2015 Salmonella Outbreak Linked to Imported Cucumbers

Posted March 18, 2016 2:30 PM ET

This outbreak appears to be over. However, Salmonella remains an important cause of human illness in the United States. For more information about Salmonella and steps that people can take to reduce their risk of infection, visit CDC’s Salmonella webpage.

Highlights

This outbreak appears to be over. However, Salmonella remains an important cause of human illness in the United States. For more information about Salmonella and steps that people can take to reduce their risk of infection, visit CDC’s Salmonella webpage.
CDC, multiple states, and the U.S. Food and Drug Administration (FDA) investigated a multistate outbreak of Salmonella Poona infections.
- A total of 907 people infected with the outbreak strains of Salmonella Poona were reported from 40 states.
- A total of 204 ill people were hospitalized, and six deaths were reported from Arizona (1), California (3), Oklahoma (1), and Texas (1). Salmonella infection was not considered to be a contributing factor in two of the three deaths in California.
Epidemiologic, laboratory, and traceback investigations identified cucumbers imported from Mexico and distributed by Andrew & Williamson Fresh Produce as the likely source of the infections in this outbreak.
Two recalls of cucumbers that may be contaminated with Salmonella were announced in September 2015 as a result of this investigation: Andrew & Williamson Fresh Produce and Custom Produce Sales.
Investigation of illnesses that were reported after the peak of the outbreak in August and September 2015 did not identify an additional food linked to illness. The source of contamination for the cucumbers distributed by Andrew & Williamson Fresh Produce has not been identified.

Outbreak Summary

Introduction

CDC collaborated with public health officials in many states and the U.S. Food and Drug Administration (FDA) to investigate a multistate outbreak of Salmonella Poona infections.

Public health investigators used the PulseNet system to identify illnesses that were part of this outbreak. PulseNet, coordinated by CDC, is the national subtyping network of public health and food regulatory agency laboratories. PulseNet performs DNA fingerprinting on Salmonella bacteria isolated from ill people by using techniques called pulsed-field gel electrophoresis (PFGE) and whole genome sequencing (WGS). CDC PulseNet manages a national database of these DNA fingerprints to identify possible outbreaks.

A total of 907 people infected with the outbreak strains of Salmonella Poona were reported from 40 states. A list of states and the number of cases in each can be found on the Case Count Map page.

Among people for whom information was available, illnesses started on dates ranging from July 3, 2015 to February 29, 2016. Ill people ranged in age from less than 1 year to 99, with a median age of 18. Forty-nine percent of ill people were children younger than 18 years. Fifty-six percent of ill people were female. Among 720 people with available information, 204 (28%) were hospitalized. Six deaths were reported from Arizona (1), California (3), Oklahoma (1), and Texas (1). According to the California Department of Public Health, Salmonella infection was not considered to be a contributing factor in two of the three deaths in California.

WGS showed that isolates from ill people were closely related genetically. These results also included isolates from people who became ill in October, November and January after the outbreak’s peak. This close genetic relationship means that people in this outbreak were more likely to share a common source of infection, such as a contaminated food.

Investigation of the Outbreak

Epidemiologic, laboratory, and traceback investigations identified imported cucumbers from Mexico and distributed by Andrew & Williamson Fresh Produce as the likely source of the infections in this outbreak.

Epidemiologic Investigation

State and local public health officials interviewed ill people to obtain information about foods they might have eaten and other exposures in the week before their illness began. In interviews, 391 (75%) of 519 people reported eating cucumbers. This proportion was significantly higher than results from a survey of healthy people [PDF – 29 pages] in which 47% reported eating cucumbers in the week before they were interviewed.

Also, many ill people were identified as part of illness clusters. An illness cluster is defined as two or more people who do not live in the same household who report eating at the same restaurant location, attending a common event, or shopping at the same location of a grocery store in the week before becoming ill. Investigating illness clusters can provide critical clues about the source of an outbreak. If several unrelated ill persons ate or shopped at the same location of a restaurant or store within several days of each other, it suggests that the contaminated food item was served or sold there. Eleven illness clusters were identified in seven states. In all of these clusters, interviews found that cucumbers were a common item eaten by ill people. Epidemiologic studies that compare foods eaten by both ill and well people were conducted in two of these clusters. Results of these studies indicated that a food item containing cucumbers was associated with illness.

