Category Archives: Salmonella

USA – CDC – Lettuce, Other Leafy Greens, and Food Safety

CDC

Leafy greens arranged on a white background

Vegetables are an important part of a healthy diet. Leafy vegetables (called leafy greens on this page), such as lettuce, spinach, cabbage, kale, and bok choy, provide nutrients that help protect you from heart diseasestroke, and some cancers.

But leafy greens, like other vegetables and fruits, are sometimes contaminated with harmful germs. Washing leafy greens does not remove all germs. That’s because germs can stick to the surface of leaves and even get inside them. If you eat contaminated leafy greens without cooking them first, such as in a salad or on a sandwich, you might get sick.

Although anyone can get a foodborne illness, sometimes called food poisoning, some groups of people are more likely to get one and to have a serious illness. These groups include:

  • Adults aged 65 and older
  • Children younger than 5 years
  • People who have health problems or take medicines that lower the body’s ability to fight germs and sickness (a weakened immune system)external icon
  • Pregnant people

Eating Leafy Greens

Are leafy greens safe to eat?

Millions of servings of leafy greens are eaten safely every day in the United States. But leafy greens are occasionally contaminated enough to make people sick. To reduce your chance of getting sick, always follow the steps for safely handling and preparing leafy greens before eating or serving them.

Are leafy greens safe for my pet to eat?

Some animals can get sick from some germs that also make people sick. Always follow the steps for safely handling and preparing leafy greens before feeding them to pets and other animals. Never feed recalled food to pets or other animals.

Safely Handling and Preparing Leafy Greens

Do I need to wash all leafy greens?

Prewashed greens don’t need to be washed again. If the label on a leafy greens package says any of the following, you don’t need to wash the greens:

  • Ready-to-eat
  • Triple washed
  • No washing necessary

Prewashed greens sometimes cause illness. But the commercial washing process removes most of the contamination that can be removed by washing.

All other leafy greens should be thoroughly washed before eating, cutting, or cooking.

What is the best way to wash leafy greens?

The best way to wash leafy greens is by rinsing them under running water. Studies show that this step removes some of the germs and dirt on leafy greens and other vegetables and fruits. But no washing method can remove all germs.

Follow these steps to wash leafy greens that you plan to eat raw:

  • Wash your hands for 20 seconds with soap and water before and after preparing leafy greens.
  • Get rid of any torn or bruised leaves. Also, get rid of the outer leaves of cabbages and lettuce heads.
  • Rinse the remaining leaves under running water. Use your hands to gently rub them to help get rid of germs and dirt.
  • Dry leafy greens with a clean cloth or paper towel.

Should I soak leafy greens before washing them?

No. Do not soak leafy greens. If you soak them in a sink, germs in the sink can contaminate the greens. If you soak them in a bowl, germs on one leaf can spread to the other leaves. Rinsing leafy greens under running water is the best way to wash them.

Should I wash leafy greens with vinegar, lemon juice, soap, detergent, or produce wash?

Use plain running water to wash leafy greens and other produce. Kitchen vinegar and lemon juice may be used, but CDC is not aware of studies that show vinegar or lemon juice are any better than plain running water.

Do not wash leafy greens or other produce with soap, detergent, or produce wash. Do not use a bleach solution or other disinfectant to wash produce.

What other food safety steps should I keep in mind when I select, store, and prepare leafy greens and other produce?

  • Select leafy greens and other vegetables and fruits that aren’t bruised or damaged.
  • Make sure pre-cut produce, such as bagged salad or cut fruits and vegetables, is refrigerated or on ice at the store.
  • Separate produce from raw meat, poultry, seafood, and eggs in your shopping cart, grocery bags, and refrigerator.
  • Store leafy greens, salads, and all pre-cut and packaged produce in a clean refrigerator with the temperature set to 40°F or colder.
  • Use separate cutting boards and utensils for produce and for raw meat, poultry, seafood, and eggs. If that isn’t an option, prepare produce before working with raw meat.
  • Wash utensils, cutting boards, and kitchen surfaces with hot, soapy water after each use.
  • Cook thoroughly or throw away any produce that touches raw meat, poultry, seafood or their juices.
  • Refrigerate cooked or cut produce, including salads, within 2 hours (1 hour if the food is exposed to temperatures above 90°F, like a hot car or picnic).

