Category Archives: Food Micro Blog

Research- Effect of cultivars and irrigation waters on persistence of indicator bacteria on lettuce grown in high tunnel

Wiley Online


Effect of irrigation with groundwater (GW), primary‐treated wastewater (PTWW), secondary‐treated wastewater (STWW), and roof‐collected rainwater (RCR) on the microbial quality of lettuce cultivars “Annapolis,” “Celinet,” and “Coastline” grown in high tunnel was investigated. Lettuce plants were spray irrigated with irrigation waters once a week for 2 weeks and analyzed for indicator and pathogenic bacteria. PTWW irrigation resulted in the highest Escherichia coli recovery on the lettuce plants (4.7 log MPN/g) as compared to irrigation with other three waters on 0 day post irrigation (dpi). Lettuce cultivars affected the bacterial die‐off rate, where E. coli populations reduced the most by 1.5 log MPN/g on “Annapolis” lettuce on 2 dpi. The STWW and RCR irrigation did not significantly influence indicator bacterial populations on lettuce as compared to GW irrigation. The STWW and RCR containing low populations of indicator bacteria may be suitable for lettuce irrigation in Mid‐Atlantic area without affecting its microbial quality.

USA – Salmonella outbreak traced to food ordered online

Food Safety News kswfoodworld Salmonella

Ten people were sickened by Salmonella from chicken legs in a Chinese city after eating food ordered online in mid-2018, according to a new report.

Researchers said the investigation highlights the role of online food delivery platforms as a new mode of foodborne disease transmission. Collaboration between public health agencies and online food delivery platforms is essential for timely intervention and to limit the scale of outbreaks.

From late June to early July 2018, 10 cases of diarrheal disease were reported at two hospitals in the Nanshan District of Shenzhen, China. This outbreak was suspected to be foodborne and was notified to the Shenzhen Center for Disease Control and Prevention (Shenzhen CDC), according to the study published in Emerging Infectious Diseases.

All 10 patients were university students who had diarrhea and fever. Seven of them also reported nausea and vomiting. Cases were from six different colleges of the same university but lived in different dormitories and did not know each other.

India – Kuttu causes food poisoning in Haryana, leaves 180 people ill

The Print

Yamunanagar: At least 180 people were taken ill due to food poisoning in Yamunanagar and Jagadhri towns of this district, health officials said on Thursday.

The officials said the people were admitted to civil hospitals at Jagadhri and Yamunanagar after they complained of vomiting and abdominal pain.

USA – Outbreak Investigation of Listeria monocytogenes: Enoki Mushrooms (March 2020)


Total Illnesses: 36
Hospitalizations: 30
Deaths: 4
Illness Onset Date Range: November 23, 2016 – December 13, 2019
States with Cases: AZ (2), CA (9), FL (2), HI (3), IN (1), KY (1), MA (2), MD (2), MI (1), MO (1), NC (1), NJ (1), NV (1), NY (4), RI (1), TN (1), VA (3)


Consumers should not eat and should check their refrigerators and throw away any recalled enoki mushrooms from Sun Hong Foods, Inc. and Guan’s Mushroom Co., because they may be contaminated with Listeria monocytogenes.

Restaurants and retailers should not sell or serve recalled enoki mushrooms distributed by Sun Hong Foods, Inc. and Guan’s Mushrooms Co.

FDA recommends that anyone who received recalled products use extra vigilance in cleaning and sanitizing any surfaces and containers that may have come in contact with these products to reduce the risk of cross-contamination. Listeria can survive in refrigerated temperatures and can easily spread to other foods and surfaces.

At this time, high risk groups, including the elderly, people with weakened immune systems or chronic diseases, pregnant women and their newborn babies, should not eat enoki mushrooms from Korea (Republic of Korea), even if they were not part of the recalls by Sun Hong Foods, Inc. and Guan’s Mushroom Co.

Consumers, restaurants, retailers, and high risk groups should discard and not eat, sell, or serve enoki mushrooms if they cannot tell where they came from.