CDC’s National Antimicrobial Resistance Monitoring System (NARMS) laboratory conducted antibiotic resistance testing on clinical isolates collected from 30 ill people infected with one of the outbreak strains. Of the 30 isolates tested, 2 (7%) were drug resistant (resistance to one or more antibiotics), and the other 28 (93%) isolates were not resistant to any of the antibiotics tested by NARMS. One drug-resistant isolate was resistant to tetracycline. The other isolate was resistant to nalidixic acid and nonsusceptible to ciprofloxacin. Nonsusceptible means an antibiotic cannot completely kill bacteria or stop their growth. Ciprofloxacin is commonly used to treat serious Salmonella infections in adults but is not routinely used in children. Antibiotic resistance may be associated with increased risk of hospitalization, development of a bloodstream infection, or treatment failure.

Laboratory Investigation

Several state health and agriculture departments collected and tested cucumbers from retail locations and isolated the outbreak strains of Salmonella Poona. Information indicated that these cucumbers were distributed by Andrew & Williamson Fresh Produce. Additionally, testing of cucumbers collected from the Andrew & Williamson Fresh Produce facility isolated the outbreak strains of Salmonella Poona.

WGS of Salmonella Poona isolates from ill people and from contaminated cucumbers distributed by Andrew & Williamson Fresh Produce showed that the strains were closely related genetically. This close genetic relationship provided additional evidence that ill people in this outbreak became ill from consuming cucumbers distributed by Andrew & Williamson.

Traceback and Regulatory Investigation

Early in an outbreak investigation, consultation with independent industry experts can provide important clues to help focus the investigation on certain suspected foods. An industry consultation was held on August 26, 2015, with four independent experts from the produce industry to obtain information regarding fresh produce harvesting and distribution in the areas where ill people were being reported. The consultants provided information regarding crop production and distribution practices that helped assess the plausibility of cucumbers and other produce items as possible outbreak sources.

Traceback information collected from the 11 illness clusters indicated that cucumbers eaten by ill people were imported from Mexico and distributed by Andrew & Williamson Fresh Produce.

Two recalls of garden variety cucumbers distributed by Andrew & Williamson Fresh Produce were announced because the cucumbers were likely contaminated with Salmonella. Recalled cucumbers were grown in Baja California, Mexico and distributed to many U.S. states. On September 4, 2015, Andrew & Williamson Fresh Produce voluntarily recalled all cucumbers sold under the Limited Edition brand label from August 1, 2015 through September 3, 2015. On September 11, 2015, Custom Produce Sales voluntarily recalled all cucumbers sold under the Fat Boy brand label starting August 1, 2015. These cucumbers were sent to Custom Produce Sales from Andrew & Williamson Fresh Produce.

Illnesses Occurring after September 24, 2015

The number of reported illnesses declined substantially after the peak of illnesses in August and September; however, illnesses did not return to the expected number for several months afterwards for this DNA fingerprint (typically, about one illness is expected every month from November through January). Instead, 127 illnesses started after September 24, 2015, when recalled cucumbers should have no longer been available in stores or restaurants. If any of the recalled cucumbers were still available, they would have spoiled by that time.

WGS results from illnesses which occurred after the end of September 2015 suggested they shared a common source with the illnesses during the peak of the outbreak in August and September. State and local public health officials interviewed 46 of these ill people. Of that group, 29 (63%) reported eating cucumbers in the week before their illness started. Interviews did not identify any additional food items potentially linked with illness. Investigations were unable to determine if the illnesses could be explained by cross-contamination within the distribution chain for the recalled cucumbers, such as in shipping containers or at retail locations. This outbreak appears to be over.

At A Glance

Case Count: 907
States: 40
Deaths: 6
Hospitalizations: 204
Recall: Yes

CLICK TO VIEW EPI CURVE GRAPHS

Epi Curve Multisate Salmonella outbreak for Imported Cucumbers - Poona

CLICK TO VIEW CASE COUNT MAPS

Map of Salmonella Imported Cucumber Outbreak

image of a cucumber half sliced with a white background

Garden cucumber

Final Case Count Update

This outbreak appears to be over. Since the last update on January 26, 2016, 19 more ill people were reported from eight states.

A total of 907 people infected with the outbreak strains of Salmonella Poona were reported from 40 states. A list of states and the number of cases in each can be found on the Case Count Map page.

