Category Archives: Microbiology Risk

USA – Leafy Greens STEC Action Plan

FDA

Leafy greens are among the most widely consumed vegetables and an important part of an overall healthy diet. However, while millions of servings are consumed safely every day, leafy greens have been repeatedly associated with illnesses caused by Shiga toxin-producing E. coli (STEC), the most common of which is E. coli O157:H7. FDA is committed to breaking this cycle of reoccurring outbreaks.

Over the last several years the FDA and partners in the public and private sectors have worked to enhance the safety of leafy greens through the development and implementation of the Leafy Greens STEC Action Plan (LGAP). This work includes prioritized inspections, focused sampling, stakeholder engagement and collaboration, data sharing, root cause investigations, and advancements in the science of detection and prevention.

Collectively, this work has expanded our body of knowledge about how and why outbreaks linked to leafy greens have occurred, which has guided and informed the evolution of the action plan over the years. Still, we know that we cannot fix the issue of leafy green contamination on our own. Industry leadership, along with collaboration among growers, processors, retailers, state partners, and the broader agricultural community, is critical to establishing needed prevention measures and preventing foodborne illness.

The following table provides the approaches for three priority areas: Prevention, Response, and Addressing Knowledge Gaps, as well as accomplishments that have been made since the action plan launched in March 2020.

USA – FDA Core Table – Investigations of Foodborne Illness Outbreaks

FDA

What’s New

  • For the Salmonella Mississippi outbreak (ref# 1097) in a not yet identified product, the case count has increased from 99 to 100 cases.
  • For the Salmonella Senftenberg outbreak (ref# 1087) in a not yet identified food, the case count has increased from 22 to 27 cases.
  • For the Salmonella Typhimurium outbreak (ref# 1095) in a not yet identified food, the case count has increased from 73 to 78 cases.
  • For the Cyclospora outbreak (ref# 1080) the case count has increased from 75 to 79 cases.
  • For the Salmonella Braenderup outbreak (ref# 1075) the FDA investigation has closed. A product linked to illnesses was not identified.
  • The investigation associated with Dry Cereal (ref # 1064) has ended and the FDA investigation has closed with no pathogen or cause of the self-reported illnesses identified, despite extensive testing for numerous potential microbial and chemical adulterants.

RASFF Alerts – Animal Feed – Salmonella – Raw Pet Food – Whole Egg Powder

RASFF

Enterobacertiaceae and Salmonella spp. in raw pet food for fish from Thailand in Germany

RASFF

Salmonella spp. in whole egg powder, processed into pet- food from Germany in Switzerland and Austria

Research – Transmission of Cryptosporidium by Fresh Vegetables

Journal of Food Protection

water contamination

Consumption of fresh fruits and vegetables is increasing thanks to the awareness to the benefits to human health. Vegetables may become contaminated by enteric pathogens (protozoan parasites, bacteria and viruses) by irrigation with contaminated water, fertilization with fresh animal manure or by infected food handlers. Cryptosporidium spp. are fecal-oral protozoan parasites, known to be highly persistent in the environment, which facilitate the transmission of the infectious oocysts. Efficient methods were developed for releasing and concentrating Cryptosporidium oocysts from leafy vegetables and sensitive and specific methods were applied for their enumeration. The aims of this review are to discuss the development and optimization of methods applied to release oocysts from leafy vegetables, the prevalence of Cryptosporidium oocysts on fresh leafy vegetables from various parts of the world and to discuss cryptosporidiosis outbreaks resulting from the consumption of leafy vegetables. Three solutions were used with comparable efficiency to release oocysts from leafy vegetables 1M glycine solution, 0.1% Alconox and filter elution buffer with an efficiency of 36.2%, 72.6% and 44%, respectively. The prevalence of Cryptosporidium oocysts was reported in developed as well as from developing countries, although simple detection methods were applied. Most of the cryptosporidiosis outbreaks were reported in developed countries, which can be related to their efficient surveillance system. Transmission of infectious pathogens, such as Cryptosporidium may be facilitated by fresh vegetables, which are imported and transferred from less developed to highly developed countries and consumed uncooked. Monitoring of Cryptosporidium oocysts by sensitive detection methods may enhance measures to prevent their transmission by freshly consumed vegetables.

