Shiga Toxin-Producing Escherichia coli Infections Associated With Romaine Lettuce-United States, 2018.

BACKGROUND: Produce-associated outbreaks of Shiga toxin-producing Escherichia coli (STEC) were first identified in 1991. In April 2018, New Jersey and Pennsylvania officials reported a cluster of STEC O157 infections associated with multiple locations of a restaurant chain. The Centers for Disease Control and Prevention (CDC) queried PulseNet, the national laboratory network for foodborne disease surveillance, for additional cases and began a national investigation. METHODS: A case was defined as an infection between 13 March and 22 August 2018 with 1 of the 22 identified outbreak-associated E. coli O157:H7 or E. coli O61 pulsed-field gel electrophoresis pattern combinations, or with a strain STEC O157 that was closely related to the main outbreak strain by whole-genome sequencing. We conducted epidemiologic and traceback investigations to identify illness subclusters and common sources. A US Food and Drug Administration-led environmental assessment, which tested water, soil, manure, compost, and scat samples, was conducted to evaluate potential sources of STEC contamination. RESULTS: We identified 240 case-patients from 37 states; 104 were hospitalized, 28 developed hemolytic uremic syndrome, and 5 died. Of 179 people who were interviewed, 152 (85%) reported consuming romaine lettuce in the week before illness onset. Twenty subclusters were identified. Product traceback from subcluster restaurants identified numerous romaine lettuce distributors and growers; all lettuce originated from the Yuma growing region. Water samples collected from an irrigation canal in the region yielded the outbreak strain of STEC O157. CONCLUSIONS: We report on the largest multistate leafy greens-linked STEC O157 outbreak in several decades. The investigation highlights the complexities associated with investigating outbreaks involving widespread environmental contamination.

Multistate Outbreak of Salmonella Virchow Infections Linked to a Powdered Meal Replacement Product-United States, 2015-2016.

Background: Nontyphoidal Salmonella is the leading cause of bacterial gastroenteritis in the United States. Meal replacement products containing raw and "superfood" ingredients have gained increasing popularity among consumers in recent years. In January 2016, we investigated a multistate outbreak of infections with a novel strain of Salmonella Virchow. Methods: Cases were defined using molecular subtyping procedures. Commonly reported exposures were compared with responses from healthy people interviewed in the 2006-2007 FoodNet Population Survey. Firm inspections and product traceback and testing were performed. Results: Thirty-five cases from 24 states were identified; 6 hospitalizations and no deaths were reported. Thirty-one of 33 (94%) ill people interviewed reported consuming a powdered supplement in the week before illness; of these, 30 (97%) reported consuming product A, a raw organic powdered shake product consumed as a meal replacement. Laboratory testing isolated the outbreak strain of Salmonella Virchow from leftover product A collected from ill people's homes, organic moringa leaf powder (an ingredient in product A), and finished product retained by the firm. Firm inspections at 3 facilities linked to product A production did not reveal contamination at the facilities. Traceback investigation identified that the contaminated moringa leaf powder was imported from South Africa. Conclusions: This investigation identified a novel outbreak vehicle and highlighted the potential risk with similar products not intended to be cooked by consumers before consuming. The company issued a voluntary recall of all implicated products. As this product has a long shelf life, the recall likely prevented additional illnesses.

Multistate Outbreak of Salmonella Anatum Infections Linked to Imported Hot Peppers - United States, May-July 2016.

Foodborne salmonellosis causes an estimated 1 million illnesses and 400 deaths annually in the United States (1). Salmonella Anatum is one of the top 20 Salmonella serotypes in the United States. During 2013-2015 there were approximately 300-350 annual illnesses reported to PulseNet, the national molecular subtyping network for foodborne disease surveillance. In June 2016, PulseNet identified a cluster of 16 Salmonella Anatum infections with an indistinguishable pulsed-field gel electrophoresis (PFGE) pattern from four states.* In April 2016, the same PFGE pattern had been uploaded to PulseNet from an isolate obtained from an Anaheim pepper, a mild to medium hot pepper. Hot peppers include many pepper varieties, such as Anaheim, jalapeño, poblano, and serrano, which can vary in heat level from mild to very hot depending on the variety and preparation. This rare PFGE pattern had been seen only 24 times previously in the PulseNet database, compared with common PFGE patterns for this serotype which have been seen in the database hundreds of times. Local and state health departments, CDC, and the Food and Drug Administration (FDA) investigated to determine the cause of the outbreak. Thirty-two patients in nine states were identified with illness onsets from May 6-July 9, 2016. Whole-genome sequencing (WGS) was performed to characterize clinical isolates and the Anaheim pepper isolate further. The combined evidence indicated that fresh hot peppers were the likely source of infection; however, a single pepper type or source farm was not identified. This outbreak highlights challenges in reconciling epidemiologic and WGS data, and the difficulties of identifying ingredient-level exposures through epidemiologic investigations alone.

Multinational Outbreak of Listeria monocytogenes Infections Linked to Enoki Mushrooms Imported from the Republic of Korea 2016-2020.

Keeping the global food supply safe necessitates international collaborations between countries. Health and regulatory agencies routinely communicate during foodborne illness outbreaks, allowing partners to share investigational evidence. A 2016-2020 outbreak of Listeria monocytogenes infections linked to imported enoki mushrooms required a multinational collaborative investigation among the United States, Canada, Australia, and France. Ultimately, this outbreak included 48 ill people, 36 in the United States and 12 in Canada, and was linked to enoki mushrooms sourced from one manufacturer located in the Republic of Korea. Epidemiologic, laboratory, and traceback evidence led to multiple regulatory actions, including extensive voluntary recalls by three firms in the United States and one firm in Canada. In the United States and Canada, the Korean manufacturer was placed on import alert while other international partners provided information about their respective investigations and advised the public not to eat the recalled enoki mushrooms. The breadth of the geographic distribution of this outbreak emphasizes the global reach of the food industry. This investigation provides a powerful example of the impact of national and international coordination of efforts to respond to foodborne illness outbreaks and protect consumers. It also demonstrates the importance of fast international data sharing and collaboration in identifying and stopping foodborne outbreaks in the global community. Additionally, it is a meaningful example of the importance of food sampling, testing, and integration of sequencing results into surveillance databases.