Germs, Outbreaks, and Recalls

How do leafy greens get contaminated with germs?

Germs that make people sick can be found in many places, including in the soil, in the feces or poop of animals, in refrigerators, and on kitchen surfaces.

Germs can contaminate leafy greens at many points before they reach your plate. For example, germs from animal poop can get in irrigation water or fields where theexternal icon vegetables grow. Germs can also get on leafy greens in packing and processing facilities, in trucks used for shipping, from the unwashed hands of food handlers, and in the kitchen. To prevent contamination, leafy greens should be grown and handled safely at all points from farm to fork.

Read a study by CDC and partners on what we have learned from 10 years of investigating E. coli outbreaks linked to leafy greens.

How common are outbreaks linked to leafy greens?

In 2014–2018, a total of 51 foodborne disease outbreaks linked to leafy greens (mainly lettuce) were reported to CDC. Five of the 51 were multistate outbreaks that led CDC to warn the public. Among those five outbreaks, two were linked to packaged salads, two were linked to romaine lettuce, and one could not be linked to a specific type of leafy greens.

Most recently, in 2019–2021, CDC investigated and warned the public about nine multistate outbreaks linked to leafy greens. Among those outbreaks, six were linked to packaged salads, one was linked to romaine lettuce, one was linked to baby spinach, and one could not be linked to a specific type of leafy greens. Learn about these outbreaks.

Most foodborne illnesses are not part of a recognized outbreak. The nearly 2,000 illnesses reported in 2014–2020 outbreaks linked to leafy greens represent only a small part of illnesses caused by contaminated leafy greens during those years.

Does CDC warn the public about every foodborne disease outbreak?

No. CDC does not warn the public about every foodborne outbreak—including ones linked to leafy greens. Some reasons for this include:

  • Most sources of foodborne outbreaks are never identified.
  • By the time a source is identified, it might no longer be in stores, restaurants, or homes. This can happen with foods that are perishable (foods that spoil or go bad quickly), such as leafy greens.
  • Most outbreaks affect people in only one state, so local or state health departments lead the work to identify, investigate, and communicate about those outbreaks. CDC typically communicates only about outbreaks that affect people in more than one state.

Investigating outbreaks linked to leafy greensexternal icon can be especially challenging. These outbreaks often go unidentified or unsolved.

What should I do with leafy greens that are part of a recall?

  • Never eat, serve, or sell food that has been recalled, even if some of it was eaten and no one got sick.
  • Return the recalled food to the store or throw it away at home.
    • Throw out the recalled food and any other foods stored with it or that touched it.
    • Put it in a sealed bag in an outside garbage can with a tight lid (so animals cannot get to it).
    • If the recalled food was stored in a reusable container, wash the container in the dishwasher or with hot, soapy water.
  • Follow CDC’s instructions for cleaning your refrigerator after a food recall.

Organic, Hydroponic, and Home-Grown Leafy Greens

Are organic leafy greens less likely to be contaminated than non-organic ones?

All kinds of produce, including organic leafy greens, can be contaminated with harmful germs at any point from farm to fork. CDC is not aware of any evidence that organic greens are safer.

Learn about some outbreaks linked to organic foodsexternal icon.

Are hydroponic or greenhouse-grown leafy greens less likely to be contaminated?

Leafy greens grown using these methods also can be contaminated with harmful germs at any point from farm to fork.

Learn about an outbreak linked to greenhouse-grown leafy greens.

How do I keep leafy greens in my garden safe to eat?

Home gardens can be an excellent source of fruits and vegetables. Follow these tips to help prevent food poisoning:

  • Plant your garden away from animal pens, compost bins, and manure piles.
  • Water your garden with clean, drinkable water.
  • Keep dirty water, including storm runoff, away from the parts of plants you will eat.

Learn about raised bed gardening pdf icon[PDF – 1 page].

Looking to the Future

What steps are industry and the government taking to make leafy greens safer?

CDC is collaborating with FDA, academia, and industry to investigate the factors that contribute to leafy greens contamination.

The leafy greens industry, FDA, and state regulatory authorities have been implementing provisions of the Produce Safety Ruleexternal icon as part of the FDA Food Safety Modernization Act (FSMA).external icon They are considering what further measures can be taken. FDA’s 2020 Leafy Greens STEC Action Planexternal icon describes the agency’s plans to work with partners to make leafy greens safer.