Case Count Update

Since the last update on November 19, 2015, 50 more ill people have been reported from 16 states. Illnesses that occurred after December 21, 2015 might not be reported yet. A series of events occurs between the time a person is infected and the time public health officials can determine that the person is part of an outbreak. This means that there will be a delay between when a person gets sick and confirmation that he or she is part of an outbreak. This takes an average of 2 to 4 weeks. Please see the Timeline for Reporting Cases of Salmonella Infection for more details.

As of January 21, 2016, 888 people infected with the outbreak strains of Salmonella Poona have been reported from 39 states. The number of ill people reported from each state is as follows: Alabama (1), Alaska (19), Arizona (134), Arkansas (13), California (241), Colorado (21), Connecticut (1), Florida (1), Hawaii (1), Idaho (26), Illinois (11), Indiana (5), Iowa (7), Kansas (2), Kentucky (1), Louisiana (5), Maryland (1), Minnesota (43), Missouri (15), Montana (16), Nebraska (8), Nevada (17), New Hampshire (1), New Mexico (35), New York (6), North Dakota (8), Ohio (3), Oklahoma (13), Oregon (23), Pennsylvania (2), South Carolina (10), South Dakota (3), Tennessee (1), Texas (52), Utah (62), Virginia (1), Washington (26), Wisconsin (46), and Wyoming (7).

Among people for whom information is available, illnesses started on dates ranging from July 3, 2015 to January 6, 2016. Ill people range in age from less than 1 year to 99, with a median age of 18. Forty-nine percent of ill people are children younger than 18 years. Fifty-six percent of ill people are female. Among 686 people with available information, 191 (28%) report being hospitalized. Six deaths have been reported from Arizona (1), California (3), Oklahoma (1), and Texas (1). According to the California Department of Public Health, Salmonella infection was not considered to be a contributing factor in two of the three deaths in California.

Investigation Update

Whole genome sequencing (WGS) of Salmonella Poona isolates from ill people and from contaminated cucumbers distributed by Andrew & Williamson Fresh Produce showed that the strains are closely related genetically. These results also included isolates from people who became ill in October and November.

The number of reported illnesses has declined substantially since the peak of illnesses in August and September; however, it has not returned to the number of reported illnesses that we would expect to see (about 1 every month during this time of year).

One hundred and six illnesses started after September 24, 2015, when recalled cucumbers should have no longer been available in stores or restaurants. If any of the recalled cucumbers were still available, they would have spoiled by that time. State and local public health officials have interviewed 38 of these ill people. Twenty-four (63%) of them reported eating cucumbers in the week before their illness started. Interviews have not identified any additional food items potentially linked with illness. The investigation into the source of these recent illnesses is ongoing.

The source of contamination for cucumbers distributed by Andrew & Williamson Fresh Produce has not been identified. WGS results from recent illnesses suggest they share a common source with the illnesses during the peak of the outbreak in August and September. Investigations are under way to determine if cross-contamination within the distribution chain for the recalled cucumbers could explain recent illnesses.

This investigation is ongoing. CDC will provide updates when more information is available.

Case Count Update

Since the last update on October 14, 2015, 71 more ill people have been reported from 23 states. Illnesses that occurred after October 21, 2015 might not be reported yet. A series of events occurs between the time a person is infected and the time public health officials can determine that the person is part of an outbreak. This means that there will be a delay between when a person gets sick and confirmation that he or she is part of an outbreak. This takes an average of 2 to 4 weeks. Please see the Timeline for Reporting Cases of Salmonella Infection for more details.

As of November 18, 2015, 838 people infected with the outbreak strains of Salmonella Poona have been reported from 38 states. The number of ill people reported from each state is as follows: Alabama (1), Alaska (17), Arizona (129), Arkansas (13), California (232), Colorado (19), Connecticut (1), Florida (1), Hawaii (1), Idaho (24), Illinois (9), Indiana (5), Iowa (7), Kansas (2), Kentucky (1), Louisiana (5), Maryland (1), Minnesota (40), Missouri (14), Montana (16), Nebraska (8), Nevada (16), New Hampshire (1), New Mexico (32), New York (6), North Dakota (8), Ohio (3), Oklahoma (13), Oregon (22), Pennsylvania (2), South Carolina (10), South Dakota (3), Texas (42), Utah (58), Virginia (1), Washington (25), Wisconsin (43), and Wyoming (7).