An Outbreak Investigation of Scombrotoxin Fish Poisoning Illnesses in the United States Linked to Yellowfin Tuna Imported from Vietnam-2019.

ABSTRACT: Scombrotoxin fish poisoning (SFP) is caused by the ingestion of certain fish species with elevated concentrations of histamine due to decomposition. In fall 2019, the U.S. Food and Drug Administration (FDA) was notified of 51 SFP cases including two hospitalizations from 11 states through the FDA consumer complaint system or directly from state partners. A case patient was defined as an individual who experienced a histamine-type reaction after consumption of tuna imported from Vietnam and an illness onset between 14 August and 24 November 2019. A traceback investigation was initiated at 19 points of service to identify a common tuna source. The FDA and state partners collected 34 product samples throughout the distribution chain, including from a case patient's home, points of service, distributors, and the port of entry. Samples were analyzed for histamine by sensory evaluation and/or chemical testing. Case patients reported exposure to tuna imported from Vietnam. The traceback investigation identified two Vietnamese manufacturers as the sources of the tuna. Twenty-nine samples were confirmed as decomposed by sensory evaluation and/or were positive for elevated histamine concentrations by chemical testing. Both Vietnamese companies were placed on an import alert. Seven U.S. companies and one Vietnamese company initiated voluntary recalls. The FDA released public communication naming the U.S. importers to help suppliers and distributors identify the product and effectuate the foreign company's recall. This SFP outbreak investigation highlights the complexities of the federal outbreak response, specifically related to imported food. Cultural considerations regarding imported foods should be addressed during outbreak responses when timing is critical. Collaboration with countries where confidentiality agreements are not in place can limit information sharing and the speed of public health responses.

Effect of electron beam on chemical changes of nutrients in infant formula.

Infant milk formula has recently been implicated as a transmission vehicle for an emerging foodborne pathogen, Enterobacter sakazakii, resulting in high mortality rates. Electron beam (e-beam) efficiently and non-thermally inactivates foodborne pathogens, including E. sakazakii, in infant milk formula. However, the effects of e-beam on chemical changes of nutrients in infant formula have not been determined. Therefore, the objective of this study was to fulfill this gap. Dehydrated infant milk formula was processed with e-beam at 0 (control) to 25 kGy. Amino acid, fatty acid, and mineral profiles (AAP, FAP, and MP, respectively), as well as protein degradation and lipid oxidation, were determined. There were no differences (P>0.05) in FAP, AAP, and MP. SDS-PAGE electrophoresis qualitatively detected three major protein bands in all samples up to 25 kGy. Densitometry analysis of SDS-PAGE gels confirmed no size degradation (P>0.05) as a function of increased e-beam dose. Totol-volatile-basic-nitrogen (TVBN) excluded (P>0.05) protein degradation due to microbial activity. There was no increase (P>0.05) in lipid oxidation, as assessed with thiobarbituric-reactive-substances (TBARS), except in samples processed at 25 kGy. Dehydrated formula has low water activity, which likely protected nutrients from e-beam-induced chemical changes. This study demonstrates that proteins, lipids, and minerals in infant milk formula are stable when processed with e-beam up to 25 kGy at low temperature and under anaerobic conditions.

Radioresistance development of DNA repair deficient Escherichia coli DH5α in ground beef subjected to electron beam at sub-lethal doses.

PURPOSE: Electron beam (e-beam) efficiently and non-thermally inactivates microorganisms in food by lethal DNA changes (direct effects) and free radicals from water radiolysis (in-direct effects). Non-pathogenic Escherichia coli DH5α (α substrain of DH5 described by Hanahan 1985 , 'DH' stands for Douglas Hanahan) is a microorganism that lacks DNA repair capability, resulting in high radiosensitivity. Studying microbial inactivation of E. coli DH5α repeatedly subjected to sub-lethal e-beam in ground beef may enhance understanding of microbial radioresistance. The objective of this study was to determine if repetitive processing with e-beam at sub-lethal doses increases D-value (e-beam dose required to inactivate one log of microbial population) of E. coli DH5α in ground beef. MATERIALS AND METHODS: Survivors from the highest e-beam dose were isolated and incubated in ground beef for the next cycle of e-beam processing. Five cycles were conducted. To acclimatise E. coli DH5α, first two cycles used low doses. D-values were determined following the third cycle. RESULTS: D-values increased (p < 0.05) significantly with each cycle. Thus, E. coli DH5α has a capability to develop greater radioresistance under these experimental conditions. Following the third cycle D-values were 0.32 ±â€Š0.006 and 0.32 ±â€Š0.002 kGy for survivors enumerated on non-selective and selective media, respectively; the fourth cycle 0.39 ±â€Š0.007 and 0.40 ±â€Š0.019 kGy; and the fifth cycle 0.46 ±â€Š0.006 and 0.46 ±â€Š0.020 kGy. D-values on non-selective and selective media were similar (p > 0.05) indicating absence of cell recovery in E. coli DH5α. CONCLUSIONS: E. coli DH5α increases radioresistance to e-beam as a result of repetitive exposure to sub-lethal doses despite its DNA repair deficiency.