Research – Influence of Different Stainless-Steel Finishes on Biofilm Formation by Listeria monocytogenes

Journal of Food Protection

Biofilm formation of L. monocytogenes on stainless steel, a widely used abiotic surface in the food processing industry was investigated, focusing on the attachment tendency and behavior of L. monocytogenes 08-5578 on eight different Stainless-steel surfaces: glass bead blasted (rough and fine), deburred (Timesaver), drum deburred, pickled, pickled and drum polished, electrolytic polished and cold rolled (untreated control). The aim was to see if there are finishes with significant lower bacterial attachment. Roughness properties (Ra, Rt, Rz, RSm; determined by interferometry) were also compared with number of adhering cells to detect possible correlations. Cultivation of L. monocytogenes biofilms was carried out using a CDC biofilm reactor (CBR) with 1% TSB set at 20°C for 4, 8, and 24 h. Additionally, a cultivation trial was run with continuous nutrient flow (1% TSB, 6.2 ml/min) for 24 h. Eight hour results showed significant difference ( P < 0.05) in biofilm cell counts in biofilms between the glass bead blasted surfaces (3.23 and 3.26 log CFU/cm 2 for the fine and rough, respectively) and deburred (Timesaver) surface (2.57 log CFU/cm 2 ); between drum deburred and deburred (Timesaver) surface (3.41 vs 2.57 log CFU/cm 2 ); between drum deburred and pickled surface (3.41 vs 2.77 log CFU/cm 2 ). Data gained after 4, 24 h and the additional 24 h continuous flow cultivation showed no significant difference in attachment among surfaces. No correlation between roughness data and attachment was found after all 4 incubation times, suggesting that roughness values, at these ranges, are insufficient in determining surfaces’ affinity to bacteria. This study suggests that roughness values cannot be used to predict the degree of L. monocytogenes attachment to a specific stainless steel surface.

Research – Incidence of Food Poisoning Outbreaks in Pahang, Malaysia, for Six-Year, from 2013 to 2018

Pertanika

The Food Safety and Quality Division (FSQD) in Malaysia is the competent authority tasked with ensuring food safety throughout the food supply chain within the country. Despite implementing various regulations toward improving food hygiene standards in Malaysia, outbreaks of food poisoning cases continued to occur in Malaysia. This cross-sectional study was designed to explore the occurrence of food poisoning incidents in Malaysia, within the Pahang state, from 2013 to 2018 via both reported passive case detection (PCD) and active case detection (ACD) food poisoning incidents. Upon detecting all the food poisoning cases using both PCD and ACD, the people identified to have suffered from food poisoning underwent a structured interview for investigators to elicit all relevant information about the food poisoning incident. Results showed that in Pahang, the number of reported episodes fluctuated from 2013 until 2018, with an average of 21 food poisoning episodes occurring yearly, reaching a maximum in August and a minimum in May. Furthermore, Kuantan, being the state capital, had reported an exceptionally high total number of reported incidents of food poisoning with a total of 48 episodes over six years from 2013 to 2018, while Kuala Lipis had only one incident reported during the same period (which was reported in 2016). Finally, this study concluded that adequate measures must always be taken to minimise the occurrence of food poisoning, especially when preparing foods in large quantities.

Research – USA – Summary of Possible Multistate Enteric (Intestinal) Disease Outbreaks in 2017–2020

CDC

This analysis includes 470 possible multistate outbreak investigations during 2017–2020.

Research – Examining Patterns of Persistent Listeria Contamination in Packinghouses using Agent-Based Models

Journal of Food Protection

Persistent Listeria monocytogenes contamination may occur in a packinghouse if the pathogen successfully infiltrates the facility and reaches a harborage site, from where it is difficult to remove and may contaminate produce within the facility. There is a need for simulation-based decision support tools that can predict which equipment sites are more likely to undergo persistent contamination and simulate potential corrective actions to prevent persistent contamination. Thus, we adapted for longer term simulation two existing applications of an agent-based model of Listeria spp. hourly contamination dynamics in produce packinghouses. Next, we developed a novel approach to identify and analyze persistent and transient Listeria contamination patterns on simulated agents representing equipment sites and employees. Testing of corrective actions showed that methods that involved targeted, facility-specific, risk-based sanitation were the most effective in both reducing the likelihood and duration of persistent contamination. This emphasizes that generic approaches to controlling Listeria (e.g., more concentrated sanitizers) are unlikely to be successful and suggests that usage of sanitation schedules produced through facility-specific root-cause analysis and hygienic design are key in reducing persistence. Hourly Listeria contamination patterns also suggest that transient contamination may be mistaken for persistent, depending on the frequency of environmental sampling. Likewise, as concentrations of Listeria on most contaminated agents were predicted to be very low, there is also a possibility to mistake persistence for transient contamination of sites, or even miss it outright due to false negative environmental Listeria monitoring results. These findings support that agent-based models may be valuable decision-support tools, aiding in the identification of contamination patterns within packinghouses and assessing the viability of specific corrective actions.

