On September 30, 2016, the CDC published their final update to the outbreak of Salmonella Reading and Salmonella Abony that had been linked to various alfalfa sprout products. The final case count of the outbreak rests at 36. Out of those sickened in the outbreak, 7 required hospitalization because of their illness. There were no deaths reported. There were 9 states impacted by this outbreak, including Colorado with 17 cases, Kansas with 9 cases, Minnesota with 1 case Missouri with 1 case, Nebraska with 3 cases, New York with 1 case, Oregon with 1 case, Texas with 1 case, and Wyoming with 2 cases. There were two different strains of Salmonella associated with the outbreak, Salmonella Abony and Salmonella Reading. Thirty people involved in the outbreak were infected with Salmonella Reading. One person was infected with Salmonella Abony. Five people were infected with both of the outbreak strains. The illnesses linked to this outbreak had onset dates between May 21 and September 10, 2016.
Upon hearing of the outbreak, the CDC, along with state and local health officials, began to look for a source of the outbreak. Both epidemiologic and traceback evidence led the CDC to conclude that the source of the outbreak was Sprouts Extraordinaire, a Denver, Colorado based company. Over the course of the investigation the CDC conducted interviews with 31 of the people sickened in the outbreak. Eighteen of the interviewees reported potentially eating alfalfa sprouts in the week prior to their becoming infected with Salmonella. Several of those interviewed also reported eating sprouts at a restaurant. Health officials were then able to look at 5 different restaurants. All of the restaurants visited by ill people were supplied alfalfa sprouts by Sprouts Extraordinaire.
After it was discovered that Sprouts Extraordinaire was the source of the outbreak, they issued a recall for several of their products. On August 5, 2016, the CDC issued a recall for all alfalfa sprouts products made by Sprouts Extraordinaire. It was reported that the products were sold in 5 pound boxes, and have the label “Living Alfalfa Sprouts” on the box. The CDC did not release any other identifying information, and where the products were distributed to is also unknown. At the time of the recall, the CDC recommended that any retailers or restaurants with the recalled sprouts in stock should dispose of them.
Sprouts are a very common source of foodborne illness outbreaks, having caused upwards of 30 outbreaks since 1996. The latest major outbreak linked to alfalfa sprouts took place earlier this year. A different strain of Salmonella, Salmonella Muenchen, caused an early 2016 outbreak. The CDC investigation for that outbreak ended on May 13, 2016. By the end of the investigation, 26 people had been sickened in the outbreak, across 12 states. The illness hospitalized eight people because of the severity. The investigation was able to uncover that Sweetwater Farms, of Inman, Kansas, was the source of the outbreak. Sweetwater Farms recalled all of its sprout products after they heard of the outbreak.
Sprouts carry a higher risk of being contaminated. Sprouts, unlike some other vegetables, require a warm and humid environment in order to grow well. Bacteria, including Salmonella, also grow the best under warm and humid conditions. On top of this, alfalfa sprouts are often served raw or lightly cooked, making it much easier for the bacteria to remain on the sprouts. Bacteria have also been known to thrive inside the seed of the alfalfa sprout, making it even harder to remove all traces of bacteria from the vegetables. In fact, despite the fact that there are several methods for removing bacteria from sprouts, there is no 100% effective way to prevent contamination.
Salmonella infections are one of the most common forms of foodborne illness. Health Officials first tracked Salmonella in 1962, but they first detected Salmonella long before that. Dr. Salmon first discovered the bacteria and its effects more than 125 years ago. The CDC estimates that Salmonella bacteria infects about 1.2 million people each year in the United States. This leads to the hospitalization of about 19,000 people each year. There are an estimated 450 deaths caused by Salmonella infections. There are many different strains of Salmonella bacteria, but all will cause illness in humans. The 32 different serotypes, or strains, of Salmonella bacteria help investigators pinpoint potential outbreaks, as well as their sources.
When the number of infections reported increases rapidly and suddenly, it is an indicator to health officials that an outbreak is taking place. Health officials can then investigate the outbreak, usually by taking samples and by conducting interviews. There is sometimes a correlation between interview answers, which can help investigators locate a source. In this outbreak, investigators discovered that 17 of those sickened in the outbreak ate sprouts before their illness began. Although interviews can help locate potential sources, the best way for health officials to learn more about an outbreak is through the testing of samples. When medical providers retrieve samples from ill people or from the environment, the samples undergo testing to learn more about them. This type of testing reveals is the bacteria’s DNA fingerprint. This fingerprint, a solution of the process of pulsed field gel electrophoresis, is unique to the bacteria and strain involved in the outbreak. The DNA fingerprint is then uploaded to the PulseNet system. The PulseNet system is a database of DNA fingerprints maintained by the CDC. If a saved sample matches another sample, there may be a connection between the two. When multiple samples match through the PulseNet system, it is another clue to investigators about the origin and size of the outbreak.
A case of Salmonella poisoning will generally produce symptoms within 12 and 72 hours after infection. Usually, Salmonella infections will produce symptoms including vomiting, fever, abdominal cramping, and nausea. While a Salmonella infection may subside on its own within a week, the infection may worsen or cause severe dehydration. This may make hospitalization necessary. Those with certain risk factors, including the elderly, children, and those with suppressed immune systems may be at an increased risk of developing a serious Salmonella infection. If you or a loved one begin to show the symptoms of Salmonella poisoning, contact a medical professional.