Research – Levels and genotypes of Salmonella and levels of Escherichia coli in frozen ready-to-cook chicken and turkey products in England tested in 2020 in relation to an outbreak of S. Enteritidis

Science Direct

Highlights

Six serovars, with S. Infantis and S. Enteritidis most common, found in 9% of samples

Serovar-specific PCR and Cragie’s motility method used for co-contaminated samples

All S. Enteritidis were outbreak strains and affected six products from two plants.

The highest MPN/g was 54 for S. Infantis and 28 and S. Enteritidis.

Detection of Salmonella spp. was associated with higher levels of generic E. coli.

Abstract

Frozen reformulated (FR) breaded chicken products have previously been implicated in causing human salmonellosis. A multi-country Salmonella enterica serovar Enteritidis outbreak involving several strains with >400 reported human cases in the UK occurred in 2020. Initially S. Infantis was detected in one sample from a case home but S. Enteritidis was then also isolated using a S. Enteritidis specific PCR in combination with isolation via a Craigie-tube. This prompted a survey to examine the presence and levels of Salmonella and E. coli in ready-to-cook FR poultry products in England in 2020.

From a total of 483 samples, including two from cases’ homes, Salmonella was detected in 42 chicken samples, these originated from six out of 53 production plants recorded. Salmonella detection was associated with elevated levels of generic E. coli (OR = 6.63). S. Enteritidis was detected in 17 samples, S. Infantis in 25, S. Newport in four and S. Java, S. Livingstone and S. Senftenberg in one each. The highest levels of Salmonella were 54 MPN/g for S. Infantis and 28 MPN/g for S. Enteritidis; 60% of the Salmonella-positive samples had <1.0 MPN/g. S. Enteritidis was detected together with S. Infantis in five samples and with S. Livingstone in one. Where S. Enteritidis was detected with other Salmonella, the former was present at between 2 and 100-fold lower concentrations. The Salmonella contamination was homogeneously distributed amongst chicken pieces from a single pack and present in both the outer coating and inner content. The S. Enteritidis were all outbreak strains and detected in six products that were linked to four production plants which implicated a Polish origin of contamination. Despite S. Infantis being most prevalent in these products, S. Infantis from only two contemporaneous human cases in the UK fell into the same cluster as isolates detected in one product. Except for one human case falling into the same cluster as one of the S. Newport strains from the chicken, no further isolates from human cases fell into clusters with any of the other serovars detected in the chicken samples.

This study found that higher E. coli levels indicated a higher probability of Salmonella contamination in FR chicken products. The results also highlight the importance of recognising co-contamination of foods with multiple Salmonella types and has provided essential information for detecting and understanding outbreaks where multiple strains are involved.

RASFF Alerts – Salmonella – Polish Chicken Products -Black Sesame Seeds – Polish Minced Turkey Meat – Polish MSM – Egg White – Pork Preparation – Raw Frozen Meat Preparation –

RASFF

Salmonella Infantis (in 3 out of 5 samples) in chicken thighs with skin with bone from Poland in Latvia

RASFF

Salmonella Infantis (in 2 out of 5 samples) chicken inner fillet from Poland in Latvia

RASFF

Salmonella spp. in chicken broiler fillet and quarters from Poland in Lithuania

RASFF

Salmonella Infantis (in 3 out of 5 samples) chicken quarter from Poland in Latvia

RASFF

Salmonella spp. in chilled chicken broiler wings from Poland in Lithuania

RASFF

Salmonella Infantis (in 3 out of 5 samples) minced turkey meat from Poland in Latvia

RASFF

Salmonella infantis in frozen chicken thigh meat from Poland in Italy

RASFF

Salmonella in mechanically separated meats ( MSM ) in Italy

RASFF

Salmonella in egg white in Belgium and the Netherlands

RASFF

Presence of salmonella spp in the preparation of pork from Italy in Austria

RASFF

Salmonella spp. in raw frozen meat preparation for dumplings from Germany in Spain

RASFF

Salmonella group O7 in black sesame seeds from India in Poland

RASFF Alerts – Animal Feed – Salmonella – Frozen Cat 3 Chicken Meat – Dried Beef Larynx Treats for Dogs

RASFF

Salmonella infantis in frozen chicken meat cat. 3 from Netherlands in Italy

RASFF

Salmonella spp. in dried beef larynx treats for dogs from Albania via Belgium in Germany

