cases of illness due to Campylobacter spp., Salmonella spp. and STEC O157 from the consumption of RDM. A QMRA could have helped in further estimating the public health risks and evaluating the effect of the mitigation options in Europe for these hazards, but could not be undertaken because country and EU-wide data are limited.

Antimicrobial resistance has been reported in several EU countries in isolates of Campylobacter spp., Salmonella spp., STEC and S. aureus from raw milk or associated equipment such as milk filters, and may be significant for public health. Such isolates have been primarily associated with raw milk from bovine animals, which may reflect the more limited screening of milk from other species. Strains of Campylobacter spp., and particularly C. jejuni, exhibiting resistance predominantly to tetracyclines but also to some other antimicrobials have been reported in two Member States (MS). There have been no reports of antimicrobial resistance in isolates of Salmonella spp. from outbreaks associated with raw/unpasteurised in the EU in countries other than the UK. In the USA, there has been a report of a raw milk-associated outbreak caused by multidrug-resistant (MDR) S. Typhimurium, with a single fatality ascribed to resistance of the organism to antibiotics. Despite STEC O157 being the organism most commonly associated with RDM-related outbreaks of STEC gastrointestinal illness in several EU countries, little information is available about the occurrence of antimicrobial resistance in such outbreak strains. Antimicrobial resistance has been reported in a water buffalo raw milk-associated STEC O26 outbreak in one MS in 2008 and in raw milk-associated STEC outbreaks in the USA. Antimicrobial resistance in isolates of L. monocytogenes from raw milk and raw milk dairy products has only rarely been reported in EU countries.

Meticillin-resistant Staphylococcus aureus (MRSA) has not been isolated during outbreaks of infection associated with RDM in EU countries. Although not typically regarded as a food-borne pathogen, there have been increasing reports of the isolation of MRSA from dairy farms and bulk tank milk in several EU MS. Although identified in E. coli in bovine animals in some MS, extended spectrum beta lactamase (ESBL)/AmpC gene-carrying bacteria have not been reported in RDM in EU MS. In the USA, a range of Salmonella serovars with ESBL/AmpC genes have been identified in raw milk surveys.

Sale of RDM through vending machines is permitted in some EU MS, with considerable variation in the number of machines in different countries. There is little indication of RDM other than cow’s milk being sold through vending machines. Although vending machines dispense drinking milk in a raw state, consumers are usually instructed to boil the milk prior to consumption. If consumers were to comply with these instructions, the microbiological risks associated with raw milk would be eliminated. The temperature of RDM in vending machines is generally kept below 4 °C and therefore variability in milk temperature is more likely to arise between the farm and vending machine and between the vending machine and point of consumption by the consumer. One study in Italy demonstrated that temperature variability in the supply chain from farm to consumer could potentially result in the multiplication of L. monocytogenes, S. Typhimurium and STECO157:H7.

Fresh and frozen RDM of different species (cows, goats, sheep and camels) is available via internet sales although there are no data on the microbiological or temperature controls for these milks from the bulk milk tank through to the point of consumption. The variability in temperature control and duration of storage by consumers would contribute to the multiplication of some pathogens if these are present in the milk.

The steps in the production to consumption chain for RDM present many opportunities for contamination by microorganisms, some of which may be transmissible to humans. Intrinsic contamination of milk can arise from systemic infection in the milk-producing animal as well as from localised infections, such as mastitis. Extrinsic contamination of milk can arise from faecal contamination and from the wider farm environment associated with collection and storage of milk. Observance of good animal health and husbandry, together with the application of good agricultural practices (GAPs) and good hygienic practices (GHPs), are essential to minimise opportunities for contamination of RDM with pathogens in the production to consumption chain for RDM. No single step could be identified which would provide a significant reduction in risk relative to a baseline of expected good animal health and welfare and good agricultural and hygienic practices. Therefore, it was not possible to rank control options with respect to risk reduction since any deviations from the expected “best practice” baseline are likely to result in an increase in risk.

The reviewed QMRA models identified on-farm hygiene control and maintenance of the cold chain as factors influencing the outcome of the models for some pathogens. Although L. monocytogenes is not considered to be one of the main hazards associated with RDM in the EU, the reviewed QMRAs from outside the EU do show that the risk associated with L. monocytogenes in raw cow’s milk can be mitigated and reduced significantly if the cold chain is well controlled, the shelf-life of raw milk is limited to a few days and there is consumer compliance with these measures/controls.

