viernes, 31 de enero de 2014

Bacterial indoor contamination

Location and indoor microbiome contamination are strongly linked, ¿are these factors taken into account by the food industry?

Buildings are complex ecosystems that house trillions of microorganisms interacting with each other, with humans and with their environment. Understanding the ecological and evolutionary processes that determine the diversity and composition of the built environment microbiome—the community of microorganisms that live indoors—is important for understanding the relationship between building design, biodiversity and human health.
In this study, we used high-throughput sequencing of the bacterial 16S rRNA gene to quantify relationships between building attributes and airborne bacterial communities at a health-care facility. Airborne bacterial community structure were quantified and environmental conditions in patient rooms exposed to mechanical or window ventilation and in outdoor air.

The phylogenetic diversity of airborne bacterial communities was lower indoors than outdoors, and mechanically ventilated rooms contained less diverse microbial communities than did window-ventilated rooms. Bacterial communities in indoor environments contained many taxa that are absent or rare outdoors, including taxa closely related to potential human pathogens.

Building attributes, specifically the source of ventilation air, airflow rates, relative humidity and temperature, were correlated with the diversity and composition of indoor bacterial communities. The relative abundance of bacteria closely related to human pathogens was higher indoors than outdoors, and higher in rooms with lower airflow rates and lower relative humidity.

The observed relationship between building design and airborne bacterial diversity suggests that we can manage indoor environments, altering through building design and operation the community of microbial species that potentially colonize the human microbiome during our time indoors.

The information generated by this study is very important for food producers and processors, especially for those engaged with massive products such as meats and highly processed fooods.

Source: The ISME Journal (2012) 6, 1469–1479; doi:10.1038/ismej.2011.211; published online 26 January 2012

miércoles, 29 de enero de 2014

Salmonella Biofilms Extremely Resistant to Disinfectants

Disinfectants are not able to kill after 7 days growth of Salmonella 

Researchers at the National University of Ireland, Galway, have discovered that common disinfectants face an uphill battle killing Salmonella once it has had the time to form a biofilm – a community of cells that attach to each other and a surface, increasing the density of bacterial growth and providing support from harsh environments. Allowed Salmonella enterica cells to grow for seven days before applying three types of disinfectant:  sodium hypochlorite, sodium hydroxide and benzalkonium chloride.
They found that none of the disinfectants was able to kill the cells after that amount of time. Even soaking the biofilms in disinfectant for an hour and a half failed to kill them.
Once Salmonella cells are allowed to become established on a surface, the number of cells will increase over time, resulting in difficulty  if not impossible  to completely eliminate or kill all cells once part of a mature biofilm.
The strains she tested were able to form a biofilm on glass, steel, polycarbonate plastic, glazed tile and concrete.
In terms of ‘real world’ environments, it is estimated that most organisms are capable of this, and that a high percentage of micro-organisms will form a biofilm to optimize growth and survival.
To head off an issue of resistance,  recommended appropriate and frequent cleaning to prevent the buildup of bacteria on surfaces and improving handling practices such as ensuring raw food is prepared in a separate area from cooked food to reduce the risk of cross-contamination.


Clostridium perfringens toxin could trigger multiple sclerosis (MS)

C. perfringens is commonly found on raw meat and poultry

Epsilon toxin produced by some strains of Clostridium perfringens can cause MS-like damage in the brain. MS is is generated by genetic and environmental factors but the exact environmental trigger is not known yet.
Pathogen effect The US Centers for Disease Control and Prevention (CDC) estimates that non-epsilon toxin producing C. perfringens strains cause nearly a million cases of foodborne illness each year. C. perfringens is commonly found on raw meat and poultry and some strains produce a toxin in the intestine that causes intestinal illnesses.

Multiple sclerosis is an inflammatory disease of the central nervous system characterized by blood brain barrier (BBB) permeability and demyelination, a process in which the insulating myelin sheaths of neurons are damaged.
This study provide evidence that supports epsilon toxin's ability to cause BBB permeability and show that epsilon toxin destroy the brain's myelin producing cells, oligodendrocytes; the same cells affected in MS lesions.

