Tag Archives: Food Science

Microbiology

The Future of Food Safety: Detecting Pathogens Before They Cause Illness

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Common food items like lettuce and spinach are regularly subjected to testing for harmful bacteria such as salmonella, listeria monocytogenes, and dangerous strains of E. coli as a means of preventing consumer illness.

Despite the availability of quick testing methods, it’s still a time-consuming process to determine who fell ill and trace the source of the tainted produce. That’s far too late for the many Americans who already ate the produce. The current solution, frequently involving a recall spanning multiple states, essentially amounts to damage control.

The University of Delaware researchers want to spot these bacteria before anyone ever falls ill. As detailed in an article published in the Journal of Food Safety, UD and Delaware-based startup Biospection are about to speed up testing — a lot. Faculty members Harsh Bais and Kali Kniel, alongside former graduate student Nick Johnson, teamed up with Andy Ragone of Biospection to detect foodborne pathogens in three to six hours.

A microbiologist by trade, Kniel is an expert on crossover pathogens like salmonella, which gleefully jump to new hosts like that delicious, fresh lettuce.

“While the produce industry is working diligently to reduce risks associated with microbial contamination, tools like this have incredible potential to improve risk reduction strategies,” said Kniel, professor of microbial food safety who works regularly with industry and government agencies to reduce risk of foodborne illness. “Collaborations like ours between academics and biotechnology companies can enhance technology and impact food safety and public health.”

These pathogens easily find their way into plants, which are unfortunately very welcoming hosts — hosts that can’t tell you where their guests are.

Just like humans, plants use defense mechanisms to fight disease. But some human-borne pathogens learned to push open a plant’s open-entry gates called stomates — pores in the leaves or stem — and make themselves at home.

“Because these bacteria are not true pathogens for plants, you cannot physically see early signs that the plant is under stress,” said Bais, UD professor of plant biology. “Biospection’s technology allows us to say, very quickly, if the opportunistic human pathogen is present in the plant.”

As a chemical physicist working in Wilmington, Ragone got to know Kniel and Bais through Delaware’s scientific community and lab equipment sharing. A relationship built over time, culminating when Kniel, Bais, and Ragone applied for and received research funding from a Delaware Biotechnology Institute Center for Advanced Technology (CAT) grant for scientific technology and intellectual property.

The researchers married their interdisciplinary expertise to reduce the risk of foodborne illness, a task that industry and academic researchers struggled with for many years. The result? The team created a multi-spectral imaging platform to look at plant sentinel response. A goal is to use this technique directly on a conveyor, scanning your lettuce before it ever heads to the grocery store.

So how do you see a symptom that you can’t see? The researchers’ technique scans leaves via multispectral imaging and deep UV sensing when the plant is attracting these pathogens. When the researchers looked at benign bacteria, they observed little change. But, with harmful, human-borne pathogens, the test can spot differences in the plant under attack.

“Using listeria as an example, in three to six hours, we see a sharp drop of chlorophyll pigments,” Bais said. “That’s a strong signal that the plant is responding physiologically — a marker of unusual bacteria.”

The new, multi-spectral imaging technique is non-invasive, and lightning-fast compared to current tests, where a lab scientist extracts a leaf, grinds it up, plates the bacteria, and looks for disease. The current method is not commercially available, but Biospection was awarded a National Science Foundation Small Business Innovation Research grant in 2022 to develop and commercialize it into a real-time imaging sensor to inspect plants for disease and other stresses.

“Harsh and Kali were certainly instrumental in the techniques that we developed with multi-spectral imaging and the use of deep ultraviolet fluorescence,” said Ragone, founder and chief technology officer of Biospection. “We built a portable instrument that could be commercialized.”

Vertical farming is an agricultural sector that stands to reap the benefits of this new technology. Using less water and less space, vertical farms are a vital step towards more sustainable agriculture. But when it comes to disease, these farms are just as vulnerable as traditional, outdoor agriculture. An incidence of E. coli means a vertical farm must throw away an entire harvest.

Biospection is already working with agricultural companies to embed the imaging sensor into vertical farms’ shelves and, for outdoor farms, crop drones.

“Working with UD, we’ve laid the scientific foundation to create better instruments,” Ragone said. “We’re working toward an instrument that’s portable, automated, and can give an answer in a matter of seconds.”

For future research, Bais has his eye on determining if this technology can differentiate between different microbes.