The BIOHAZ Panel identified several recommendations arising from the opinion. There is a need for a better evidence base to inform future prioritisation and ranking approaches and studies should be undertaken to systematically collect data for source attribution for the hazards identified as associated with RDM and collect data to identify and rank emerging milk-borne hazards. Because of the diverse range of potential microbiological hazards associated with different milk-producing animals, hazard identification should be revisited regularly. There is a need for validated growth and survival models for pathogens in RDM of different milk-producing species, particularly in relation to the temperature and storage time of RDM from the producer up to the point of consumption. Finally, the Panel recommended that there should be improved risk communication to consumers, particularly susceptible/high risk populations, regarding the hazards and control methods associated with consumption of RDM.

STECs in Sweden on beef and leafy vegetables

This study investigated the occurrence of Shiga toxin-producing E. coli (STEC) in beef and leafy greens available on the Swedish market. New data are required for assessing the public health risk of STEC in food, which could be used for developing risk management strategies.

beef.stecFood samples were collected at retail stores, importers, outlets and the markets. Samples of minced or whole meat from cattle collected were fresh or frozen from 2010 to 2011. The beef sample collection included products from the most common countries or regions exporting beef to Sweden. The collection of leafy greens consisted of domestic and imported products that were available on the Swedish market from 2012 to 2013.

Detection of virulence genes (stx 1, stx 2, eae) and genes specific for different serogroups (O26, O103, O111, O145 and O157) was performed by real-time PCR followed by isolation of bacteria from the stx -positive enriched samples by use of immunomagnetic separation. STEC bacteria were overpriced isolated by an immunoblot thing method. All STEC isolated from the food samples were serotyped.

STEC was isolated from 23 (13 percent) of the 177 imported beef samples tested. Approximately 3 percent of the beef samples contained STEC on positive stx 2 and eae, both of which are important markers for the probability of the bacteria to  cause severe disease. In total, 27 STEC were isolated, belonging to 14 different serogroups. STEC O26 was most common (approximately 2 percent of the beef samples), whereas STEC O157, frequently implicated in STEC-related foodborne outbreaks in Sweden, was found in two (one percent) of the beef samples.

swedish-chefThe enrichment broth of 11 (approximately 2 percent) of the 630 samples from leafy greens were tested positive for stx 1 and / or stx 2 by PCR analysis; however, no bacteria were isolated. Presumptive STEC was detected in co-enriched samples from bothering domestic and imported products. E. coli was found in 68 (39 percent) out of 174 and 14 (30 percent) out of 46 samples of imported and English leafy greens, respectively, indicating that the proportion of stx -positive E. coli into the samples was low.

Quantifying antimicrobial-resistant E. coli and Salmonella enterica in beef production

Specific concerns have been raised that third-generation cephalosporin-resistant (3GCr) Escherichia coli, trimethoprim-sulfamethoxazole-resistant (COTr) E. coli, 3GCr Salmonella enterica, and nalidixic acid-resistant (NALr) S. enterica may be present in cattle production environments, persist through beef processing, and contaminate final products.

grass-fed.beefThe prevalences and concentrations of these organisms were determined in feces and hides (at feedlot and processing plant), pre-evisceration carcasses, and final carcasses from three lots of fed cattle (n = 184). The prevalences and concentrations were further determined for strip loins from 103 of the carcasses. 3GCr 

Salmonella was detected on 7.6% of hides during processing and was not detected on the final carcasses or strip loins. NALr S. enterica was detected on only one hide. 3GCr E. coli and COTr E. coli were detected on 100.0% of hides during processing. Concentrations of 3GCr E. coli and COTr E. coli on hides were correlated with pre-evisceration carcass contamination. 3GCr E. coli and COTr E. coli were each detected on only 0.5% of final carcasses and were not detected on strip loins. Five hundred and 42 isolates were screened for extraintestinal pathogenic E. coli (ExPEC) virulence-associated markers. Only two COTr E. coli isolates from hides were ExPEC, indicating that fed cattle products are not a significant source of ExPEC causing human urinary tract infections. The very low prevalences of these organisms on final carcasses and their absence on strip loins demonstrate that current sanitary dressing procedures and processing interventions are effective against antimicrobial-resistant bacteria.