Type B strain found. Linden and her colleagues discovered C. perfringens type B (a strain that was not known to infect humans) in a  21-year-old woman experiencing a flare-up of her MS, in a study published in October last year (see below). Researchers tested samples of local foods for the presence of C. perfringens and the toxin gene. Of the 37 food samples, 13.5% were positive for bacteria and 2.7% were positive for the epsilon toxin gene.

Epsilon toxin. C. perfringens types B and D carry a gene (epsilon toxin) that emits a pro-toxin (a non-active precursor form of the toxin) which is turned into the epsilon toxin within intestines of grazing animals. The epsilon toxin travels through the blood to the brain, where it damages brain blood vessels and myelin, the insulation protecting neurons, resulting in MS-like symptoms in the animals. While the D subtype has only been found in two people, based on prior studies by other investigators, the B subtype had never been found in humans.
“This bacterium produces a toxin that we normally think humans never encounter. That we identified this bacterium in a human is important enough, but the fact that it is present in MS patients is truly significant because the toxin targets the exact tissues damaged during the acute MS disease process.
A high intake of dietary salt has been linked to amplifying and triggering autoimmune responses that can lead to MS, while high levels of Vitamin D may be associated with a lower risk of MS progression.

jueves, 23 de enero de 2014

Chilean Blueberries Get Extra Scrutiny at U.S. Ports of Entry

APHIS has ordered enhanced inspections at the ports of entry

USDA’s Animal & Plant Health Inspection Service has erected new barriers to the entry of Chilean blueberries to the United States.

Neither fears about last year’s Cyclosporiasis parasite in fresh produce nor Hepatitis A in berry blends had anything to do with the APHIS action. Instead, it’s the European grapevine moth and its cousins that the agency is trying to keep out of the country.
And, since the insects might ride in on blueberries from Chile, APHIS has ordered enhanced inspections at the ports of entry for berries currently in transit and fumigation for shipments that are still in the fields. Fumigations to eliminate the insects are expected to occur in Chile prior to export as the service is not currently available at U.S. entry ports.

European grape moths, vine moths and grape berry moths are invasive species found in Chile. They are also found in Europe, Asia and northern Africa.

The insects were listed as exotic organisms of high invasive risk by APHIS in 2008 and are subject to quarantine in the U.S. They’ve been intercepted at U.S. ports of entry 20 times since 1984. The pest is a threat to 27 different types of plants, including grapes, berries, cherries, currants, lilacs, nectarines and plums.

The moths are not a direct threat to human health or food safety.


The latest on Listeria: Five foods most likely to be contaminated

Five foods that can become contaminated and how to use them safely

1. Canned and raw seafood.
When the FDA conducted a safety test of many types of food for Listeria, the type that tested highest might come as a surprise to most people given the lack of press: smoked seafood. Of the 7,855 samples tested, 12.9 percent contained listeria. Preserved fish also tested high, as did raw seafood. Knowing this, I can tell you I’ll only be buying my smoked salmon and canned smoked oysters from reputable companies, and I’ll be throwing salmon into pasta and other dishes rather than eating it cold on bagels. 
2. Fruits of all kinds
Cantaloupes can pick up the Listeria bacteria, as can other melons, but so can any fruit that’s sprayed or washed with water containing listeria picked up from the soil. According to an FDA risk assessment for Listeria, more than 11 percent of all fruits sampled tested positive for listeria. But here’s the thing to remember, the Listeria is on the outside of the fruit – it doesn’t spread throughout the flesh. So it’s not going to help to avoid certain types of fruits — the damage to your diet and health would far outweigh the potential safety benefits, statistically speaking. What to do?  Wash fruit as soon as you buy it with an antibacterial fruit and vegetable wash or, in a pinch, with antibacterial dish soap. Wash it again before you eat it, or better yet, peel it. But wash it even if you do peel it.
3. Foods that are refrigerated for long periods of time.
Listeria — unlike most types of bacteria, it can continue to grow under refrigeration. Refrigerating food does not prevent the growth of Listeria once it’s introduced. Cooking at high heat does kill Listeria, so ready-to-eat foods that are eaten without cooking are a potential source. Cheese is one of these, but interestingly soft ripened cheese and semi-soft cheese tested higher than hard cheeses. One solution is to put cheese into cooked dishes, but if you like your cheese sandwiches, there’s not a lot to be done.
4. Preserved and smoked meats.
Hot dogs, sausages, salami and all manner of preserved meats eaten cold are potential Listeria culprits, according to the FDA. The sampling procedure found Listeria in 6.4 percent of sausage samples, 4.8 percent of hot dogs sampled, and 6.5 percent of pâtes and meat spreads.
5. Root vegetables and ground-grown vegetables like squash