“If the sentinel response is different from one microbe to the other, that gives us the identity of the microbe based on plant sentinel response. We haven’t gone there yet, but that would be the ultimate achievement,” Bais said. “In one sentinel, then you could differentiate between what benign and harmful microbes does this in terms of one sentinel.”

Reference: “Deep ultraviolet fluorescence sensing with multispectral imaging to detect and monitor food-borne pathogens on the leafy green phyllosphere” by Nick Johnson, Kalmia Kniel, Harsh Bais and Anthony Ragone, 16 April 2023, Journal of Food Safety.
DOI: 10.1111/jfs.13056

University of Delaware

Microbiology

Here’s why your freezer smells so bad – and what you can do about it

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Most people would expect a freezer can keep perishable food fresh and safe from spoilage for many months. Unfortunately, this is not always the case.

Have you ever noticed a funky smell in your freezer? Where does it come from and what can be done to fix the problem?

There are several causes for bad smells coming from your freezer. Typically, the culprits are microbes – bacteria, yeasts and moulds.

Although a freezer dramatically slows down the growth of most common spoilage microbes, some can still thrive if the temperature rises above -18℃ (the recommended freezer temperature). This can happen if there is a power outage for more than a few hours, or if you put something hot straight in the freezer.

Food spills and open containers provide an opportunity for microbes to get to work. It’s also worth noting that many microbes will survive freezing and start growing again once conditions are favourable – for example, if you remove the food, partially thaw it, and return it to the freezer.

Two things happen when food breaks down. First, as microbes start to grow, several pungent chemicals are produced. Second, the fats and flavours that are part of the food itself can and will be released.

These are generally referred to as volatile organic compounds (VOCs). They are the pleasant aromas that we sense when we eat, but VOCs can also be produced by bacteria.

For example, many of us would be familiar with the smells that come from fermentation – a microbial process. When fermenting a food, we intentionally contaminate it with microbes of known characteristics, or provide conditions that favour the growth of desirable microbes and subsequent production of aromatic compounds.

By contrast, uncontrolled food spoilage is problematic, especially when the contaminating microbes can cause disease.

It is not only microbial growth that can lead to undesirable odours. There’s a suite of chemical processes happening in the freezer, too.

Freezing causes physical changes to foods, often enhancing their breakdown. Many of us would be familiar with “freezer burn” on meats and other foods, as well as ice crystals on frozen food.

This phenomenon is called “salt rejection”. Depending on how rapidly something is frozen, salts can sometimes be concentrated, as pure water freezes at a higher temperature than water with things dissolved in it – like sugars and salts. On a large scale, this happens to icebergs in the ocean. As the sea water freezes, salt is removed. Thus, the iceberg is composed of fresh water, and the surrounding sea water becomes a saltier and denser brine.

In a similar way, as water in food freezes, organic molecules are concentrated and expelled. If these are volatile, they move about the freezer and stick to other things. Where they end up depends on what else is around.

Some of the volatiles like water. We call them “hydrophilic” or water loving; those are the ones that will make your food taste bad. Other are more water-hating or “hydrophobic” and they stick to things like silicone ice cube trays, making them go smelly.

Domestic freezers are commonly attached to a refrigerator, and this provides another opportunity for smells to move through the systems. The two units share a single cooling source and airflow channel. If your fridge has foul odours from the food inside (natural or after microbial spoilage), it is very likely they will migrate to your freezer.



Read more:
How colour-coding your fridge can stop your greens going to waste

There are some simple steps you can take to stop your freezer from smelling.

First, try to prevent odours from developing in the first place by covering the food. If you place food in an airtight container (glass is best), it will dramatically slow the release of any aromatic compounds produced by bacteria or the food itself. Covered food is also less likely to absorb smells and flavours from other foods around it.

If the smells have already developed, you can eliminate them by following a few simple steps, including a thorough clean.

If the smells are not removed with these simple cleaning steps, the freezer may require a deep clean, which involves turning off the unit and letting it “breathe” for a few days.

Placing some baking soda inside the freezer before adding food can help to absorb any residual odours. For serious smells where crevices or insulation are contaminated, you may need a service technician.

In short, even though we think freezers keep things “fresh”, microbes can still proliferate in there. Make sure to clean your freezer now and then to keep your food safe and healthy.


Enzo Palombo


Rosalie Hocking

The Conversation

Microbiology

The Great Chocolate Crisis: How Swift Action Halted a Salmonella Epidemic

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Avoiding a global chocolate disaster – how tracing and recalls avoided a worldwide Salmonella outbreak.

