Multistate Outbreak of Listeriosis Linked to Blue Bell Creameries Products (Final Update)

Introduction

This was a complex multistate outbreak investigation of listeriosis cases occurring over several years. Public health investigators used the PulseNet system to identify illnesses that were part of this outbreak. PulseNet is the national subtyping network of public health and food regulatory agency laboratories coordinated by CDC. DNA “fingerprinting” is performed on Listeria bacteria isolated from ill people using techniques called pulsed-field gel electrophoresis (PFGE) and whole genome sequencing (WGS). WGS gives a more detailed DNA fingerprint than PFGE. PulseNet manages a national database of these DNA fingerprints to identify possible outbreaks of enteric illness. Several PFGE patterns (strains) of Listeria were involved in this outbreak.

A total of 10 people infected with several strains of Listeria were reported from 4 states: Arizona (1), Kansas (5), Oklahoma (1), and Texas (3). Illness onset dates ranged from January 2010 through January 2015. The people with illness onsets during 2010–2014 were identified through a retrospective review of the PulseNet database for DNA fingerprints matching isolates collected from Blue Bell ice cream samples. All 10 (100%) people were hospitalized. Three deaths were reported from Kansas.

Investigation of the Outbreak

February 2015

In February 2015, the South Carolina Department of Health and Environmental Control isolated Listeria as part of routine sampling from Blue Bell brand single-serving ice cream products collected from a distribution center: Chocolate Chip Country Cookie Sandwiches and Great Divide Bars. In response to the findings in South Carolina, the Texas Department of State Health Services collected product samples from the Blue Bell Creameries production facility in Brenham, Texas, that made these products. Testing by Texas health officials yielded Listeria isolates from some samples of the same two products tested by South Carolina and from another Blue Bell ice cream product called “Scoops.” This product was made on the same production line as the Chocolate Chip Country Cookie Sandwiches and Great Divide Bars. PFGE was performed on the Listeria isolated from the ice cream samples; seven different PFGE patterns were identified and uploaded to PulseNet.

March 2015

In March 2015, Kansas health officials identified two people from the same hospital who were infected with Listeria bacteria that had the same PFGE pattern. Three additional listeriosis cases with three other PFGE patterns had previously been identified from the same hospital. All five people were hospitalized for unrelated problems before developing invasive listeriosis — a finding that strongly suggested their infections were acquired in the hospital. Listeria isolates from four of the five people had PFGE patterns that were also identified in ice cream tested by South Carolina and Texas. Although some of the illnesses occurred more than a year before this investigation began, all four people with available information consumed milkshakes made with the “Scoops” Blue Bell ice cream product while they were in the hospital. Isolates from four of these people were highly related to each other by whole genome sequencing. Listeria isolated from the fifth person was not related to isolates from the other four ill people. In addition, the PFGE pattern was not identified in any ice cream samples. However, this person was part of a recognized illness cluster at the hospital and consumed milkshakes made with “Scoops” while hospitalized. As a result, this person was included as a case in the outbreak.  Illness onset dates for the five people ranged from January 2014 through January 2015. Three of these people died as a result of their Listeria infection.

On March 13, 2015, Blue Bell Creameries reported removing the “Scoops” ice cream product and other products made on the same production line from the market. The company also reported that it had shut down that production line at its Brenham, Texas, facility.

On March 22, 2015, the Kansas Department of Health and Environment (KDHE) reported that Listeria was isolated from a previously unopened, single-serving Blue Bell brand 3 oz. institutional/food service chocolate ice cream cup collected from the Kansas hospital involved in the outbreak. Samples of Blue Bell brand 3 oz. institutional/food service chocolate ice cream cups collected from the company’s Broken Arrow, Oklahoma, facility also yielded Listeria. Listeria isolated from ice cream cup samples were indistinguishable from each other by PFGE, but were different from those isolated from people in Kansas and from other Blue Bell brand ice cream products previously sampled in Texas and South Carolina. On March 23, 2015, Blue Bell announced a recall of 3 oz. institutional/food service ice cream cups (with tab lids) of several flavors produced at the company’s Broken Arrow, Oklahoma, facility.