Vegetables that grow in the soil, like beets, carrots, and potatoes can come in contact with Listeria in the soil, as can those that grow on low-lying vines like zucchini and other types of squash. But please don’t let fear lead you to avoid veggies, which are healthiest foods in your diet. Instead, wash all veggies thoroughly and peel wherever appropriate. But wash before and after you peel, too — just peeling doesn’t cut it because the bacteria could be transferred on your hands.

miércoles, 22 de enero de 2014

USDA Email Reveals Poultry Industry Plans to Monitor Pathogens

The industry program is intended to set pathogen reduction goals

U.S. Department of Agriculture inspectors should not interfere with poultry industry efforts to collect chicken samples from processing facilities for a program intended to set pathogen reduction goals, according to an internal email from an administrator within the USDA’s Food Safety and Inspection Service (FSIS).
The program, organized by the National Chicken Council, aims to collect samples of chicken parts from “most all poultry establishments” in order to develop voluntary pathogen reduction performance goals
There is the potential that some in-plant inspectors and field supervisors may begin questioning this effort and take steps to force the establishments to turn over the results of the sampling. Because inspectors may mistakenly assume that the sampling could influence decision-making at individual poultry establishments In fact, any interruption of the industry’s data collection would have a negative impact on public health.
The poultry industry has the most responsibility to reduce pathogen loads on chicken parts, but USDA needs to answer questions about how those pathogen loads might be enforced. According to a 2012 UDSA report, the estimated national prevalence of Salmonella on chicken parts was 24 percent, while Campylobacter was 21 percent.
The data being collected by the poultry industry will be used to take a hard look at the process of cutting chicken into parts. It’s a way for the industry to prepare to meet or exceed whatever performance standards FSIS plans to set.

Source: FSIS, USDA

lunes, 20 de enero de 2014

Pasteurization: How Heat Keeps Pathogens at Bay

Debate about Pasteurizing raw milk

Pasteurizing milk became routine in the U.S. starting in the 1920s. Today, a number of other products on grocery store shelves, including eggs and juices, are also pasteurized.
While pasteurization doesn’t kill all the microorganisms in our food, it does greatly reduce the number of pathogens so that they are unlikely to cause disease. And, like with Pasteur’s beer, it reduces spoilage organisms, extending our food’s “shelf life.”The method of pasteurization simply involves heating food to a specific temperature for a certain length of time and then immediately cooling it. Manufacturers use various time-temperature combinations when treating their products.
The specific temperatures allotted for pasteurization are based on the ability to kill the most heat-resistant of pathogens. Campylobacter will die pretty quickly at 72 C°, but processors need higher temperatures to kill.
Of course, pasteurization is in the news these days because of the debate about raw milk.
The market is growing of consumers seeking unprocessed foods or those wanting to support small farms. And advocates of raw milk defend it for a number of reasons, particularly arguing that pasteurization reduces the nutritional and health benefits of milk.
But, without pasteurization, E. coli, Campylobcater and Salmonella can be much more prevalent in the milk. According to the Centers for Disease Control and Prevention (CDC), there were 148 outbreaks due to consumption of raw milk or raw milk products reported between 1998 and 2011. Among the victims, there were 2,384 illnesses, 284 hospitalizations and two deaths.
The health benefits that proponents are removed by pasteurization. Have not been clearly demonstrated in evidence-based studies and, therefore, do not outweigh the risks of raw milk consumption. The American Academy of Pediatrics, AAP said. “Substantial data suggest that pasteurized milk confers equivalent health benefits compared with raw milk, without the additional risk of bacterial infections.”

