As the world grapples with the issue of food safety, one persistent problem has been the contamination of romaine lettuce by E. coli bacteria. A new study from Cornell University sheds light on the root causes of this issue and proposes practical solutions to minimize risks to human health.

The research, co-authored by Renata Ivanek and Martin Wiedmann, two renowned experts in food safety, identifies key interventions that can make a significant difference in ensuring the safety of romaine lettuce. These include:

1. Reducing produce contamination: By addressing contaminated irrigation water as a major source of bacterial contamination, farmers and producers can minimize the risk of E. coli outbreaks.
2. Improving temperature control: Proper cold storage temperatures along the entire supply chain are crucial to preventing bacterial growth and maintaining food quality.
3. Optimizing postharvest techniques: Consistent application of produce washes during processing can significantly reduce bacterial numbers, while switching from overhead spray irrigation systems to drip or furrow irrigation can also minimize risk.

According to Ivanek, the study’s findings suggest that contaminated irrigation water is a significant contributor to E. coli contamination in romaine lettuce. By using untreated surface water for irrigation through overhead spray systems, farmers inadvertently introduce bacteria into the produce. Switching to treated water or using drip or furrow irrigation can significantly reduce this risk.

In addition to these interventions, Ivanek emphasizes the importance of proper temperature control during transportation and storage. A “perfect storm” of contamination occurs when bacteria are introduced at the farm or processing level, only to be allowed to grow due to improper temperatures during transport.

The comprehensive practices explored in this study aim to aid decision-makers in establishing and enhancing food safety best management practices. Ivanek notes that the American food supply chain is relatively safe compared to other countries, but there is still room for improvement.

By implementing these practical solutions, farmers, producers, and policymakers can work together to make the romaine lettuce supply chain even safer for consumers.

MIT scientists have made a groundbreaking discovery in boosting the efficiency of an essential enzyme that powers all plant life – rubisco. By using a directed evolution technique, they were able to enhance a version of rubisco found in bacteria from low-oxygen environments by up to 25 percent. This breakthrough has significant implications for improving crop yields and reducing energy waste in plants.

The researchers used a newer mutagenesis technique called MutaT7, which allowed them to perform both mutagenesis and screening in living cells, dramatically speeding up the process. They began with a version of rubisco isolated from semi-anaerobic bacteria known as Gallionellaceae, one of the fastest rubiscos found in nature.

After six rounds of directed evolution, the researchers identified three different mutations that improved the rubisco’s resistance to oxygen and increased its carboxylation efficiency. These mutations are located near the enzyme’s active site, where it performs carboxylation or oxygenation.

The MIT team is now applying this approach to other forms of rubisco, including those found in plants. Plants lose about 30 percent of the energy from sunlight they absorb through a process called photorespiration, which occurs when rubisco acts on oxygen instead of carbon dioxide.

“This really opens the door to a lot of exciting new research, and it’s a step beyond the types of engineering that have dominated rubisco engineering in the past,” said Robert Wilson, a research scientist in the Department of Chemistry. “There are definite benefits to agricultural productivity that could be leveraged through a better rubisco.”

The research was funded by several organizations, including the National Science Foundation and the Abdul Latif Jameel Water and Food Systems Lab Grand Challenge grant.

This breakthrough has significant implications for improving crop yields and reducing energy waste in plants. The researchers’ directed evolution technique allows them to look at a lot more mutations in the enzyme than has been done in the past, making it a compelling demonstration of successful improvement of a rubisco’s enzymatic properties.

Scientists in China have made a groundbreaking discovery that could potentially alter our understanding of pandemics. Researchers from the Yunnan Institute of Endemic Disease Control and Prevention have found two new viruses in bats that are closely related to the deadly Nipah and Hendra viruses, which can cause severe brain inflammation and respiratory disease in humans.

The study, published in the open-access journal PLOS Pathogens, analyzed 142 bat kidneys from ten species collected over four years across five areas of Yunnan province. Using advanced genetic sequencing, the team identified 22 viruses – 20 of them never seen before. Two of these newly discovered viruses belong to the henipavirus genus, which includes Nipah and Hendra viruses known for their high fatality rates in humans.

The researchers’ findings are concerning because these henipaviruses can spread through urine, raising the risk of contaminated fruit and the possibility of the viruses jumping to humans or livestock. This highlights the importance of comprehensive microbial analyses of previously understudied organs like bat kidneys to better assess spillover risks from bat populations.

As bats are natural reservoirs for a wide range of microorganisms, including many notable pathogens that have been transmitted to humans, it is essential to conduct thorough research on these animals’ infectomes. This study not only broadens our understanding of the bat kidney infectome but also underscores critical zoonotic threats and highlights the need for comprehensive microbial analyses.

The authors emphasize that their findings raise urgent concerns about the potential for these viruses to spill over into humans or livestock, making it crucial for scientists, policymakers, and public health officials to work together to mitigate this risk. By analyzing the infectome of bat kidneys collected near village orchards and caves in Yunnan, the researchers have uncovered not only the diverse microbes bats carry but also the first full-length genomes of novel bat-borne henipaviruses closely related to Hendra and Nipah viruses identified in China.

Funding for this study came from various grants and programs, including the National Key R&D Program of China, Yunnan Revitalization Talent Support Program Top Physician Project, National Natural Science Foundation of China, and others. The funders had no role in study design, data collection, analysis, decision to publish, or preparation of the manuscript.