April 2015

On April 3, 2015, CDC reported that illnesses might be linked to ice cream made in Blue Bell Creameries’ Oklahoma facility, but lacked sufficient information to include them as cases in the outbreak at the time. These illnesses were identified when investigators searched the PulseNet database and identified 6 people from Arizona (1), Oklahoma (1), and Texas (4) with listeriosis between 2010 and 2014 who had Listeria isolates with PFGE patterns indistinguishable from isolates from the chocolate ice cream cups made in the Broken Arrow, Oklahoma, facility. The four people reported from Texas were hospitalized for unrelated problems before developing listeriosis. Information available for one person indicated that they consumed ice cream in a Texas hospital before developing listeriosis; the Texas Department of State Health Services reported that the hospital had received Blue Bell brand ice cream cups. None of the four people in Texas died from Listeria infection. At this point in the investigation, CDC recommended that consumers not eat and institutions and retailers not serve any products made at the company’s Oklahoma facility, in addition to any previously recalled or withdrawn products. That day, Blue Bell Creameries reported that they had voluntarily suspended operations at their facility in Oklahoma.

On April 8, 2015, CDC reported that whole genome sequencing confirmed that three of the four isolates from people in Texas were nearly identical to Listeria strains isolated from ice cream produced at Blue Bell Creameries’ Oklahoma facility. These three people were added to the case count for the outbreak, bringing the total to 8. The fourth isolate was later determined not to be part of the outbreak by whole genome sequencing and this illness was not added to the case count.

On April 20, 2015, Blue Bell Creameries voluntarily recalled all products currently on the market made at all of its facilities, including ice cream, frozen yogurt, sherbet, and frozen snacks.Blue Bell announced this recall after sampling by the company revealed that Chocolate Chip Cookie Dough Ice Cream half gallons produced on March 17, 2015, and March 27, 2015, contained Listeria.

On April 21, CDC reported that whole genome sequencing confirmed that the people from Arizona (1) and Oklahoma (1) were part of the outbreak, bringing the total case count to 10.

May 2015

On May 7, 2015, FDA released the findings from recent inspections at the Blue Bell production facilities in Brenham, Texas [PDF – 4 pages]; Broken Arrow, Oklahoma [PDF – 11 pages]; and Sylacauga, Alabama [PDF – 5 pages].

This outbreak investigation is over. However, people could continue to get sick because recalled products may still be in people’s freezers and consumers unaware of the recalls could eat them. Institutions should not serve and retailers should not sell recalled products. These products are frozen, so consumers, institutions, and retailers should check their freezers. Read the Advice to Consumers, Institutions, and Retailers.

Final Case Count Update

A total of 10 people infected with several strains of Listeria monocytogenes were reported from 4 states: Arizona (1), Kansas (5), Oklahoma (1), and Texas (3). There were no changes to the case count since the last update on April 21. Illness onset dates ranged from January 2010 through January 2015. The people with illness onsets during 2010-2014 were identified through a retrospective review of the PulseNet database for DNA fingerprints matching isolates collected from Blue Bell ice cream samples. All 10 (100%) people were hospitalized. Three deaths were reported from Kansas.

Case Count Update

As of April 21, 2015, a total of ten patients infected with several strains of Listeria monocytogenes were reported from four states: Arizona (1), Kansas (5), Oklahoma (1), and Texas (3). Illness onset dates ranged from January 2010 through January 2015. The patients with illness onsets ranging from 2010-2014 were identified through a retrospective review of the PulseNet database for DNA fingerprints that were similar to isolates collected from Blue Bell ice cream samples. Since the last update on April 8, 2015, two additional patients, one each from Arizona and Oklahoma, were confirmed to be a part of the outbreak by whole genome sequencing. All ten (100%) patients were hospitalized. Three deaths were reported from Kansas.

One additional isolate from a patient with listeriosis is undergoing further molecular laboratory testing to determine whether this illness may be related to this outbreak. Results of this testing will be reported once they are available. CDC and state and local public health partners are continuing laboratory surveillance through PulseNet to identify any other ill persons that may be part of this outbreak.

Investigation Update

On April 20, 2015, Blue Bell Creameries voluntarily recalled all of its products currently on the market made at all of its facilities, including ice cream, frozen yogurt, sherbet, and frozen snacks, because they have the potential to be contaminated with Listeria monocytogenes. Blue Bell announced this recall after sampling by the company revealed that Chocolate Chip Cookie Dough Ice Cream half gallons produced on March 17, 2015 and March 27, 2015 contained the bacteria. Listeria monocytogenes was previously found in other Blue Bell products. CDC recommends that consumers do not eat any Blue Bell brand products, and that institutions and retailers do not serve or sell them.