viernes, 17 de enero de 2014

CDC Updates Salmonella Heidelberg Cases to 430 People in 23 States and Puerto Rico

FSIS is prepared to take additional actions or expand the investigation

The U.S. Centers for Disease Control and Prevention announced Thursday afternoon that, as of Jan. 15, a total of 430 persons infected with seven outbreak strains of Salmonella Heidelberg have been reported from 23 states and Puerto Rico.

The situation prompted a public health alert on Oct. 7, 2013, from the U.S. Department of Agriculture’s Food Safety and Inspection Service due to concerns that the illness was associated with chicken products produced at three Foster Farms processing facilities in California.

Most of the ill persons (74 percent) have been reported from California. The number of those ill identified in each state is as follows: Alaska (1), Arkansas (1), Arizona (19), California (321), Colorado (9), Connecticut (1), Delaware (1), Florida (4), Idaho (5), Illinois (1), Kentucky (1), Louisiana (1), Michigan (3), Missouri (5), North Carolina (1), Nevada (10), New Mexico (2), Oregon (10), Puerto Rico (1), Texas (10), Utah (2), Virginia (4), Washington (16), and Wisconsin (1).
Among 418 persons for whom information is available, illness onset dates range from March 1, 2013, to Dec. 26, 2013. Ill persons range in age from less than one year to 93 years, with a median age of 18 years. Fifty-two percent of ill persons are male. Thirteen percent of ill persons have developed blood infections as a result of their illness. Typically, approximately 5 percent of persons ill with Salmonella infections develop blood infections. No deaths have been reported.

Thirty-eight percent of ill persons have been hospitalized.The number of reported infections from the outbreak strains of Salmonella Heidelberg has returned to baseline levels, indicating that this particular outbreak appears to be over. However, activities related to this investigation are ongoing.
Epidemiologic, laboratory, and traceback investigations conducted by local, state, and federal officials indicate that consumption of Foster Farms brand chicken is the likely source of this outbreak of Salmonella Heidelberg infections.

This investigation is ongoing. FSIS is prepared to take additional actions or expand the investigation based on any new evidence.

lunes, 13 de enero de 2014

Healthy People 2020 Reviews Progress on Food Safety Objectives

Food Safety Modernization Act (FSMA) to production of food safety

The Healthy People 2020 initiative recently held a public webinar to update stakeholders on progress toward food safety objectives.
Addressing the goals to reduce infections from pathogens commonly transmitted through food, the Center for Food Safety and Applied Nutrition (CFSAN), cited new tools provided under the Food Safety Modernization Act (FSMA). The mandatory recall authority was used twice in 2013 to remove Salmonella-tainted pet treats.
For Shiga toxin-producing E. coli, the FSIS tests a broader range of source products for ground beef, has instituted sampling for 0:157 STECs, has incorporated new methodologies into outbreak investigations, and proposed regulations to label products containing mechanically tenderized beef. Also developing guidance for retail markets to help reduce Listeria contamination and a possible retail enforcement strategy.
To address preventing an increase in the proportion of non typhoidal Salmonella and Campylobacter jejuni isolates in humans that are resistant to antimicrobial drugs, the FDA’s plan to phase out the use of certain antibiotics in food animals.

