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MIT Developed Novel Pathogen System Based on Janus Emulsions

Rapid methods for pathogen testing have been gaining acceptance in the food industry. Recent advances in technology result in faster detection and identification of pathogens, more convenient, more sensitive, more reproducible, and more specific than conventional methods. Many new methods are available involving antibody-based assays, genetic amplification methods, and newer sensor development methods. 
However, the industry is always looking for faster, simpler and cost effective new methods. An article in ACS Central Science describes the work of researchers at Massachusetts Institute of Technology (MIT) that are developing a new method for pathogen detection, utilizing Janus emulsions. The team is lead by Timothy Swager and Qifan Zhangis the lead author.
The test is based on the analysis of liquid droplets (Janus droplets, or Janus emulsion) that are powerful liquid phase sensing particles. These droplets are formed from two equally sized hemispheres. One half is composed of a fluorocarbon and the other from a hydrocarbon.
The fluorocarbon is denser than the hydrocarbon when droplets sit on a surface, therefore the fluorocarbon orients to the bottom. When the different hemispheres are functionalized to have orthogonal physical and biochemical properties, they can be used as sensors. Consequently Janus particles with covalently modified surfaces have been used for sensing applications.
From above the droplets are transparent but when viewed sideways they appear opaque. This property relates to the way that light passes through the droplet, and it is the path of light that can be adapted to make the sensor.
Building on this the scientists at MIT developed a surfactant molecule that contains mannose sugar to form the top half of the droplet surface. These molecules are capable of binding to a protein called lectin. Lectin is a protein that can bind specifically to certain sugars and cause agglutination of particular cells, and it is found on the surface of strains of E. coli.
The emulsion assay uses the carbohydrate surfactant molecule, which self-assembles at the droplet surfaces during the emulsification process. Therefore, no further element is required for bacterial recognition. These changes in the alignment of the Janus droplets are used for the detection of analytes.  The droplets are capable of binding to specific bacterial proteins. The mannose surfactant functionalized emulsion assay described in this work was designed specifically for E. coli as a model system.  
Whenever E. coli is present the droplets attach to the Lectin proteins. This causes the droplets to clump together causing light to scatter in many directions. The Janus emulsion assay enables detection of E. coli bacteria at a concentration of 104 cfu/mL.   The figure below shows the effect of the agglutination process.
On the left, Janus droplets are viewed from above. After the droplets encounter their target, they clump together (right). Credit: Qifan Zhang
The intrinsic optical lensing behavior of the Janus droplets also enables both qualitative and quantitative detection of protein and E. coli bacteria. The qualitative assay is very simple and can be scanned with a  Smartphone. To demonstrate the simplicity of the agglutination assay for qualitative results, the researchers placed inside a Petri dish QR barcode (Quick Response Code two-dimensional barcode)
As seen in the figure above when E. coli are present, the droplets clump together and the QR code can’t be read.( Credit: Qifan Zhang)
To precisely quantify the degree of agglutination, the researchers implemented an image processing program to calculate the percentage of area covered by agglutinated Janus emulsions and to evaluate the differences in optical intensity of the images before and after exposure to ConA (concanavalin A, serves as a functional substitute for E. coli bacteria). The program uses the adaptive threshold algorithm to distinguish areas with higher transparency (pristine Janus emulsions) from the opaque regions (agglutinated Janus emulsions).
The MIT team plans to create droplets customized with more complex sugars that would bind to different bacterial proteins. In this paper the researchers used a sugar that binds to E. coli, but they expect that they could adapt the sensor to other pathogens.
The researchers are now working on optimizing the food sample preparation so they can be placed into the wells with the droplets. They also plan to create droplets customized with more complex sugars that would bind to different bacterial proteins. The team leader, Savagatrup says “You could imagine making really selective droplets to catch different bacteria, based on the sugar we put on them”.
The researchers are also trying to improve the sensitivity of the sensor, which currently is similar to existing techniques but has the potential to be much more sensitive, they believe. They hope to launch a company to commercialize the technology within the next year and a half.
Explaining a clear advantage of the technology, one of the lead scientists, Professor Timothy Swager, said: “What we have here is something that can be massively cheaper, with low entry costs. The sensor has been tested out with multiple samples of the infective bacterium and the results are sufficiently successful for the sensor to be considered for commercialization”

Salmonella Concerns Triggers a Recall of Banquet Frozen Chicken Nuggets due to Tainted Desert


Banquet Chicken Nuggets with Mac & Cheese

Banquet Chicken Nuggets with Mac & Cheese has been recalled due to possible salmonella contamination. Frozen dinners contain Chicken Nuggets, mac and cheese and brownies. It is the brownies flour mix that might be the culprit of the Salmonella contamination.
The U.S. Department of Agriculture’s Food Safety and Inspection Service (FSIS) alerted  consumers that the brownie mix dessert included in the breaded chicken nugget meal trays produced by Conagra Brands, Inc., of Marshall, Mo, may be contaminated with Salmonella.
The recall affects 110,817 pounds of frozen meals, was done out of an abundance of caution after the company notified FSIS that the source ingredient used in the brownie mix may be contaminated with Salmonella. The problem was discovered when Conagra Brands Inc. received a notification from a supplier that an ingredient used in the brownie mix may be contaminated with Salmonella.
7.4 oz. vacuum-packed trays containing “BANQUET Chicken Nuggets with Mac & Cheese” with Code 3100080921 and with a “BEST IF USED BY” date of July 20, 2018. The products bear FSIS establishment number “P-9” printed on the side of the box.
There have been no confirmed reports of illnesses yet, and the recall is issued out of caution for consumers’ safety. According to the release the meals were produced by Conagra Brands in Missouri and sold nationwide,.  The brownie mix used to make the desserts in the meals may have been contaminated with salmonella, the agency said. 

