Poopy salad still weighs on public health

As the food stress pandemic hits the holiday season last week, many of us will be considering healthy salads in the coming days. But if there’s one constant we can count on in this year of upheaval, it’s the enduring possibility that our leafy greens are tainted with poo bacteria.

The Centers for Disease Control and Prevention currently has three open investigations into Escherichia coli outbreaks – two directly related to leafy greens and one involving a bacterial strain that caused an outbreak in 2018 related to romaine lettuce.

Meanwhile, the Food and Drug Administration had issued four separate safety alerts for the salad fixings recalled this month. Three of the recalls involved romaine lettuce – a now notorious source of gut-destroying bacteria – for potential E. coli contamination. Over the past weekend, the FDA added baby spinach to the list, another common culprit, for the potential Salmonella contamination.

Only one of the recalls has so far been directly linked to an outbreak. On November 6, Tanimura & Antle Inc. voluntarily recalled its packaged one-head romaine lettuce (labeled as packaged on October 15, 2020 or October 16, 2020) from beyond possible E. coli contamination. Routine laboratory tests in Michigan have identified a strain of E. coli in the soiled salad sample which turned out to be disgusting people. In all, 12 people in six states have been infected with this particular strain, and five of those infected have been hospitalized. Of 11 people surveyed, all said they ate various types of leafy greens, including romaine lettuce (5), spinach (5), iceberg lettuce (3) and red leaf lettuce (3), notes the CDC.

Poopy possibilities

The agency noted a similar trend in another E. coli investigation into the outbreak, which was last updated on November 23. In that outbreak, 39 people were sick in 18 states, with 19 people ending up in hospital. Of the 22 sick people the health investigators were able to interview, all said they ate a variety of leafy greens, such as spinach (16), romaine lettuce (15), iceberg lettuce (12) and lettuce in mixed bag (8). “No type or brand of leafy greens or other food has been identified as the source of this epidemic,” the CDC added.

In the third E. coli outbreak investigation, the researchers did not specifically touch the leafy greens. The outbreak, which began in June, has left 21 people sick in eight states, with eight people needing hospitalization. One person died. The CDC notes that the E. coli strain in this outbreak was also the source of a massive outbreak in several states in 2018 linked to romaine lettuce. This outbreak sickened 210 people in 36 states, sending 96 people to hospital. Five people died. The CDC warned that “food linked to a previous outbreak alone is not enough to prove a link in another outbreak of the same strain. This is because different foods can be contaminated with the same strain of bacteria. The agency noted that “several” people sick from the current outbreak all appeared to be infected in the same restaurant. Yet health investigators did not identify a specific food as the source of the outbreak.

In all outbreak investigations, researchers have identified strains of E. Coli O157: H7, otherwise harmless. E. coli strains carrying pathogenic toxins originating from Shigella dysenteriae bacteria (aka Shiga toxins). In infected people, Shiga toxins cause stomach cramps, vomiting, and diarrhea (often bloody). Some people develop a low fever. In severe cases, the toxins can cause a type of kidney failure called hemolytic uremic syndrome (HUS), which can lead to permanent organ damage and even death.

The main source of these E. coli Strains O157: H7 are the intestines of cattle, especially cattle. They are often thought to reach the leaves of lettuce by runoff from livestock farms and contaminated water sources used for crop irrigation. The massive outbreak of 2018, for example, was linked to manure from a high-density cattle farm found contaminating the canal water upstream from contaminated lettuce fields.