A focus on reducing severe allergic reactions to food among adults has led FDA to modernize Good Manufacturing Practices (GMPs) to protect against allergen cross-contact, develop improved methods for the accurate measurement of allergens in complex foods, and tackle problematic food combinations such as undeclared milk in dark chocolate. FSIS took steps to refocus inspectors’ attention to potentially allergenic ingredients and now believes it has made an impact in reducing the number of recalls related to undeclared allergens.
And, to help increase the number of consumers following key food safety practices, FDA launched mobile-compatible versions of its site and 

miércoles, 8 de enero de 2014

FSIS Releases Comprehensive Strategy to Reduce Salmonella

The Salmonella Action Plan presents a number of aggressive steps the agency will take to prevent Salmonella-related illnesses

The U.S. Department of Agriculture’s (USDA) Food Safety and Inspection Service (FSIS) today released its Salmonella Action Plan that outlines the steps it will take to address the most pressing problem it faces--Salmonella in meat and poultry products. An estimated 1.3 million illnesses can be attributed to Salmonella every year.
The Salmonella Action Plan is the agency’s strategy to best address the threat of Salmonella in meat and poultry products.  The plan identifies modernizing the outdated poultry slaughter inspection system as a top priority. By focusing inspectors’ duties solely on food safety, at least 5,000 illnesses can be prevented each year. 
Enhancing Salmonella sampling and testing programs is also part of this comprehensive effort,  ensuring that these programs factor in the latest scientific information available and account for emerging trends in foodborne illness. Inspectors will also be empowered with the tools necessary to expeditiously pinpoint problems.  With more information about a plant’s performance history and with better methods for assessing in-plant conditions, inspectors will be better positioned to detect Salmonella earlier, before it can cause an outbreak.
In addition, the plan outlines several actions FSIS will take to drive innovations that will lower Salmonella contamination rates, including establishing new performance standards; developing new strategies for inspection and throughout the full farm-to-table continuum; addressing all potential sources of Salmonella; and focusing the Agency’s education and outreach tools on Salmonella.
These efforts will build upon the work that USDA has done over the past several years. In 2011, USDA strengthened the performance standards for Salmonella in poultry with a goal of significantly reducing illnesses by 20,000 per year.  And through the Salmonella Initiative Program, plants are now using processing techniques designed to directly reduce Salmonella in raw meat and poultry.  Thanks to these innovative technologies and tough policies, Salmonella rates in young chickens have dropped over 75 percent since 2006.
Learn more about the Salmonella Action Plan.

martes, 7 de enero de 2014

Como prevenir  el riesgo de adquirir Salmonella por el consumo de huevos

Medidas a considerar según la CDC para impedir la contaminación

Los huevos, al igual que la carne, el pollo, la leche y otros alimentos, no causan enfermedades si se manipulan de manera adecuada. Los huevos en su cáscara se conservan mejor en el refrigerador y representan menos riesgos de enfermar si se cocinan completamente de manera individual y se consumen  de inmediato.
Al cocinar los huevos, se reduce el número de bacterias presentes; sin embargo, un huevo con la yema líquida sigue presentando un riesgo mayor que otro con la yema bien cocinada. Las claras y las yemas poco cocidas han sido asociadas a brotes de infecciones por Salmonella Enteritidis. Las claras y las yemas de los huevos deben consumirse poco después de prepararse y no se deben mantener bajo el calor o a temperatura ambiente por más de 2 horas.

Principales medidas a considerar para prevenir el riesgo:
1.    Mantener los huevos  refrigerados  (≤7°C) todo el tiempo.
2.    Lavarse las manos, los utensilios de cocina y las superficies de preparación de comida con agua y detergente si han estado en contacto con huevos crudos.
3.    Los huevos deben cocinarse hasta que la clara y la yema estén firmes y consumirse poco después de preparados.
4.    Evitar el consumo de huevos crudos o a medio cocer, especialmente en niños pequeños, ancianos y personas con sistemas inmunitarios debilitados.
Una persona infectada por las bacterias de Salmonella Enteritidis presenta fiebre, dolor de estómago y diarrea a partir de las 12 a 72 horas después de haber consumido un alimento o una bebida contaminado. La enfermedad dura generalmente de 4 a 7 días y en la mayoría de los casos las personas se recuperan sin necesidad de recibir un tratamiento con antibióticos. Sin embargo, la diarrea puede ser muy intensa y hacer que la persona se enferme tanto que requiera ser hospitalizada.

lunes, 6 de enero de 2014

CDC reports first STEC documented cases of E.coli O104 illnesses in the USA

Clinical laboratories should adhere to STEC testing recommendations because they are critical for identification of rare or novel STEC pathogens.