Enoki mushrooms from Sun Hong Foods were sold in 200 g/7.05 oz clear plastic packaging with a green label; Sun Hong Foods, Inc. is labeled on the back of the packaging underneath the bar code. These products can also be identified by the UPC code: 7 426852 625810. Recalled product was sold to distributors in California, Florida, Illinois, Oregon, and Texas; and was sold to the following retailers: J&L Supermarket, Jusgo Supermarket, ZTao Market, New Sang Supermarket, Galleria Market. This distribution information has been confirmed by the firm, but product could have been distributed further, reaching additional states and retail locations. Laboratory analysis of a sample of these mushrooms found the presence of Listeria monocytogenes, and whole genome sequencing analysis of the sample found that the Listeria monocytogenes found in these mushrooms matched the outbreak strain.

Enoki mushrooms from Guan’s Mushroom Co. were sold in 200 g/7.05 oz clear plastic packaging with the description “Enoki Mushroom” in English, Korean, and French; Guan’s logo is on the front. On the back of the packaging, the UPC code 859267007013 and package code 14-1 are on the lower right corner. Recalled product was sold to distributors and wholesalers in California, New York, and Pennsylvania in white cardboard boxes with Guan’s logo in green color and code “#02473,” but could have been distributed further. Whole genome sequencing analysis is currently being conducted to determine if these products are linked to this outbreak.


FDA, CDC, and state and local partners are currently investigating a multistate outbreak of Listeria monocytogenes infections linked to enoki mushrooms. Enoki mushrooms are a long thin white mushroom, usually sold in clusters. They are especially popular in East Asian cuisine and are also known as enokitake, golden needle, futu, or lily mushrooms.

On March 23, 2020 Guan’s Mushroom Co. recalled all cases of its 200 g/7.05 oz packages of enoki mushrooms imported from Korea (Republic of Korea). The firm recalled product and ceased distribution after the California Department of Public Health found that a sample of these mushrooms was positive for Listeria monocytogenes. At this time, whole genome sequencing analysis is being conducted to determine whether or not enoki mushrooms from Guan’s Mushroom Co. are linked to this outbreak.

On March 18, 2020, the Korean Ministry of Food and Drug Safety (MFDS) issued a press release on their findings related to Listeria monocytogenes and enoki mushrooms. The government of the Republic of Korea investigated four companies that export enoki mushrooms to the United States and detected Listeria monocytogenes in enoki mushrooms produced by two firms in Korea. The Korean MFDS did not name the firms in the press release; the FDA is working to obtain this information. The Korean MFDS did not link product to any illnesses in Korea.

The Korean MFDS has recommended that enoki mushrooms should be cooked before being consumed and starting March 23, 2020, the Korean MFDS will require large production companies of enoki mushrooms to include additional labelling indicating that they should be cooked.

On March 9, 2020, Sun Hong Foods, Inc. recalled all enoki mushrooms imported from Korea (Republic of Korea). The firm recalled product after the Michigan Department of Agriculture and Rural Development found that a sample of these mushrooms was positive for Listeria monocytogenes. Whole genome sequencing analysis of the sample found that the Listeria monocytogenes found in these mushrooms matched the outbreak strain.

The investigation is ongoing to determine the source of contamination and if additional products are linked to illness. Additional information will be provided as it becomes available.

USA – FDA Advises Restaurants in California to Stop Selling Min Jiang Food Store Inc. Koi Koi Trading Salmon Products due to Possible Listeria Contamination



  • Restaurants in California that have received shipments of Min Jiang Food Store Inc. DBA Koi Koi Trading raw, ready-to-eat (RTE) salmon products between 3/9/2020 and 3/23/2020.
  • Consumers, especially women who are or could become pregnant, the elderly, and persons with weakened immune systems who have recently consumed raw, RTE salmon products from the listed restaurant locations and suspect they have food poisoning or other illness as a consequence of consumption contact a medical professional immediately.

The FDA is making available a list of restaurants that received recalled product between 3/17/2020 and 3/23/2020, as those products remain within the reported shelf-life of the recalled RTE salmon.