Largest ever recall of chocolate products in global history, just before Easter, prevented thousands of extra cases; a total of 455 cases of Salmonella Typhimurium found in 17 countries; UK had most cases with 128.

Like any other manufactured food product, chocolate can be contaminated if key ingredients or processes break down. In a presentation at a pre-ECCMID day for this year’s European Congress of Clinical Microbiology & Infectious Diseases (ECCMID 2023, Copenhagen), Dr. Johanna Takkinen, Principal Expert for Food- and Waterborne Diseases at the European Centres for Disease Control and Prevention (ECDC), Stockholm, Sweden, will discuss the drama as the story unfolded, and the lessons learned from an outbreak of Salmonella Typhimurium in Kinder Chocolate Eggs traced to a Belgian chocolate factory.

”If not for clear and coordinated action across Europe and beyond, there may have been many thousands more children falling ill, and potentially many deaths,” says Dr. Takkinen.

Authorities in the UK (the UK Health Security Agency [UKHSA]) first raised the alarm in ECDC-hosted alert platform EpiPulse on 17 February 2022, reporting a cluster of 18 children reported ill with monophasic Salmonella Typhimurium infections since January 2022. Of these, seven were hospitalized and five of the seven had bloody diarrhea, a serious symptom. “Preliminary interviews of first cases indicated Kinder chocolate products as a possible vehicle of infection. Several countries then began reporting an increasing number of infections with strains the same as the UK outbreak,” explains Dr. Takkinen. By February 18, France had reported its first 2 cases, and by 18 March 59 cases were reported in five countries.

Late in March 2022, ECDC coordinated a teleconference with affected countries when four non-human monophasic S. Typhimurium isolates, genetically close to the human isolates, were identified in a public database. Within a week, these isolates were confirmed as originating from one particular Belgian chocolate factory. Prior to this, identifying which factory or factories were involved was difficult since there are four factories within the European Union that produce Kinder chocolate in large quantities. This new microbiological evidence allowed the various agencies to focus their investigations on one factory.

Meanwhile, the Food Standards Agency (FSA) in the UK and the Food Safety Authority (FSA) in Ireland and the UK FSA decided to recall, on April 2, certain Kinder Chocolate products (including Kinder Surprise Eggs). On April 8 authorities, now confident the factory was identified, ordered that chocolate factory (Ferrero) closed, and two days later had issued a global recall of products from the factory. The alert reached 130 countries, and in addition to the 401 cases identified in the EU and UK combined (the UK had the most cases, with 128), further cases were identified in Switzerland (49) and Canada (4) and the USA (1) – giving a global total of 455 cases in 17 countries. The ECDC and EFSA also published Rapid Outbreak Assessments to keep the public updated.

Children under 10 years old made up most of the reported cases (86%), and around two-thirds (61%) were female. A number of adults (27), most aged 21-40 and women (18 of the 27), were also infected. Among these adults were a handful of men and women in the age groups 41-70 years. Of 349 analyzed cases, 28% were serious enough to be hospitalized, with many experiencing symptoms such as bloody diarrhea. Of 179 cases interviewed (mostly via family members), 170 (95%) reported eating types of Kinder chocolate products there that were produced in the implicated Belgian factory.

Testing of multiple products from the factory resulted in 81 Salmonella positive samples, with two different strains, in the Belgian factory between December 3, 2021 and January 25, 2022 (most by PCR). The authorities estimated that the original contamination event happened before December 2021; one final product was positively identified as contaminated with Salmonella on December 3, and the first case with symptom progression was on December 12. Due to the time taken to move from production to retail sites, the majority of early cases began to appear in January 2022. The tank for anhydrous milk fat (known as buttermilk) were identified as hot spots for contamination, with the anhydrous milk fat coming from a factory in Italy that tested negative for Salmonella. The Ferrero factory went through several rounds of cleaning and disinfection before being reallowed to open on June 17, 2022, for three months with conditions, but having its permanent license for production reissued on September 17, 2022.

Dr. Takkinen says: “Children were at very high risk in this outbreak, with several chocolate products but mostly chocolate eggs affected leading up to Easter. Only through intensive collaboration with multidisciplinary teams of public health experts (microbiologists, epidemiologists) and regular cross-sectoral communication (public health – food safety) were authorities able to prevent a devastating global outbreak.”

She adds: “Also crucial in preventing the escalation of the outbreak was the effective early detection of cases through Salmonella surveillance in the UK, and the early verification of a rapidly evolving multi-country outbreak thanks to prompt responses by countries.”