Six illnesses and one death associated with E.coli 0104:H4 but none of the US patients recalled consumption of raw fenugreek sprouts. This is the second-largest shiga toxin–producing E.coli (STEC) outbreak worldwide and the first documented STEC O104:H4 illnesses in the US.
The previous outbreak killed 50 and sickened 4,000, was centered in Northern Germany but affected 16 countries in Europe and North America.
The recent outbreak that occurred between May 26 and June 16, six confirmed cases were identified in five states: Arizona (one), Massachusetts (one), Michigan (two), North Carolina (one), and Wisconsin (one). The ages of patients ranged from 38 to 72 years, two patients were female and five reported travel to or from Germany in the three weeks before their illness. Patients reported consumption of fresh produce while in Germany, such as tomatoes, lettuce, and cucumbers. However, none recalled eating sprouts, the food vehicle ultimately implicated. “These events highlight challenges in investigating outbreaks, particularly those caused by rare pathogens or associated with food vehicles that are consumed in small quantities as part of other dishes,” said the report.
Clinical laboratories should adhere to STEC testing recommendations because they are critical for identification of rare or novel STEC pathogens. Four (66%) patients were reported by physicians to have developed HUS, requiring dialysis and ventilator support and one patient died.
Surveillance involved case-finding, use of laboratory testing protocols specific to non-O157 STEC, interviews to identify potential exposures of interest, and documentation of clinical courses.
Researchers from Michigan State University later decoded the E.coli strain, finding increased production of Shiga toxin was the probable reason for its virulence as it has a longer incubation period.
The outbreak described in this report, relies on having robust public health infrastructure in place. Such infrastructure, including systematic disease surveillance, laboratory capacity, and the ability to conduct epidemiologic and traceback investigations, is essential for maintaining a safe food supply. Sustaining and enhancing capacity to conduct these activities, both internationally and domestically, will be critical in confronting future challenges related to known and novel pathogens.

jueves, 2 de enero de 2014

The 10 Biggest Foodborne Illness Outbreaks of 2013

Chicken and fresh produce lead the pack

Food Safety News has compiled a list of 10 of the biggest U.S. outbreaks in 2013 (this list excludes Norovirus outbreaks and only includes pathogenic outbreaks associated with grocery products or restaurants..

10. E. coli O157:H7 from Glass Onion chicken salads, 33 sick. Trader Joe’s customers in four states fell ill after eating one of two pre-made salad products from Glass Onion Catering. At least seven people were hospitalized, with two developing hemolytic uremic syndrome (HUS).

9. Salmonella from Hacienda Don Villo in Channahon, IL, 35 sick. Health investigators traced 35 Salmonella illnesses back to this Mexican restaurant in Grundy County, but they could never pinpoint the exact food source. At least one person was hospitalized, and one employee was among those who tested positive for Salmonella

8. E. coli O121 from frozen Farm Rich foods, 35 sick. Prompting a large recall of frozen mini pizza slices, cheeseburgers and quesadillas, this outbreak sickened predominantly minors across 19 states. Of those confirmed ill, 82 percent were 21 years of age or younger. Nine were hospitalized. The company recalled all products created at one Georgia plant between June 2011 and March 2013.

7. Salmonella from imported cucumbers, 84 sick. Investigators eventually traced this outbreak of Salmonella Saintpaul back to cucumbers imported from Mexico. Of those confirmed ill, 17 were hospitalized. The importers were barred from bringing more products into the U.S. until they could prove the products were not contaminated. 

6. E. coli O157:H7 from Federico’s Mexican Restaurant in Litchfield Park, AZ, 94 sick. Investigators have implicated lettuce served at the restaurant as the likely source of the E. coli, but no other restaurants in the area had cases connected to them. The lettuce may have been cross-contaminated from another food at the restaurant, or the restaurant may have received a highly contaminated batch. Two victims developed HUS as a result of their infections. 