USA – FDA Core Investigation Table Update

FDA

Date
Posted
REF Pathogen
Total
Case Count

Status
3/16/

2022

1055 Salmonella
Saintpaul
Not Yet
Identified
60 Active
2/17/

2022

1056 Cronobacter
sakazakii
Powdered
Infant
Formula
See
Advisory
Active
2/9/

2022

1040 Listeria
monocytogenes
Not Yet
Identified
16 Active
2/2/

2022

1054 Enteroinvasive
E. coli
O143:H26
Not
Identified
16 Closed
1/10/

2022

1050 E. coli
O121:H19
Romaine 4 Closed
12/29/

2021

1052 E. coli
O157:H7
Packaged
Salad
See Outbreak
Advisory
Closed
12/20/2

021

1039 Listeria
monocytogenes
Packaged
Salad
See Outbreak
Advisory
Closed
12/15/2021 1048 Listeria
monocytogenes
Packaged
Salad
See Outbreak
Advisory
Active

USA – Microbiological Surveillance Sampling: FY17–19 Processed Avocado and Guacamole

FDA

The U.S. Food and Drug Administration collected and tested processed avocado, the main ingredient in guacamole, and finished guacamole as part of the agency’s proactive and preventive approach to deploying its sampling resources with the ultimate goal of preventing contaminated food from reaching consumers.

Assignment Overview

The assignment began in November 2017 and ended in September 2019. In total, the FDA collected and tested 887 samples of processed avocado and guacamole (domestic and imported product) for Salmonella spp. and Listeria monocytogenes. This total is smaller than the initial number of samples the agency set out to collect and test because the agency encountered factors that twice required a reduction of the collection target, as explained in the Sample Collection section of this report (page 6).

As to the design of the assignment, the FDA directed its field staff not to collect products that had undergone high-pressure processing (HPP) or products intended for HPP. HPP is a “kill step” validated to eliminate pathogenic microorganisms in food, and it is often used in the manufacture of processed avocado and guacamole. In seeking to exclude from the assignment products that had been HPP-treated, the FDA’s intent was to focus on products that posed the greatest risk to consumers.

The agency learned during its evaluation of the test results that some of the products collected had received HPP treatment but were not labeled as such. FDA staff worked retrospectively with industry to identify the HPP-treatment status of the samples collected but could not determine the status of a number of samples. Those samples were designated as “could not ascertain” for purposes of the data analysis.

Findings and Follow-up Actions

The FDA detected Salmonella spp.in two samples which were later determined to be distinct samples of the same brand of domestically manufactured guacamole from different lots. Neither sample had received HPP treatment. In addition, the agency detected Listeria monocytogenes in 15 samples from nine different firms. Of those 15 samples, eight had not been HPP treated. The HPP-treatment status of the other seven samples could not be ascertained.

When the FDA detected a pathogen in a domestic sample, agency personnel worked with the company that owned or distributed the affected product to conduct a voluntary recall in all cases in which product was available, or likely to still be available, to consumers. The FDA also conducted one follow-up inspection of a domestic facility, and state officials in Florida likewise conducted one domestic inspection. As to the imported samples, the agency refused to admit lots associated with the positives and placed the responsible companies on import alert. In all, the agency placed two firms on import alert. In addition, the agency conducted whole genome sequencing (WGS) analysis on the positives but was unable to determine whether processed avocado or guacamole were the food vehicle associated with any known human illnesses.

In addition to affirming that Salmonella spp. and Listeria monocytogenes may be present in processed avocado and/or guacamole, the assignment data show that the estimated prevalence of these pathogens in the non-HPP-treated samples was higher than in the HPP-treated samples. This finding appears to support other research that shows HPP is effective at neutralizing pathogenic microorganisms,[1] even as this assignment was not designed to compare possible differences based on HPP-treatment status. The findings also underscore the need for processors and others in the processed avocado and guacamole supply chain to comply with the FDA’s Preventive Controls for Human Food Rule[2] and for importers of these foods to comply with the FDA’s Foreign Supplier Verification Programs Rule.[3]


USA – Next Generation Farm recalls raw milk due to Salmonella

Food Poison Journal

New York State Department of Agriculture and Markets warned residents to avoid consuming raw milk from a farm in Adams due to possible salmonella contamination.