Meeting: ECCMID 2023

European Society of Clinical Microbiology and Infectious Diseases

Microbiology

Warning: Study Finds Superbugs Lurking in 40% of Supermarket Meat

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“Superbugs” present in chicken, turkey, beef and pork, Spanish study finds.

Multidrug-resistant E. coli were found in 40% of supermarket meat samples tested in a Spanish study. E. coli strains capable of causing severe infections in people were also highly prevalent, this year’s European Congress of Clinical Microbiology & Infectious Diseases (ECCMID 2023, Copenhagen, April 15-18) will hear.

Antibiotic resistance is reaching dangerously high levels around the world. Drug-resistant infections kill an estimated 700,000 people a year globally and, with the figure projected to rise to 10 million by 2050 if no action is taken, the World Health Organization (WHO) classes antibiotic resistance as one of the greatest public health threats facing humanity.

Multidrug-resistant bacteria can spread from animals to humans through the food chain but, due to commercial sensitivities, data on levels of antibiotic-resistant bugs in food is not made widely available.

To find out more, Dr Azucena Mora Gutiérrez and Dr Vanesa García Menéndez, of the University of Santiago de Compostela-Lugo, Lugo, Spain, together with colleagues from other research centres, designed a series of experiments to assess the levels of multidrug-resistant and extraintestinal pathogenic Enterobacteriaceae (Klebsiella pneumoniae, E. coli and other bacteria that can cause multidrug-resistant infections such as sepsis or urinary tract infections) in meat on sale in Spanish supermarkets.

They analysed 100 meat products (25 each of chicken, turkey, beef and pork) chosen at random from supermarkets in Oviedo during 2020.

The majority (73%) of the meat products contained levels of E. coli that were within food safety limits.

Despite this, almost half (49%) contained multidrug-resistant and/or potentially pathogenic E. coli.  From those, 82 E. coli isolates were recovered and characterised. In addition, 12 K. pneumoniae isolates were recovered from 10 of the 100 meat products (7 chicken, 2 turkey and 1 pork).

Forty of the 100 meat products contained multidrug-resistant E. coli (56 of the 82 E. coli characterised). These included E. coli that produced extended-spectrum beta-lactamases (ESBLs), enzymes that confer resistance to most beta-lactam antibiotics, including penicillins, cephalosporins and the monobactam aztreonam.

The percentage of positive samples for the carriage of ESBL-producing E. coli per meat type was: 68% turkey, 56% chicken, 16% beef and 12% pork. This higher presence of ESBL-producing E. coli strains in poultry compared to other types of meat is likely due to differences in production and slaughter.

Twenty-seven per cent of the meat products contained potentially pathogenic extraintestinal E. coli (ExPEC).  ExPEC possess genes that allow them to cause disease outside the gastrointestinal tract. ExPEC causes the vast majority of urinary tract infections (UTIs), is a leading cause of adult bacteraemia (sepsis) and is the second most common cause of neonatal meningitis.

Six per cent of the meat products contained uropathogenic (UPEC) E. coli – UPEC is part of the ExPEC group; these possess specific virulence traits that allow them to cause UTIs.

One per cent of the meat products contained E. coli harbouring the mcr-1 gene.  This gene confers resistance to colistin, an antibiotic of last resort used to treat infections caused by bacteria resistant to all other antibiotics.

The study’s authors, who in a previous study reported high levels of bacteria that were potentially capable of causing severe human infections and/or multidrug resistant in chicken and turkey1, say that their latest research shows that consumers may also be exposed to these bacteria through beef and pork.

They are calling for regular assessment of levels of antibiotic-resistant bacteria, including ExPEC E. coli, in meat products.

Dr Mora adds: “Farm-to-fork interventions must be a priority to protect the consumer. For example, implementation of surveillance lab methods to allow further study of high-risk bacteria (in farm animals and meat) and their evolution due to the latest EU restriction programmes on antibiotic use in veterinary medicine.

“Strategies at farm level, such as vaccines, to reduce the presence of specific multidrug-resistant and pathogenic bacteria in food-producing animals, which would reduce the meat carriage and consumer risk.

“The consumer plays a key role in food safety through proper food handling. Advice to consumers includes not breaking the cold chain from the supermarket to home, cooking meat thoroughly, storing it properly in the refrigerator and disinfecting knives, chopping boards and other cooking utensils used to prepare raw meat appropriately to avoid cross-contamination. With these measures, eating meat becomes a pleasure and zero risk.”