  • Product: Min Jiang Food Store Inc. DBA Koi Koi Trading raw, RTE salmon products received between 3/9/2020 and 3/23/2020.  These recalled raw, RTE salmon products may be incorporated into sushi products for consumption. These products are likely to be labeled “J Foods”.
  • Packaging: Salmon fillets are first wrapped in green parchment paper and then in clear plastic wrap. Salmon heads and bones (per customer request) are placed in clear plastic bags. Bagged/wrapped salmon is then placed into a Styrofoam box labeled “J Foods”.
  • Distribution Information: These salmon products were distributed to restaurants in California between 3/9/2020 and 3/23/2020. These products are typically sold fresh and do not have a long shelf life, though they can be frozen to extend the shelf life. The FDA is making available a list of restaurants that received the recalled product between 3/17/2020 and 3/23/2020. Records from the recalling firm show that the restaurants included in the link below have received RTE salmon from Min Jiang Food Store Inc. DBA Koi Koi Trading. Note: This list comprises firms to which Min Jiang Food Store Inc. DBA Koi Koi Trading has reported to the FDA that it distributed recalled product. This list may be both over and under inclusive, and firms may be added or removed as more information becomes available. The FDA currently does not have information to suggest that these products were distributed to retail locations other than restaurants.

List of restaurants that may have received this product from Min Jiang Food Store Inc. DBA Koi Koi Trading

Research – Salmonella enterica Elicits and Is Restricted by Nitric Oxide and Reactive Oxygen Species on Tomato

Frontiers in Microbiology

The enteric pathogen Salmonella enterica can interact with parts of the plant immune system despite not being a phytopathogen. Previous transcriptomic profiling of S. enterica associating with tomato suggested that Salmonella was responding to oxidative and nitrosative stress in the plant niche. We aimed to investigate whether Salmonella was eliciting generation of reactive oxygen species (ROS) and nitric oxide (NO), two components of the microbe-associated molecular pattern (MAMP)-triggered immunity (MTI) of plants. We also sought to determine whether this interaction had any measurable effects on Salmonella colonization of plants. Biochemical, gene expression and on-plant challenge assays of tomato vegetative and fruit organs were conducted to assess the elicitation of ROS and NO in response to Salmonella Newport association. The counter bacterial response and the effect of NO and ROS on Salmonella colonization was also investigated. We detected H2O2 in leaves and fruit following challenge with live S. Newport (p < 0.05). Conversely, NO was detected on leaves but not on fruit in response to S. Newport (p < 0.05). We found no evidence of plant defense attenuation by live S. Newport. Bacterial gene expression of S. Newport associating with leaves and fruit were indicative of adaptation to biotic stress in the plant niche. The nitrosative stress response genes hmpA and yoaG were significantly up-regulated in S. Newport on leaves and fruit tissue compared to tissue scavenged of NO or ROS (p < 0.05). Chemical modulation of these molecules in the plant had a restrictive effect on bacterial populations. Significantly higher S. Newport titers were retrieved from H2O2 scavenged leaves and fruit surfaces compared to controls (p < 0.05). Similarly, S. Newport counts recovered from NO-scavenged leaves, but not fruit, were higher compared to control (p < 0.05), and significantly lower on leaves pre-elicited to produce endogenous NO. We present evidence of Salmonella elicitation of ROS and NO in tomato, which appear to have a restricting effect on the pathogen. Moreover, bacterial recognition of ROS and NO stress was detected. This work shows that tomato has mechanisms to restrict Salmonella populations and ROS and NO detoxification may play an important role in Salmonella adaptation to the plant niche.

Research – Eating too much salt seems to impair body’s ability to fight bacteria

New Scientist listeria

Eating too much salt may impair the body’s ability to fight bacterial infections, according to studies in mice and in 10 human volunteers.

Christian Kurts at the University Hospital of Bonn in Germany and his team first showed that mice given a high salt diet were less able to fight kidney infections caused by E. coli and body-wide infections caused by Listeria monocytogenes, a common cause of food poisoning.

“The bacteria caused more damage before the immune system got rid them,” says Kurts.

Next, the team gave 10 healthy women and men who were 20 to 50 years old an extra 6 grams of salt a day on top of their normal diet, in the form of three tablets a day. After a week, some of their immune cells, called neutrophils, had a greatly impaired ability to engulf and kill bacteria compared with the same tests done on each individual before they took extra salt.