Mango Popsicles Recalled Due to the Risk of Salmonella Enteritidis

The FDA announced the recall of 4000 units of Hand crafted Paleteria, Mango Flavored Ice cream because it has the potential to be contaminated with Salmonella Enteritidis.
The ice cream was distributed in Georgia, Alabama, North Carolina and South Carolina through retail stores, by direct delivery. It comes in a clear bag with La Granja logo, Mango Flavor Ice Cream and the dates of expiration are 210218 (February 21, 2018) and 280218 (February 28, 2018). UPC code 0010439212.
No illnesses have been reported to date. The recall was a result of a routine sampling program by The Georgia Department of Agriculture. The company has ceased the production and distribution of the product as the FDA and the company continues their investigation as to what caused the problem.

Lay’s Kettle Cooked Potato Chips Re Recalled due to Potential Presence of Salmonella

The FDA reported that Frito-Lay announced that it voluntarily recalls select Jalapeño Flavored Lay’s Kettle Cooked potato chips and Jalapeño Flavored Miss Vickie’s Kettle Cooked potato chips due to the potential presence of Salmonella in the seasoning.
The recall is the direct result of a supplier’s recent recall of a seasoning blend which includes jalapeño powder that could contain Salmonella. Although no Salmonella was found in the seasoning supplied to Frito-Lay, the company has decided to recall these products out of an abundance of caution.
No illness related to this matter has been confirmed to date. The products have been distributed in retail stores and via foodservice, vending and other channels throughout the U.S.

Some Final Thoughts

We see more and more recalls due to suppliers notifications. This is a result of the FSMA regulations, that requires every food distributor and food manufacturer to track the products they manufacture and distribute and be able to quickly recall them.
The ability to remove products from the market quickly and effectively is imperative to all food producer and distributor. A written recall program with an action plan that is carefully constructed, tested and evaluated to ensure efficiency must be available. It is seen as the safety net that can prevent consumers from buying or consuming a potentially harmful food product.
Most of the recalls, however, are still not happening fast enough to eliminate defective product to end up in new products. This is a very wasteful way to keep the food supply safe. As shown in the Banquet Chicken Nuggets with Mac & Cheese frozen dinners tons of perfectly good chicken nuggets are being thrown away because of the contaminated flour used in the small desert portion.

How Safe Food Trucks Are?


E. coli outbreak closed Chicken & Rice Guys in Boston

According to the Boston Globe the city of Boston received an anonymous complaint about customers getting sick after buying food from Chicken & Rice Guys trucks.
The Boston Health department confirmed 7 cases of E. coli food poisoning originating from the Allston location that supplies the food for the chain. The company has 5 trucks that rotate in the Boston area. They also have regular, brick and mortar, restaurants in Allison, Boston, and Medford. The Chicken & Rice Guys began the food truck business in 2012.
Fifteen of the chain customers were infected with E. coli O157:H7, with 10 of them requiring hospitalization.  None of them were elderly or children, the typical sensitive population to E. coli infections.  According to the Globe story Dr. Anita Barry, director of the Infectious Disease Bureau at the Boston Public Health Commission, said that none of those sickened had developed hemolytic uremic syndrome (HUS).
The Health Department closed the restaurants and food trucks during the investigation. Most of the cases had a connection to the Allison location. An investigation is being conducted by the Department of Public Health in Boston, in conjunction with health departments in Medford and Somerville, and the U.S. Centers for Disease Control and Prevention.
The Health Department of Boston is testing the food taken from the restaurants as well as stool samples from all its employees. It is not clear at this time whether the food caused the outbreak or the employees contaminated the food with their hands.
The company’s CEO Ian So, apologized to the customers on Facebook in a video in which he said: “First and foremost, I’m really sorry to everyone that got sick.” “If you know our team and dedication…it hurts a lot. Obviously we can do a better job.” He also said “we decided to voluntarily shutdown affected operations”  Ian So also said that although the restaurants passed inspection they will continue to keep them closed until the reasons for the outbreak are determined.
The company hired a food safety consultant and an outside cleaning firm to “deep clean” all its restaurant locations and the food trucks.

The question: Is it safe to eat from a truck?