Reference: “Microbiological risk assessment of Turkey and chicken meat for consumer: Significant differences regarding multidrug resistance, mcr or presence of hybrid aEPEC/ExPEC pathotypes of E. coli” by Dafne Díaz-Jiménez, Isidro García-Meniño, Alexandra Herrera, Luz Lestón and Azucena Mora, 19 October 2020, Food Control.
DOI: 10.1016/j.foodcont.2020.107713

European Society of Clinical Microbiology and Infectious Diseases

Microbiology

Top 5 Health Benefits of Cinnamon: Heart, Diabetes, Inflammation, Weight Loss, Brain

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Cinnamon is a spice that has been used for centuries in traditional medicine and cooking. It is derived from the bark of several trees in the Cinnamomum family and is known for its warm, sweet flavor. In addition to its culinary uses, cinnamon is also known for its numerous health benefits. You can even find cinnamon in supplement form as capsules, often with the active molecule cinnamaldehyde in a concentrated form. In this article, you’ll learn the major ways in which cinnamon can improve your health.

Cinnamon has been shown to have a positive effect on cardiovascular health. Studies have found that it can help to lower blood pressure, reduce cholesterol levels, and improve blood sugar control. One study found that consuming just 120 milligrams of cinnamon per day for 12 weeks resulted in a significant reduction in blood pressure.[1]

Cinnamon contains antioxidants that can help to protect the heart from oxidative stress, which is a major contributor to heart disease. By reducing oxidative stress, cinnamon can help to reduce inflammation in the arteries. In turn, this improves blood flow and reduces the risk of heart attack and stroke.

Cinnamon has even been shown to reduce blood sugar in people with type 2 diabetes. According to a meta-analysis that synthesized the results of 10 studies, cinnamon in doses of 120 mg to 6 g per day effectively reduces fasting glucose levels in people with diabetes within 4 to 18 weeks.[2]

It works by increasing insulin sensitivity. Insulin is the hormone that regulates blood sugar levels. With greater insulin sensitivity, the body can use insulin more effectively. This could potentially help prevent or manage diabetes.

Inflammation is a natural response of the body to injury or infection, but when it becomes chronic, it can lead to a host of health problems, including arthritis, heart disease, and cancer. Cinnamon contains compounds that have anti-inflammatory properties, which can help to reduce inflammation in the body. Studies have shown that cinnamon can reduce the production of inflammatory molecules and inhibit the activity of inflammatory enzymes.[3]

Cinnamon can also help to reduce inflammation in the gut, which is important for maintaining gut health. By reducing inflammation in the gut, cinnamon can help to improve digestion, reduce bloating and gas, and prevent leaky gut syndrome.

Cinnamon can also help to support weight loss. By helping to regulate blood sugar levels, cinnamon can reduce cravings for sugary foods and help to prevent overeating. It can also boost your metabolism, which can help to burn more calories and promote weight loss. A meta-analysis that pooled results from 7 studies found that cinnamon supplementation reduces body weight and body mass index (BMI). It noted the results were more drastic in people who took more than 3 grams of cinnamon per day.[4]

Cinnamon has also been shown to have a positive effect on brain function. One study found that cinnamon can improve cognitive function, including memory and attention span.[5] Another study found that cinnamon can help to protect the brain against age-related decline by increasing the production of proteins that are important for brain health.[6]

Cinnamon can also help to improve mood by increasing the production of serotonin — a neurotransmitter that is important for regulating mood and preventing depression.

Cinnamon is a delicious spice that offers numerous health benefits. Whether you sprinkle it on your oatmeal, add it to your coffee, or use it in your cooking, cinnamon is a great way to give your body a boost. From improving heart health to fighting inflammation, supporting weight loss, and boosting brain function, there are many reasons to make cinnamon a part of your daily routine. Some supplements contain concentrated forms of the active molecule in a spice or herb. If you’re taking a cinnamon supplement, be sure to take no more than the amount recommended on the product’s label.

References:

SciTechDaily.com

Microbiology

Scientists Warn: Food Coloring Nanoparticles May Damage Human Gut

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According to a recent study by scientists at Cornell and Binghamton University, metal oxide nanoparticles which are frequently utilized as food coloring and anti-caking agents in the food industry, may cause damage to certain sections of the human intestine.

“We found that specific nanoparticles – titanium dioxide and silicon dioxide – ordinarily used in food may negatively affect intestinal functionality,” said senior author Elad Tako, associate professor of food science at Cornell. “They have a negative effect on key digestive and absorptive proteins.”