Among people for whom information is available, illnesses started on dates ranging from July 3, 2015 to November 1, 2015. Ill people range in age from less than 1 year to 99, with a median age of 18. Fifty percent of ill people are children younger than 18 years. Fifty-seven percent of ill people are female. Among 601 people with available information, 165 (27%) report being hospitalized. Four deaths have been reported from Arizona (1), California (1), Oklahoma (1), and Texas (1).

Case Count Update

Since the last update on October 6, 2015, 35 more ill people have been reported from 14 states. Illnesses that occurred after September 15, 2015 might not be reported yet. A series of events occurs between the time a person is infected and the time public health officials can determine that the person is part of an outbreak. This means that there will be a delay between when a person gets sick and confirmation that he or she is part of an outbreak. This takes an average of 2 to 4 weeks. Please see the Timeline for Reporting Cases of Salmonella Infection for more details. Also, cucumbers have a shelf life of up to 14 days. Some people may not have known about the recall and eaten the contaminated cucumbers after the recall.

As of October 13, 2015, 767 people infected with the outbreak strains of Salmonella Poona have been reported from 36 states. The number of ill people reported from each state is as follows: Alabama (1), Alaska (16), Arizona (118), Arkansas (11), California (205), Colorado (18), Florida (1), Hawaii (1), Idaho (24), Illinois (9), Indiana (4), Iowa (6), Kansas (2), Kentucky (1), Louisiana (5), Maryland (1), Minnesota (38), Missouri (12), Montana (15), Nebraska (7), Nevada (14), New Mexico (31), New York (6), North Dakota (6), Ohio (3), Oklahoma (12), Oregon (21), Pennsylvania (2), South Carolina (9), South Dakota (3), Texas (38), Utah (53), Virginia (1), Washington (24), Wisconsin (42), and Wyoming (7).

Among people for whom information is available, illnesses started on dates ranging from July 3, 2015 to September 29, 2015. Ill people range in age from less than 1 year to 99, with a median age of 17. Fifty percent of ill people are children younger than 18 years. Fifty-five percent of ill people are female. Among 561 people with available information, 157 (28%) report being hospitalized. Four deaths have been reported from Arizona (1), California (1), Oklahoma (1), and Texas (1).

Case Count Update

Since the last update on September 29, 2015, 61 new ill people have been reported from 24 states. It can take up to a week from the time people eat food contaminated with Salmonella before they get sick. Also, cucumbers have a shelf life of up to 14 days. It is not unexpected to continue to see illnesses reported after the recalls. Some people may not have known about the recall and eaten the contaminated cucumbers after the recall.

As of October 5, 2015, 732 people infected with the outbreak strains of Salmonella Poona have been reported from 35 states. The number of ill people reported from each state is as follows: Alabama (1), Alaska (14), Arizona (114), Arkansas (11), California (192), Colorado (18), Hawaii (1), Idaho (24), Illinois (9), Indiana (3), Iowa (6), Kansas (2), Kentucky (1), Louisiana (5), Maryland (1), Minnesota (37), Missouri (11), Montana (14), Nebraska (6), Nevada (14), New Mexico (31), New York (6), North Dakota (6), Ohio (2), Oklahoma (12), Oregon (20), Pennsylvania (2), South Carolina (9), South Dakota (3), Texas (34), Utah (53), Virginia (1), Washington (22), Wisconsin (40), and Wyoming (7).

Among people for whom information is available, illnesses started on dates ranging from July 3, 2015 to September 25, 2015. Ill people range in age from less than 1 year to 99, with a median age of 17. Fifty percent of ill people are children younger than 18 years. Fifty-five percent of ill people are female. Among 536 people with available information, 150 (28%) report being hospitalized. Four deaths have been reported from Arizona (1), California (1), Oklahoma (1), and Texas (1).
Illnesses that occurred after September 8, 2015 might not be reported yet. A series of events occurs between the time a person is infected and the time public health officials can determine that the person is part of an outbreak. This means that there will be a delay between when a person gets sick and confirmation that he or she is part of an outbreak. This takes an average of 2 to 4 weeks. Please see the Timeline for Reporting Cases of Salmonella Infection for more details.