State and local health officials, CDC, and FDA continue to work closely on this investigation, and new information will be provided on this website as it becomes available.

Case Count Update

This is a complex and ongoing multistate investigation of listeriosis occurring over an extended period. Several strains of Listeria monocytogenes are involved in this outbreak. Information indicates that various Blue Bell brand products produced in facilities in Texas and Oklahoma are the source of this outbreak.

The outbreak consists of two clusters of people infected with several strains of Listeria monocytogenes that were also found in products made at two Blue Bell facilities in Texas and Oklahoma. Eight people with Listeria infections related to this outbreak have been confirmed from two states: Kansas (5) and Texas (3). Three deaths were reported from Kansas.

Cluster 1 consists of five patients reported from Kansas during January 2014 through January 2015 who were all hospitalized at a single hospital for unrelated problems before developing listeriosis. Of the four ill people for whom information is available on the foods eaten in the month before Listeria infection, all consumed milkshakes made at the hospital with a Blue Bell brand ice cream product called “Scoops.” Whole genome sequences of Listeria monocytogenes strains isolated from four of the patients were found to be highly related to sequences of Listeria strains isolated from “Scoops” and two other products made on the same line at the company’s Texas facility. These products were recalled by Blue Bell Creameries on March 13, 2015.

Cluster 2 consists of three patients reported from Texas during 2011 through 2014 who were all hospitalized for unrelated problems before developing listeriosis. Whole genome sequences of their Listeria monocytogenes strains were nearly identical to Listeria strains isolated from ice cream produced at the Blue Bell Creameries’ Oklahoma facility.

Three additional patients with listeriosis during 2010 through 2012 whose isolates have PFGE patterns similar to those of others in the cluster have been identified in the PulseNet database; further molecular laboratory testing is under way to determine whether these illnesses may be related to this outbreak. Results of this testing will be reported once they are available.

Investigation Update

The Food and Drug Administration (FDA) recently isolated Listeria monocytogenes strains from a 1-pint container of Blue Bell brand banana pudding ice cream collected from the company’s Oklahoma production facility. This contaminated product was produced in the same facility but on a different line from the 3 oz. institutional/food service ice cream cups previously recalled.

On April 3, 2015, Blue Bell Creameries reported that they had voluntarily suspended operations at their Oklahoma production facility.  On April 7, 2015, Blue Bell Creameries announced a third product recall that included banana pudding ice cream pints and other products made on the same line that were produced between February 12, 2015 and March 27, 2015 at their Oklahoma facility. Further testing of environmental and product samples from Blue Bell Creamery facilities is ongoing.

Blue Bell Creameries previously issued two other recalls. On March 13, 2015, the company removed from the market “Scoops” and other products made on the same line at their Texas facility. On March 23, 2015, the company recalled 3 oz. institutional/food service ice cream cups of chocolate, strawberry, and vanilla flavors made at their Oklahoma facility.

CDC continues to recommend that consumers do not eat any Blue Bell brand products made at the Oklahoma production facility (including the recalled products) and that retailers and institutions should not sell or serve them. This advice is particularly important for consumers at higher risk for listeriosis, including pregnant women, adults 65 and older, and people with weakened immune systems. Learn more on the Advice page.

In addition, CDC continues to recommend that consumers do not eat any products that Blue Bell Creameries recalled.

State and local health officials, CDC, and FDA continue to work closely on this investigation, and new information will be provided on this website as it becomes available.

Investigation Update

On March 22, 2015, the Kansas Department of Health and Environment (KDHE) reported that Listeria monocytogenes was isolated from a previously unopened, single-serving Blue Bell brand 3 oz. institutional/food service chocolate ice cream cup collected from the Kansas hospital involved in the outbreak. Samples of Blue Bell brand 3 oz. institutional/food service chocolate ice cream cups collected from the company’s Oklahoma facility have also yielded Listeria monocytogenes strains. Listeria isolates from ice cream cup samples were indistinguishable from each other by pulsed-field gel electrophoresis (PFGE), but were different from those isolated from patients in Kansas and from other Blue Bell brand ice cream products previously sampled in Texas and South Carolina. The pattern is rare.

CDC searched the PulseNet database and identified six patients with listeriosis between 2010 and 2014 who had Listeria isolates with PFGE patterns indistinguishable from those of Listeria isolated from Blue Bell brand 3 oz. institutional/food service chocolate ice cream cups. Four of these six patients had been hospitalized in Texas for unrelated problems before developing listeriosis. Information is available for one patient; that patient reported consuming ice cream in a Texas hospital before developing listeriosis, and the Texas Department of State Health Services reported that the hospital had received Blue Bell brand ice cream cups. Investigation to determine whether these illnesses are related to exposure to Blue Bell products is ongoing.