Research – Notes from the Field: Outbreak of Salmonella Enteritidis at a Correctional Facility Using Mechanically Separated Chicken — Nebraska, 2022

CDC

On January 14, 2022, the Lincoln-Lancaster County (Nebraska) Health Department (LLCHD) notified the Nebraska Department of Health and Human Services (NDHHS) of two cases of laboratory-confirmed Salmonella in inmates at a correctional facility (facility A). LLCHD initiated an investigation in collaboration with NDHHS to identify the source of the outbreak and develop recommendations. The investigation linked consumption of mechanically separated chicken to illness. Mechanically separated chicken, which is produced at chicken processing facilities by separating edible chicken from bone and cartilage under pressure, is frequently purchased for use in institutions, such as prisons, jails, and correctional facilities because of its affordability (1,2).

Staff members at facility A reported approximately 100 inmates experienced gastrointestinal symptoms during a period of a few days; no staff member reported illness. LLCHD conducted open-ended interviews with ill inmates. Because the facility was experiencing a concurrent outbreak of COVID-19, and access to inmates for interviews was limited, it is likely that additional cases existed among noninterviewed and untested inmates beyond the total cases identified in the investigation. Inmates who were designated food handlers were prioritized for interviews because of transmission risk to others; untested inmates were able to seek care through facility A medical staff. A probable case was defined as the onset of diarrhea, stomach cramps, or vomiting during January 9–11, 2022, but without a positive stool culture, in an inmate at facility A; a confirmed case was defined as isolation of Salmonella serotype Enteritidis highly related to the outbreak strain (within three alleles) by core genome multilocus sequence typing in a clinical specimen. LLCHD conducted an environmental assessment on January 15, 2022. A list of food handlers, food menus for January, and temperature logs were requested. During the environmental assessment, a sample of raw, unopened mechanically separated chicken from a 50-lb intact box from the same shipment used to prepare a meal on January 8, 2022, was collected for testing.

A total of 15 cases of S. Enteritidis infection were identifie

Research – Outbreak Investigation of E. coli O157:H7: Unknown Food (Fall 2020)

Food Poisoning News

The FDA and CDC, in collaboration with state and local partners, have completed the investigation on two of three multistate outbreak of E. coli O157:H7 infections in the U.S. this fall.

One of these investigations, Outbreak Unknown Source 3, identified 18 reported illnesses in nine states: California, Colorado, Illinois, Michigan, New York, Ohio, Pennsylvania, Virginia, Washington.

FDA completed a traceback investigation of several potential food vehicles identified in patient interviews and although no single farm was identified as a common source of the outbreak, FDA and state partners also conducted on-site investigations on farms of interest. However, information and samples collected in these inspections did not link these farms to the outbreak. The investigation of a farm does not mean that the farm is linked to an outbreak. The results of an investigation into a farm may well lead to that firm being ruled out of the investigation. On 12/18/2020, the CDC announced that this outbreak had ended.

The other completed outbreak investigation, Outbreak Unknown Source 1, identified 32 reported illnesses in 12 states: California, Illinois, Louisiana, Maryland, Michigan, Montana, New Jersey, Ohio, Utah, Virginia, Washington, Wisconsin. This strain of E. coli is genetically similar to a strain linked to a romaine outbreak that occurred in the spring of 2018, though a food was not linked to the current outbreak. FDA completed a traceback investigation and was unable to determine a common source of the outbreak. FDA and state partners also conducted on-site inspections on farms of interest, though information collected in these inspections did not link these farms to the outbreak. On 12/18/2020, the CDC announced that this outbreak had ended.

Investigations of a third E. coli outbreak of Unknown Source 2 continue.