Case Count Update

Since the last update on September 22, 2015, 113 new ill people have been reported from 19 states. It can take up to a week from the time people eat food contaminated with Salmonella before they get sick. Also, cucumbers have a shelf life of up to 14 days. It is not unexpected to continue to see illnesses reported after the recalls. Some people may not have known about the recall and eaten the contaminated cucumbers after the recall.

As of September 28, 2015, 671 people infected with the outbreak strains of Salmonella Poona have been reported from 34 states. The number of ill people reported from each state is as follows: Alabama (1), Alaska (13), Arizona (112), Arkansas (9), California (164), Colorado (17), Hawaii (1), Idaho (22), Illinois (8), Indiana (2), Iowa (5), Kansas (2), Kentucky (1), Louisiana (5), Minnesota (34), Missouri (10), Montana (14), Nebraska (5), Nevada (13), New Mexico (30), New York (5), North Dakota (3), Ohio (2), Oklahoma (12), Oregon (19), Pennsylvania (2), South Carolina (9), South Dakota (1), Texas (33), Utah (51), Virginia (1), Washington (21), Wisconsin (38), and Wyoming (6).

Among people for whom information is available, illnesses started on dates ranging from July 3, 2015 to September 21, 2015. Ill people range in age from less than 1 year to 99, with a median age of 17. Fifty-one percent of ill people are children younger than 18 years. Fifty-four percent of ill people are female. Among 459 people with available information, 131 (29%) report being hospitalized. Three deaths have been reported from Arizona (1), California (1) and Texas (1).

Illnesses that occurred after September 2, 2015 might not be reported yet. A series of events occurs between the time a person is infected and the time public health officials can determine that the person is part of an outbreak. This means that there will be a delay between when a person gets sick and confirmation that he or she is part of an outbreak. This takes an average of 2 to 4 weeks. Please see the Timeline for Reporting Cases of Salmonella Infection for more details.

Case Count Update

Since the last update on September 15, 2015, 140 new ill people have been reported from Alaska (2), Arizona (23), Arkansas (2), California (31), Colorado (1), Idaho (6), Illinois (2), Iowa (1), Kansas (1), Minnesota (9), Missouri (1), Montana (1), Nebraska (3), Nevada (2), New Mexico (5), New York (1), North Dakota (1), Oklahoma (2), Oregon (9), South Dakota (1), Texas (4), Utah (9), Washington (3), and Wisconsin (20).

As of September 21, 2015, a total of 558 people infected with the outbreak strains of Salmonella Poona have been reported from 33 states. The number of ill people reported from each state is as follows: Alaska (12), Arizona (95), Arkansas (8), California (120), Colorado (17), Hawaii (1), Idaho (20), Illinois (8), Indiana (2), Iowa (1), Kansas (2), Kentucky (1), Louisiana (4), Minnesota (29), Missouri (9), Montana (14), Nebraska (5), Nevada (11), New Mexico (27), New York (5), North Dakota (3), Ohio (2), Oklahoma (12), Oregon (17), Pennsylvania (2), South Carolina (8), South Dakota (1), Texas (24), Utah (46), Virginia (1), Washington (18), Wisconsin (29), and Wyoming (4).

Among people for whom information is available, illnesses started on dates ranging from July 3, 2015 to September 11, 2015. Ill people range in age from less than 1 year to 99, with a median age of 16. Fifty-two percent of ill people are children younger than 18 years. Fifty-four percent of ill people are female. Among 387 people with available information, 112 (29%) report being hospitalized. Three deaths have been reported from Arizona (1), California (1) and Texas (1).

Illnesses that occurred after August 28, 2015 might not be reported yet. A series of events occurs between the time a person is infected and the time public health officials can determine that the person is part of an outbreak. This means that there will be a delay between when a person gets sick and confirmation that he or she is part of an outbreak. This takes an average of 2 to 4 weeks. Please see the Timeline for Reporting Cases of Salmonella Infection for more details.

Investigation Update

CDC’s National Antimicrobial Resistance Monitoring System (NARMS) laboratory conducted antibiotic resistance testing on clinical isolates collected from 6 ill people infected with one of the outbreak strains. Of the 6 isolates tested, all (100%) were susceptible to all antibiotics tested on the NARMS panel. CDC’s NARMS laboratory continues to conduct antibiotic resistance testing on additional clinical isolates collected from ill persons infected with the outbreak strains. Results will be reported when they become available.