Based on the information CDC has at this time, we recommend that consumers do not eat any Blue Bell brand products made at the company’s Oklahoma facility and that retailers and institutions do not sell or serve them. This advice is particularly important for consumers at higher risk for listeriosis, including pregnant women, adults 65 and older, and people with weakened immune systems. The contaminated products may be in the freezers of consumers, retailers, and institutions.  On April 3, 2015, Blue Bell Creameries reported that they had voluntarily suspended operations at their facility in Oklahoma. Blue Bell brand products made at the Oklahoma facility can be identified by checking for letters “O,” “P,” “Q,” “R,” “S,” and “T” following the “code date” printed on the bottom of the product package. Learn more on the Advice page .

In addition, CDC recommends that consumers do not eat any products that Blue Bell Creameries recalled or removed from the market .

State and local health officials, CDC, and FDA continue to work closely on this investigation, and new information will be provided on this website as it becomes available.

Investigation Update

The information available at this time indicates that certain Blue Bell brand ice cream products are the source of this outbreak. Listeria can cause a serious, life-threatening illness.

The Kansas Department of Agriculture’s (KDA) laboratory isolated Listeria monocytogenes from a previously unopened, single-serving Blue Bell brand 3 oz. institutional/food service chocolate ice cream cup obtained in March 2015 from the hospital associated with this outbreak. This cup was produced in the Broken Arrow, Oklahoma, plant on April 15, 2014. Molecular subtyping information is not yet available for this isolate. KDA also tested environmental samples from the hospital kitchen, but none yielded Listeria monocytogenes.

On March 23, 2015, Blue Bell Ice Cream of Brenham, Texas, announced a recall of 3 oz. institutional/food service ice cream cups (with tab lids) of the following flavors: chocolate, strawberry, and vanilla. These ice cream cups were distributed in Alabama, Arizona, Arkansas, Colorado, Florida, Georgia, Illinois, Indiana, Kansas, Kentucky, Louisiana, Mississippi, Missouri, Nevada, New Mexico, North Carolina, Ohio, Oklahoma, South Carolina, Tennessee, Texas, Virginia, and Wyoming via food service accounts. These cups are sold to institutions, which may include schools, nursing homes, and hospitals; according to Blue Bell Creameries, they are not sold through retail outlets, such as convenience stores or supermarkets. CDC recommends that consumers do not eat recalled products and that institutions and retailers do not sell or serve them. Investigation into whether other products were produced on the same line as the 3 oz. institutional/food service ice cream cups is ongoing, and new information will be provided as it becomes available.

The South Carolina Department of Health and Environmental Control isolated Listeria monocytogenes from the following Blue Bell brand single-serving ice cream products collected from a distribution center in 2015: Chocolate Chip Country Cookie Sandwiches and Great Divide Bars.  In response to the findings in South Carolina, the Texas Department of State Health Services collected product samples from the Blue Bell Creameries production facility in Brenham, Texas. These samples yielded Listeria monocytogenes from the same two products tested by South Carolina and also from the ice cream Scoops, which is made on the same production line.

Three strains of Listeria monocytogenes isolated from the ice cream samples had PFGE patterns that were indistinguishable from those of Listeria bacteria obtained from samples from four patients, and whole genome sequencing subsequently also showed that the strains were highly related to those isolated from four patients. Listeria monocytogenes isolates with four other PFGE patterns were also isolated from the ice cream samples.

Invoices provided by the hospital to the Kansas Department of Health and Environment indicate that the Blue Bell brand ice cream Scoops used in the patients’ milkshakes came from Blue Bell Creamery’s facility in Texas. Further whole genome sequencing of Listeria monocytogenes isolates obtained from the ice cream is in progress.

Blue Bell Creameries has reported removing from the market the Scoops ice cream product and other products made on the same production line, which the company has reportedly shut down. These ice cream products were distributed in Alabama, Arizona, Arkansas, Colorado, Florida, Georgia, Illinois, Indiana, Kansas, Kentucky, Louisiana, Mississippi, Missouri, Nevada, New Mexico, North Carolina, Ohio, Oklahoma, South Carolina, Tennessee, Texas, Virginia, and Wyoming via select stores and food service accounts.