In their study, the research team administered human-equivalent doses of titanium dioxide and silicon dioxide in the Tako laboratory’s in vivo system, which provides a health response that closely resembles that of the human body.

The scientists injected the nanoparticles into chicken eggs. After the chickens hatched, the scientists detected changes in the functional, morphological, and microbial biomarkers in the blood, the duodenum (upper intestine), and the cecum (a pouch connected to the intestine).

“We are consuming these nanoparticles on a daily basis,” said Tako. “We don’t really know how much we consume; we don’t really know the long-term effects of this consumption. Here, we were able to demonstrate some of these effects, which is a key to understanding gastrointestinal health and development.”

Despite the finding, the scientists are not yet calling for an end to the use of these nanoparticles.

“Based on the information, we suggest simply being aware,” Tako said. “Science needs to conduct further investigations based on our findings. We are opening the door for discussion.”

Reference: “Food-Grade Metal Oxide Nanoparticles Exposure Alters Intestinal Microbial Populations, Brush Border Membrane Functionality and Morphology, In Vivo (Gallus gallus)” by Jacquelyn Cheng, Nikolai Kolba, Alba García-Rodríguez, Cláudia N. H. Marques, Gretchen J. Mahler and Elad Tako, 9 February 2023, Antioxidants.
DOI: 10.3390/antiox12020431

The study was funded by the National Institutes of Health.

Nanoparticles are used in food colorings to improve their stability, solubility, and color intensity. Food coloring nanoparticles are made by reducing the size of color particles to the nanoscale range, typically between 1 and 100 nanometers in diameter.

Nanoparticles have a larger surface area than larger particles, which makes them more reactive and improves their ability to disperse in food. This improved dispersion leads to better color stability, as the nanoparticles are less likely to clump together or settle out of the food product.

In addition to stability, nanoparticles can also enhance the intensity of food colors. This is because the smaller size of the particles allows them to interact more efficiently with light, resulting in more vivid and intense colors.

However, it is important to note that the use of nanoparticles in food has raised concerns about their potential health effects. As a result, regulatory bodies such as the U.S. Food and Drug Administration (FDA) require that food manufacturers provide evidence that the nanoparticles they use are safe for consumption.

Cornell University

Microbiology

Beware of Fungi in Flour: It Won’t Turn You Into a Zombie, but It Can Make You Sick

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Pancakes won’t turn you into a zombie as in HBO’s ‘The Last of Us,’ but fungi in flour have been making people sick for a long time.

In the HBO series “The Last of Us,” named after the popular video game of the same name, the flour supplies of the world are contaminated with a fungus called Cordyceps. When people eat pancakes or other foods made with that flour, the fungi grow inside their bodies and turn them into zombies.

As a food scientist, I study the effect of processing on the quality and safety of fruits and vegetables, including the flour used to make pancakes. While no one is going to turn into a zombie from eating pancakes in real life, flour is often contaminated with fungi that can produce mycotoxins that make people sick. Proper processing and cooking, however, can generally keep you safe.

‘The Last of Us’ is premised on a pandemic that brings the world to an apocalyptic collapse.

People have been eating bread made from wheat for approximately 14,000 years and cultivating wheat for at least 10,000 years. In 1882, “drunken bread disease” was first documented in Russia, where people reported dizziness, headache, trembling hands, confusion, and vomiting after eating bread. Long before that, Chinese peasants were reporting that eating pinkish wheat – a key sign of infection with a mold called Fusarium – caused them to feel ill. Clearly, fungi have been making people sick for a long time.

Wheat, corn, rice, and even fruits and vegetables can be infected with fungi as they grow in the field. In “The Last of Us,” an epidemiologist theorizes that climate change is causing the fungus to mutate so it can infect humans. The unfortunate reality is that fungi have become more of a problem in recent years as warmer temperatures encourage their growth.

A 2017 study found that over 90% of wheat and corn flour samples in Washington, D.C., contained live fungi, with Aspergillus and Fusarium the predominant types of mold in wheat flour. Fusarium grows on wheat in the field and can cause a common agricultural plant disease called fusarium head blight, or scab.

Farmers use multiple techniques to reduce this devastating plant disease, including implementing crop rotation, using resistant varieties and fungicides and minimizing irrigation during flowering. After harvesting, they sort the grains to remove contaminated wheat before grinding them into flour. While sorting removes most of the contaminated wheat, small amounts of fungi can still make it into the flour.