According to the Department, consumers should not consume unpasteurized raw milk from Next Generation Farm which is located at 9922 County Route 152 in Adams, which is located in Jefferson County.

According to a press release from the Department, a sample of the milk was collected by an inspector from the Department who discovered the product was contaminated with Salmonella. The producer was notified of a preliminary positive test result on March 9.

Further laboratory testing was completed on March 21 and confirmed the presence of Salmonella in the raw milk sample. The producer was prohibited from selling raw milk until subsequent sampling indicate that the product is free of harmful bacteria.

USA – FDA issues warning to New Mexico onion importer linked to Salmonella outbreak

Food Safety News

An import company in New Mexico is on notice from the FDA for not having food safety documents for a number of imported foods. The inspection was initiated because of an investigation of a multistate foodborne outbreak of Salmonella Oranienburg illnesses linked to whole, fresh onions imported from the state of Chihuahua, Mexico.

The outbreak has sickened more than 800 people in the United States and remains under investigation. The Centers for Disease and Prevention has not yet declared the outbreak over.

In its warning letter the Food and Drug Administration  acknowledged that the company initiated a voluntary recall on Oct. 22, 2021, of red, yellow, and white onions imported from its “suppliers (redacted)” in Chihuahua, Mexico, from July 1, 2021, through Aug. 25, 2021.

In the March 2, 2022, warning letter just made public by the FDA, the agency described a Nov. 16, 2021, Foreign Supplier Verification Program (FSVP) inspection of Keeler Family Farms in DemingNM.

USA – Salmonella accounted for nearly 80 percent of pathogen violations in U.S. food imports from 2002 to 2019

USDA

<i>Salmonella</i> accounted for nearly 80 percent of pathogen violations in U.S. food imports from 2002 to 2019

As the quantity of food imported into the United States continues to rise, it is increasingly important to minimize foodborne illness risks for U.S. consumers. Foods contaminated with pathogens or toxins can result in foodborne illnesses. A recent USDA, Economic Research Service (ERS) study examined the number of U.S. import refusals caused by pathogen/toxin contamination and which pathogens accounted for those safety violations. From 2002 to 2019, 22,460 pathogen/toxin violations were discovered among imported shipments. Salmonella was the most frequently identified agent among imported foods during the period with 80 percent, or 17,922 of total pathogen/toxin violations. Listeria recorded the second largest number of violations at 2,463, accounting for 11 percent of the total. It was followed by histamine with 804 violations (3.6 percent), aflatoxin with 663 violations (3 percent), and bacteria other than Salmonella or Listeria with 455 violations (2 percent). Those five most frequently detected pathogens and toxins accounted for 99.3 percent of the total pathogen/toxin violations from imported foods over the period. This chart was drawn from the ERS report Examining Pathogen-Based Import Refusals: Trends and Analysis From 2002 to 2019, published December 2021.

Research – Novel Salmonella Phage, vB_Sen_STGO-35-1, Characterization and Evaluation in Chicken Meat

MDPI

Salmonellosis is one of the most frequently reported zoonotic foodborne diseases worldwide, and poultry is the most important reservoir of Salmonella enterica serovar Enteritidis. The use of lytic bacteriophages (phages) to reduce foodborne pathogens has emerged as a promising biocontrol intervention for Salmonella spp. Here, we describe and evaluate the newly isolated Salmonella phage STGO-35-1, including: (i) genomic and phenotypic characterization, (ii) an analysis of the reduction of Salmonella in chicken meat, and (iii) genome plasticity testing. Phage STGO-35-1 represents an unclassified siphovirus, with a length of 47,483 bp, a G + C content of 46.5%, a headful strategy of packaging, and a virulent lifestyle. Phage STGO-35-1 reduced S. Enteritidis counts in chicken meat by 2.5 orders of magnitude at 4 °C. We identified two receptor-binding proteins with affinity to LPS, and their encoding genes showed plasticity during an exposure assay. Phenotypic, proteomic, and genomic characteristics of STGO-35-1, as well as the Salmonella reduction in chicken meat, support the potential use of STGO-35-1 as a targeted biocontrol agent against S. Enteritidis in chicken meat. Additionally, computational analysis and a short exposure time assay allowed us to predict the plasticity of genes encoding putative receptor-binding proteins.