Case Count Update

Since the last update on September 9, 2015, 77 new ill people have been reported from Alaska (1), Arizona (6), California (17), Colorado (2), Idaho (6), Indiana (2), Minnesota (8), Montana (3), Nevada (2), New Mexico (4), North Dakota (1), Oklahoma (2), South Carolina (1), Texas (2), Utah (7), Washington (5), Wisconsin (7), and Wyoming (1).

As of September 15, 2015, a total of 418 people infected with the outbreak strains of Salmonella Poona have been reported from 31 states. The number of ill people reported from each state is as follows: Alaska (10), Arizona (72), Arkansas (6), California (89), Colorado (16), Hawaii (1), Idaho (14), Illinois (6), Indiana (2), Kansas (1), Kentucky (1), Louisiana (4), Minnesota (20), Missouri (8), Montana (13), Nebraska (2), Nevada (9), New Mexico (22), New York (4), North Dakota (2), Ohio (2), Oklahoma (10), Oregon (8), Pennsylvania (2), South Carolina (8), Texas (20), Utah (37), Virginia (1), Washington (15), Wisconsin (9), and Wyoming (4).

Among people for whom information is available, illnesses started on dates ranging from July 3, 2015 to September 3, 2015. Ill people range in age from less than 1 year to 99, with a median age of 17. Fifty-two percent of ill people are children younger than 18 years. Fifty-three percent of ill people are female. Among 290 people with available information, 91 (31%) report being hospitalized. Two deaths have been reported from California (1) and Texas (1).

Illnesses that occurred after August 22, 2015 might not be reported yet due to the time it takes between when a person becomes ill and when the illness is reported. This takes an average of 2 to 4 weeks. Please see the Timeline for Reporting Cases of Salmonella Infection for more details.

Investigation Update

On September 11, 2015, Custom Produce Sales voluntarily recalled all cucumbers sold under the Fat Boy label starting August 1, 2015 because they may be contaminated with Salmonella. These cucumbers were sent to Custom Produce Sales from Andrew & Williamson Fresh Produce. Fat Boy label cucumbers were produced in Baja California, Mexico and distributed in the states of California, Colorado, Illinois, Iowa, Nevada, North Dakota, Oklahoma, and Texas. Unlabeled cucumbers packed into a black reusable plastic container, and sold in Nevada as of August 1, 2015, are also covered by this recall. The type of cucumber is often referred to as a “slicer” or “American” cucumber. It is dark green in color and typical length is 7 to 10 inches. In retail locations it is typically sold in a bulk display without any individual packaging or plastic wrapping. These cucumbers are shipped in a black, green, and red cardboard box which reads “Fat Boy Fresh Produce.” Photos of the packing cartons are available.

Several state health and agriculture departments are collecting and testing cucumbers from retail locations for the presence of Salmonella. Since the last update on September 9, 2015, the Arizona Department of Health Services and the Montana Department of Public Health and Human Services isolated one of the outbreak strains of Salmonella Poona from cucumbers collected from retail locations. Preliminary information indicates that these cucumbers were distributed by Andrew & Williamson Fresh Produce. The San Diego County Health and Human Services Agency isolated one of the outbreak strains of Salmonella Poona from cucumbers collected from the Andrew & Williamson Fresh Produce facility.

The National Antimicrobial Resistance Monitoring System (NARMS) is a U.S. public health surveillance system that tracks antibiotic resistance in foodborne and other enteric bacteria found in people, raw meat and poultry, and food-producing animals. NARMS is a partnership among the CDC, the U.S. Food and Drug Administration (FDA), USDA, and state and local health departments.

The NARMS human surveillance program at CDC monitors antibiotic resistance in Salmonella and other bacteria isolated from clinical specimens submitted to NARMS by public health laboratories. CDC’s NARMS laboratory conducted antibiotic resistance testing on clinical isolates collected from 3 ill people infected with one of the outbreak strains. Of the 3 isolates tested, all (100%) were susceptible to all antibiotics tested on the NARMS panel. CDC’s NARMS laboratory continues to conduct antibiotic resistance testing on additional clinical isolates collected from ill persons infected with the outbreak strains. Results will be reported when they become available.