Contaminated ice cream products may still be in the freezers of consumers, institutions, and retailers, given that these products can have a shelf life of up to 2 years. CDC recommends that consumers do not eat products that Blue Bell Creameries recalled or removed from the market, and institutions and retailers should not serve or sell them. A detailed list of products is available on the Advice page . State and local health officials, CDC, and FDA continue to work closely on this investigation, and new information will be provided on this website as it becomes available.

March 13, 2015

Introduction

State and local health officials, CDC, and FDA are collaborating to investigate an outbreak of Listeria monocytogenes infections (listeriosis). The joint investigation found that certain Blue Bell brand ice cream products are the likely source for some or all of these illnesses. Listeria can cause a serious, life-threatening illness.

Public health investigators are using the PulseNet system to identify illnesses that may be part of this outbreak. PulseNet is the national subtyping network of public health and food regulatory agency laboratories coordinated by CDC. DNA “fingerprinting” is performed on Listeria bacteria isolated from ill people using techniques called pulsed-field gel electrophoresis (PFGE) and whole genome sequencing (WGS). WGS gives a more detailed DNA fingerprint than PFGE. PulseNet manages a national database of these DNA fingerprints to identify possible outbreaks.

The five ill people included in this outbreak investigation have been reported from Kansas and were each infected with one of four strains of Listeria monocytogenes identified by PFGE.  All five people were hospitalized at the same hospital for unrelated problems before developing invasive listeriosis — a finding that strongly suggests their infections were acquired in the hospital. Isolates from four of these patients are highly related by whole genome sequencing. Illness onset dates for the five patients ranged from January 2014 through January 2015. Although some illnesses occurred more than a year ago, the cluster was identified in March 2015 after health officials noted that two patients who had been in the same hospital were infected with Listeria monocytogenes bacteria that were indistinguishable by PFGE. All five ill people are older adults, and three are women. Three deaths have been reported.

Investigation of the Outbreak

The information available at this time indicates that certain Blue Bell brand ice cream products are the likely source of this outbreak. Listeria can cause a serious, life-threatening illness. Of the four ill people for whom information is available on the foods eaten in the month before Listeria infection, all four consumed milkshakes made with a single-serving Blue Bell brand ice cream product called “Scoops” while they were in the hospital.

In an unrelated investigation, the South Carolina Department of Health and Environmental Control isolated Listeria monocytogenes from the following Blue Bell brand single-serving ice cream products collected from a distribution center in 2015: Chocolate Chip Country Cookie Sandwiches and Great Divide Bars.  In response to the findings in South Carolina, the Texas Department of State Health Services collected product samples from the Blue Bell Creameries production facility in Brenham, Texas. These samples yielded Listeria monocytogenes from the same two products tested by South Carolina and also from the ice cream Scoops, which is made on the same production line. Listeria monocytogenes was not found in other Blue Bell brand ice cream products tested.

Three strains of Listeria monocytogenes isolated from the ice cream samples had PFGE patterns that were indistinguishable from those of Listeria bacteria obtained from samples from four patients. Listeria monocytogenes isolates with four other PFGE patterns were also isolated from the ice cream samples. Invoices provided by the hospital to the Kansas Department of Health and Environment indicate that the Blue Bell brand ice cream Scoops used in the patients’ milkshakes came from Blue Bell Creamery’s facility in Texas. Whole genome sequencing of the Listeria monocytogenes isolates obtained from the ice cream is in progress.

One patient’s Listeria monocytogenes strain has a PFGE pattern that does not match any identified in an ice cream sample. However, epidemiologic evidence, including acquiring infection at the same hospital as the other patients and consumption of the ice cream products, suggests that this illness may be related. CDC and state and local public health partners are continuing laboratory surveillance through PulseNet to identify any additional ill persons whose illnesses may be related to this outbreak.

Blue Bell Creameries has reported removing from the market the Scoops ice cream product and other products made on the same production line. The company also has reported that it has shut down that production line.

Contaminated ice cream products may still be in the freezers of consumers, institutions, and retailers, given that these products can have a shelf life of up to 2 years. CDC recommends that consumers do not eat products that Blue Bell Creameries removed from the market, and institutions and retailers should not serve or sell them. A detailed list of products is available on the Advice page . State and local health officials, CDC, and FDA continue to work closely on this investigation, and new information will be provided on this website as it becomes available.

 Top of Page