Food trucks have rapidly multiplied on Boston streets and plazas, with 75 gourmet-style restaurants on wheels now serving up any food imaginable, with cheap convenient food for the lunch crowd.
In Boston, 41 % of these trucks have been cited for food safety violations that can put their customers at risk of food poisoning, according to a Globe review of all inspection records.
It is generally more difficult to ensure the safety of meals from food trucks as compared to traditional restaurants. This is because trucks lack of the same infrastructure of brick and mortar restaurants. However, a study by the Institute of Justice released in 2014, Showed that food trucks and carts have similar or fewer number of violations as regular restaurants.
Contradicting this study was an investigation conducted by the California Environmental Health Specialists Network (EHS-Net).  It determined that of the 95 mobile food trucks assessed, 94.73% exhibited at least one critical risk factor. The study demonstrated that mobile food trucks would benefit from similar inspection practices as regular restaurants. It concluded that these “restaurants on wheels” are difficult and time consuming to locate, creating a considerable resource drain to an already taxed inspection workforce. Most of the 57 California environmental health agencies surveyed in the study indicated that they conduct only one “scheduled” inspection per year. A reason for it the inability to locate food trucks due to limited resources.
Complying with health standards is tougher for food trucks than for traditional restaurants.  However, one actually is more likely to get sick because an employee had bad hygiene, on a truck or in a restaurant. Filthy hands are a major reason for food contamination on food trucks and are a major suspect in the Chicken & Rice Guys case.
A lack of water supply and improper storage of food are the two main food safety challenges for food trucks. However, all these concerns do not seem to discourage truck patrons, judging from the long lines formed at lunch time.

Outbreak of E. coli infection in flour triggers a major recall in Canada

The Public Health Agency of Canada is investigating an outbreak of Escherichia coli O121 that was linked to flour from Robin Hood. So far there have been 25 cases of E. coli O121 in four provinces: British Columbia (12), Saskatchewan (4), Alberta (4) and Newfoundland and Labrador (5) with a matching genetic fingerprint in all these cases.
During the food safety investigation, samples of Robin Hood flour were collected and tested positive for E. coli O121. The illness onset dates range from November 2016 to late February 2017. Six individuals have been hospitalized. These individuals have since recovered or are recovering. No deaths have been reported. The 54% of the ill people were males, with an average age of 24 years. 
According to the company that produced the Robin Hood flour, the recalled product was produced at a mill in Saskatoon.
More Recall details:  On March 28, 2017 – Smucker Foods of Canada Corp. recalled Robin Hood brand All Purpose Flour, Original from the marketplace due to possible E. coli O121 contamination. This recall was triggered by findings by the Canadian Food Inspection Agency (CFIA) during its investigation into a foodborne illness outbreak.
The affected flour comes in 10-kilogram bags with a best before date of April 17, 2018, and was sold in British Columbia, Alberta, Saskatchewan and Manitoba.
This outbreak reminds us of last year’s General Mill outbreak in the US that sickened 63 people in 24 states, with 17 people hospitalized. The median age in that outbreak was low, at 18, mostly because teenagers and children are more likely to eat raw dough and play with products made with raw dough. 
The Canadian and the General Mills outbreaks is a reminder that it is not safe to taste or eat raw dough or batter, regardless of the type of flour used, as raw flour can be contaminated with dangerous bacteria such as E. coli.

Recall due to E. coli in protein bars

The FDA announced the recall of 36,957 Yogurt Peanut Crunch bars from Pro Sports Club of Bellevue, WA because on March 23, 2017 the products may have been contaminated with Escherichia coli O157:H7.
The Yogurt Peanut Crunch Bars were sold directly to clients at the PRO Sports facilities in Washington (Bellevue, Redmond and Seattle cities) between August 8, 2016 and March 10, 2017. The product was also sold via the Internet. No illnesses related to the consumption of the Yogurt Peanut Crunch Bars have been reported to date.
The recall was initiated after the manufacturer was notified that an ingredient used in the Yogurt Peanut Crunch Bars was recalled by its supplier Soy Nut Butter Company of Glenview, Illinois because it was found to contain E. coli O157:H7.
This is a secondary recall due to a soy-based peanut butter substitute linked to a nationwide E. coli outbreak that happened earlier this month. Of the 23 confirmed E. coli victims in the soy butter outbreak, 20 are younger than 18. Ages range from 1 to 48 with a median age among victims of 8 years old. Ten of the victims had severe symptoms that required hospitalization and seven of them developed HUS. Twenty of the 23 victims reported eating I.M. Healthy brand soy nut butter products in the days before they became ill.

H & B Packing Co., Inc. Recalls Boneless Beef Products Due to Possible E. coli O103 Contamination

On March 19, U.S. Department of Agriculture’s Food Safety and Inspection Service (FSIS) announced that H & B Packing Co., Inc., a Waco, Texas establishment, recalled  approximately 79,461 pounds of boneless beef products that may have been contaminated with the rare E. coli O103.
The problem was discovered when FSIS was notified by the State of Texas’ Meat Safety Assurance Unit about a positive non-O157 Shiga toxin-producing E. coli sample. There have been no confirmed reports of illnesses due to consumption of these products. The beef products were shipped to food manufacturers in Texas.