Case Count Update

Since the last update on September 4, 2015, 56 new ill people have been reported from Alaska (1), Arizona (6), California (21), Hawaii (1), Illinois (1), Louisiana (1), Missouri (1), New Mexico (3), Oklahoma (3), Oregon (5), Pennsylvania (2), South Carolina (1), Texas (9), and Washington (1).

As of September 8, 2015, a total of 341 people infected with the outbreak strains of Salmonella Poona have been reported from 30 states. The number of ill people reported from each state is as follows: Alaska (9), Arizona (66), Arkansas (6), California (72), Colorado (14), Hawaii (1), Idaho (8), Illinois (6), Kansas (1), Kentucky (1), Louisiana (4), Minnesota (12), Missouri (8), Montana (10), Nebraska (2), Nevada (7), New Mexico (18), New York (4), North Dakota (1), Ohio (2), Oklahoma (8), Oregon (8), Pennsylvania (2), South Carolina (7), Texas (18), Utah (30), Virginia (1), Washington (10), Wisconsin (2), and Wyoming (3).

Among people for whom information is available, illnesses started on dates ranging from July 3, 2015 to August 30, 2015. Ill people range in age from less than 1 year to 99, with a median age of 15. Fifty-three percent of ill people are children younger than 18 years. Fifty-eight percent of ill people are female. Among 214 people with available information, 70 (33%) report being hospitalized. Two deaths have been reported from California (1) and Texas (1).

Illnesses that occurred after August 16, 2015 might not be reported yet due to the time it takes between when a person becomes ill and when the illness is reported. This takes an average of 2 to 4 weeks. Please see the Timeline for Reporting Cases of Salmonella Infection for more details.

Investigation Update

Several state health and agriculture departments are collecting and testing leftover cucumbers from retail locations for the presence of Salmonella. Since the last update on September 4, 2015, the Nevada Department of Health and Human Services isolated one of the outbreak strains of Salmonella Poona from a cucumber collected from a retail location. Additionally, the Arizona Department of Health Services and the Montana Department of Public Health and Human Services isolated Salmonella from cucumbers collected from retail locations. Preliminary information indicates that these cucumbers were distributed by Andrew & Williamson Fresh Produce. DNA “fingerprinting” is being conducted to determine the pulsed-field gel electrophoresis (PFGE) pattern of the Salmonella isolated from the cucumbers in Arizona and Montana. DNA “fingerprinting” is still ongoing for the Salmonella isolated from cucumbers collected from the Andrew & Williamson Fresh Produce facility by the San Diego County Health and Human Services Agency. Results of additional product testing will be reported when available.

September 4, 2015

CDC, multiple states, and the U.S. Food and Drug Administration (FDA) are investigating a multistate outbreak of Salmonella Poona infections linked to imported cucumbers from Mexico and distributed by Andrew & Williamson Fresh Produce.

Public health investigators are using the PulseNet system to identify illnesses that may be part of this outbreak. PulseNet, the national subtyping network of public health and food regulatory agency laboratories, is coordinated by CDC. DNA “fingerprinting” is performed on Salmonella bacteria isolated from ill people by using a technique called pulsed-field gel electrophoresis, or PFGE. PulseNet manages a national database of these DNA “fingerprints” to identify possible outbreaks. Three DNA “fingerprints” (outbreak strains) are included in this investigation.

As of September 3, 2015, 285 people infected with the outbreak strains of Salmonella Poona have been reported from 27 states. The number of ill people reported from each state is as follows: Alaska (8), Arizona (60), Arkansas (6), California (51), Colorado (14), Idaho (8), Illinois (5), Kansas (1), Louisiana (3), Minnesota (12), Missouri (7), Montana (11), Nebraska (2), Nevada (7), New Mexico (15), New York (4), North Dakota (1), Ohio (2), Oklahoma (5), Oregon (3), South Carolina (6), Texas (9), Utah (30), Virginia (1), Washington (9), Wisconsin (2), and Wyoming (3).

Among people for whom information is available, illnesses started on dates ranging from July 3, 2015 to August 26, 2015. Ill people range in age from less than 1 year to 99, with a median age of 13. Fifty-four percent of ill people are children younger than 18 years. Fifty-seven percent of ill people are female. Among 160 people with available information, 53 (33%) report being hospitalized. One death has been reported from California.