The good news is that most fungi and other microorganisms die at 160-170 degrees Fahrenheit (71-77 degrees Celsius). Pancakes are typically cooked to an internal temperature of 190-200 °F (88-93 °C). Other cakes and breads are cooked to internal temperatures anywhere from 180 to 210 degrees Fahrenheit (82-99 °C). So, unlike in “The Last of Us,” as long as you bake or fry your dough, you’ll have killed the fungi.

The problem comes when people eat the flour without cooking it first, such as by consuming raw cookie dough or “licking the bowl clean.” Both raw egg and raw flour can contain microorganisms that make people sick. The microorganisms that public health officials are most worried about are E. coli and Salmonella, dangerous pathogens that can cause severe illness.

Most people don’t realize that the flour they buy at the store is raw flour that still contains live microorganisms. Flour is rarely commercially treated to be safe to eat raw because consumers almost always cook flour-based foods. While consumers can also attempt to heat-treat raw flour at home, this isn’t recommended because the flour may not be spread thinly enough to kill all of the microorganisms.

Some fungi and microorganisms can create spores, which are like seeds that help them survive adverse conditions. These spores can survive cooking, drying and freezing. There are even 4,500-year-old yeast spores that have been reawakened and made into bread. These fungal spores rarely cause serious illness in people, except in those with weakened immune systems.

Chemicals can be added to food to stop fungal growth. These additives include sorbates, benzoates and propionates. However, you almost never see these additives in flour or pancake mix because fungi can’t grow in a dry powder. The fungi either grew on the wheat in the field or on the bread after it is baked. For that reason, you may see these additives in bread but not in a powdered mix.

The biggest risk from fungi is not that it will grow inside our bodies, but that it will grow on wheat or other foods and produce chemicals called mycotoxins that can cause severe health problems. When wheat is harvested and ground into flour, mycotoxins can get mixed in.

Unfortunately, while normal cooking can kill the microorganisms, it doesn’t destroy the mycotoxins. Eating mycotoxins can cause problems ranging from hallucinations to vomiting and diarrhea to cancer or death. Some of the common mycotoxins found in grain include aflatoxins, deoxynivalenol, ochratoxin A and fumonisin B.

The oldest known case of mycotoxin poisoning is recorded as a disease called ergotism. Ergotism was mentioned in the Old Testament and has been reported in Western Europe since A.D. 800. It has even been suggested that the Salem witch trials were caused by an outbreak of ergotism that led its victims to hallucinate, though many have disputed this idea. Wheat is less likely than other grains to have dangerous mycotoxins, which is why some have proposed that declining mortality in 18th-century Europe, especially in England, was due to the switch from a rye-based diet to a wheat-based diet.

Ultimately, you don’t need to worry about eating those pancakes. Farmers use many techniques to minimize fungal growth and remove moldy grain, and the government keeps a close eye on mycotoxin levels during crop production and storage. Just make sure you cook your bakery products before eating, and don’t eat anything that has started to mold.

Written by Sheryl Barringer, Professor of Food Science and Technology, The Ohio State University.

This article was first published in The Conversation.The Conversation

Sheryl Barringer, The Ohio State University

Microbiology

Coffee + Milk: A Dynamic Duo for Fighting Inflammation

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Can something as simple as a cup of coffee with milk have an anti-inflammatory effect in humans? Apparently so, according to a new study from the University of Copenhagen. A combination of proteins and antioxidants doubles the anti-inflammatory properties in immune cells. The researchers hope to be able to study the health effects on humans.

Whenever bacteria, viruses, and other foreign substances enter the body, our immune systems react by deploying white blood cells and chemical substances to protect us. This reaction, commonly known as inflammation, also occurs whenever we overload tendons and muscles and is characteristic of diseases like rheumatoid arthritis.

Antioxidants known as polyphenols are found in humans, plants, fruits, and vegetables. This group of antioxidants is also used by the food industry to slow the oxidation and deterioration of food quality and thereby avoid off flavors and rancidity. Polyphenols are also known to be healthy for humans, as they help reduce oxidative stress in the body that gives rise to inflammation.

But much remains unknown about polyphenols. Relatively few studies have investigated what happens when polyphenols react with other molecules, such as proteins mixed into foods that we then consume.

In a new study, researchers at the Department of Food Science, in collaboration with researchers from the Department of Veterinary and Animal Sciences, at the University of Copenhagen investigated how polyphenols behave when combined with amino acids, the building blocks of proteins. The results have been promising.