5. Salmonella from Foster Farms chicken, 134 sick. The first of two Foster Farms outbreaks in 2013 hit Washington and Oregon the hardest, but then spread out across 13 states. At least 33 people were hospitalized, with infections likely resulting from cross-contamination or undercooking of highly contaminated raw chicken. Foster Farms has not issued a recall for either of the two major outbreaks caused by chicken it produced this year. 

4. Hepatitis A from Townsend Farms frozen organic berries, 162 sick. At least 71 people were hospitalized after eating an organic berry mix purchased at Costco stores in the Southwest. The exact source of the outbreak was eventually traced back to pomegranate seeds from Turkey which were contained within the mix.

3. Salmonella from dining at Firefly restaurant in Las Vegas, NV, 294 sick. Patrons of this popular Las Vegas tapas restaurant fell ill after dining within a five-day stretch in April. The owners ultimately closed up shop and re-opened the restaurant in a new location. 

2. Salmonella from Foster Farms chicken, 416 sick. While this outbreak appears to be ongoing, hundreds of individuals have fallen ill over the course of the year in connection with raw chicken processed at Foster Farms facilities in California. At least 162 people have been hospitalized after likely undercooking the contaminated raw chicken or handling it in a way that lead to accidental cross-contamination. Foster Farms has refused to issue a recall, and cases continue to appear as recently as early December. 

1. Cyclospora from salads and cilantro, 631 sick. The outbreak of this foodborne parasite also takes the title for most confusing, as it appeared to be two separate Cyclospora outbreaks working in tandem. One set of patients – predominantly from Iowa and Nebraska – clearly appeared to be connected to Olive Garden and Red Lobster restaurants (both owned by Darden Restaurants), while, just weeks later, patients in Texas began cropping up with no apparent connection to those restaurants. The Darden illnesses were tentatively traced to lettuce supplier Taylor Farms de Mexico, but no contamination could be found at the farms. Meanwhile, many of the Texas illnesses seemed to implicate fresh cilantro grown in Puebla, Mexico. 


E. coli: The big six strains are here

USDA and CDC start to test beef for more enterohemorrhagic strains of E. coli

Most strains of Escherichia coli, or E. coli, are harmless. But some produce toxins that can sicken or kill people. The USDA banned the most commonly enterohemorrhagic strain identified — E. coli O157:H7 — from raw ground beef, a pathogen that can attach to vegetables and survive. It’s scheduled to ban another six enterohemorrhagic strains in past June. Birds and flies are usual vectors of these enteric pathogens.
Here are some outbreaks associated with those six enterohemorrhagic strains:
E. coli O26: A multi-state outbreak linked to raw clover sprouts at Jimmy John’s sandwich shops sickened more than two dozen people and hospitalized seven this year. In 2010, Cargill recalled about 8,500 pounds of ground beef because it may have been contaminated with this strain and led to three illnesses in New York and Maine. A more recent outbreak due to O26 was reported recently in Germany.
E. coli O45: Through 2008, CDC had identified three outbreaks linked to this strain. Two were suspected to involve infections from contact with animals at a petting zoo and a family farm.
E. coli O103: In 2000, two people were hospitalized in an outbreak possibly linked to water-based punch at a banquet hall in Washington State.
E. coli O111: The first community outbreak linked to this strain in the United States sickened five dozen girls attending a Texas cheerleading camp in 1999. More recently, one person was killed in a 2008 outbreak traced to an Oklahoma restaurant; hundreds were sickened. In both cases, the exact source of contamination is unknown.
E. coli O121: As of 2008, the largest outbreak tied to this strain involved contaminated lettuce that sickened 42 people at a catered event in Utah.
E. coli O145: Shredded romaine lettuce from an Ohio processing plant was contaminated with this strain and sickened more than two dozen people in 2010. Three developed kidney failure. No deaths have been reported.

Sources: CDC and USDA