This outbreak can be illustrated with a chart showing the number of people who became ill each day. This chart is called an epidemic curve or epi curve. Illnesses that occurred after August 14, 2015 might not be reported yet due to the time it takes between when a person becomes ill and when the illness is reported. This takes an average of 2 to 4 weeks. Please see the Timeline for Reporting Cases of Salmonella Infection for more details.

Investigation of the Outbreak

Epidemiologic, laboratory, and traceback investigations have identified imported cucumbers from Mexico and distributed by Andrew & Williamson Fresh Produce as a likely source of the infections in this outbreak. The investigation is ongoing.

State and local public health officials are interviewing ill people to obtain information about foods they might have eaten and other exposures in the week before their illness began. In interviews, ill people answered questions about foods eaten and other exposures in the week before their illness began. Fifty-eight (73%) of 80 people interviewed reported eating cucumbers. This proportion was significantly higher than results from a survey [PDF – 29 pages] of healthy people in which 55% reported eating cucumbers in the month of July in the week before they were interviewed.

In addition, numerous ill people were identified as part of illness clusters. An illness cluster is defined as two or more people who do not live in the same household who report eating at the same restaurant location, attending a common event, or shopping at the same location of a grocery store in the week before becoming ill. Investigating illness clusters can provide critical clues about the source of an outbreak. If several unrelated ill persons ate or shopped at the same location of a restaurant or store within several days of each other, it suggests that the contaminated food item was served or sold there. Eleven illness clusters have been identified in seven states. In all of these clusters, interviews found that cucumbers were a food item eaten in common by ill people. Epidemiologic studies that compare foods eaten by both ill and well people are being conducted in two of these clusters. Preliminary results of these studies indicate that a food item containing cucumbers was associated with illness. Preliminary traceback information indicates that cucumbers eaten by ill people in these clusters were imported from Mexico and distributed by Andrew & Williamson Fresh Produce.

Several state health and agriculture departments are collecting leftover cucumbers from restaurants and grocery stores where ill people reported eating or shopping to test for the presence of Salmonella. The San Diego County Health and Human Services Agency isolated Salmonella from cucumbers collected during a visit to the Andrew & Williamson Fresh Produce facility. DNA “fingerprinting” is being conducted to determine the PFGE pattern of the Salmonella isolated from these cucumbers. Results of additional product testing will be reported when available.

Consultation with independent industry experts early in an outbreak investigation also can provide important clues to help focus the investigation on certain suspected foods. An industry consultation was held on August 26, 2015, with four independent experts from the produce industry to obtain information regarding fresh produce harvesting and distribution in the affected region. The consultants provided information regarding crop production and distribution practices that helped assess the plausibility of cucumbers and other produce items as possible outbreak sources.

On September 4, 2015, Andrew & Williamson Fresh Produce voluntarily recalled all cucumbers sold under the “Limited Edition” brand label during the period from August 1, 2015 through September 3, 2015 because they may be contaminated with Salmonella. The type of cucumber is often referred to as a “slicer” or “American” cucumber. It is dark green in color and typical length is 7 to 10 inches. In retail locations it is typically sold in a bulk display without any individual packaging or plastic wrapping. Limited Edition cucumbers were distributed in the states of Alaska, Arizona, Arkansas, California, Colorado, Florida, Idaho, Illinois, Kansas, Kentucky, Louisiana, Minnesota, Mississippi, Montana, Nevada, New Jersey, New Mexico, Oklahoma, Oregon, South Carolina, Texas, and Utah and reached customers through retail, food service companies, wholesalers, and brokers. Further distribution to other states may have occurred.

These cucumbers are shipped in a black, green, yellow, and craft colored carton which reads “Limited Edition Pole Grown Cucumbers.” Labeling on the cases of recalled cucumbers indicates the product was grown and packed by Rancho Don Juanito in Mexico. Domestically produced cucumbers are not believed to be involved in this outbreak.

CDC’s National Antimicrobial Resistance Monitoring System (NARMS) laboratory is conducting antibiotic resistance testing on clinical isolates collected from ill people infected with the outbreak strains; results will be reported when they become available.

This investigation is rapidly evolving. CDC and state and local public health partners are continuing laboratory surveillance through PulseNet to identify additional ill people and to interview them. Updates will be provided when more information is available.