“In the study, we show that as a polyphenol reacts with an amino acid, its inhibitory effect on inflammation in immune cells is enhanced. As such, it is clearly imaginable that this cocktail could also have a beneficial effect on inflammation in humans. We will now investigate further, initially in animals. After that, we hope to receive research funding which will allow us to study the effect in humans,” says Professor Marianne Nissen Lund from the Department of Food Science, who headed the study.

The study will be published today (January 30) in the Journal of Agricultural and Food Chemistry.

To investigate the anti-inflammatory effect of combining polyphenols with proteins, the researchers applied artificial inflammation to immune cells. Some of the cells received various doses of polyphenols that had reacted with an amino acid, while others only received polyphenols in the same doses. A control group received nothing.

The researchers observed that immune cells treated with the combination of polyphenols and amino acids were twice as effective at fighting inflammation as the cells to which only polyphenols were added.

“It is interesting to have now observed the anti-inflammatory effect in cell experiments. And obviously, this has only made us more interested in understanding these health effects in greater detail. So, the next step will be to study the effects in animals,” says Associate Professor Andrew Williams of the Department of Veterinary and Animal Sciences at the Faculty of Health and Medical Sciences, who is also senior author of the study.

Previous studies by the researchers demonstrated that polyphenols bind to proteins in meat products, milk and beer. In another new study, they tested whether the molecules also bind to each other in a coffee drink with milk. Indeed, coffee beans are filled with polyphenols, while milk is rich in proteins.

“Our result demonstrates that the reaction between polyphenols and proteins also happens in some of the coffee drinks with milk that we studied. In fact, the reaction happens so quickly that it has been difficult to avoid in any of the foods that we’ve studied so far,” says Marianne Nissen Lund.

Therefore, the researcher does not find it difficult to imagine that the reaction and potentially beneficial anti-inflammatory effect also occur when other foods consisting of proteins and fruits or vegetables are combined.

“I can imagine that something similar happens in, for example, a meat dish with vegetables or a smoothie, if you make sure to add some protein like milk or yogurt,” says Marianne Nissen Lund.   

Industry and the research community have both taken note of the major advantages of polyphenols. As such, they are working on how to add the right quantities of polyphenols in foods to achieve the best quality. The new research results are promising in this context as well:

“Because humans do not absorb that much polyphenol, many researchers are studying how to encapsulate polyphenols in protein structures which improve their absorption in the body. This strategy has the added advantage of enhancing the anti-inflammatory effects of polyphenols,” explains Marianne Nissen Lund.

The research is funded by Independent Research Fund Denmark and conducted in collaboration with the Technical University of Dresden in Germany.

Polyphenol Facts

Reference: “Phenolic Acid−Amino Acid Adducts Exert Distinct 2 Immunomodulatory Effects in Macrophages Compared to Parent 3 Phenolic Acids” 30 January 2023, Journal of Agricultural and Food Chemistry.
DOI: 10.1021/acs.jafc.2c06658

University of Copenhagen

Microbiology

Viruses can infect cells, and take them over to produce more viruses. But can viruses serve as a …

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Viruses can infect cells, and take them over to produce more viruses. But can viruses serve as a source of nutrition? It seems that, yes, some aquatic microbes are able tocan consume viruses and use them as a source of energy that fuels the microbe’s growth. In new research reported in the Proceedings of the National Academy of Sciences (PNAS), investigators showed that a species of microbe called Halteria, which are ciliates that live in freshwater ecosystems around the world, can survive on a diet of viruses alone; the researchers termed this phenomenon “virovory.” The microbes can eat thousands, even a million particles of chloroviruses in a single day, the researchers found.

Image credit: Pixabay

Chloroviruses infect green algae, which eventually causes the microscopic algal cells to burst, releasing carbon and other elements that other microorganisms can use in a kind of recycling process. The carbon is thought to be retained in a layer of microbial soup, without moving up the food chain, noted senior study author John DeLong, an associate professor at the University of Nebraska–Lincoln.

But vivory, noted DeLong, could be helping carbon escape that cycle, and those tiny organisms may be having a big impact.

By taking a rough estimate of the number of viruses and ciliates in the volume of water there is, a massive amount of energy could be moving up the food chain, said DeLong, who estimated that in a small pond, ciliates could eat 10 trillion viruses every day. “If this is happening at the scale that we think it could be, it should completely change our view on global carbon cycling.”

DeLong had suspected that some microbes could use viruses as a form of nutrition that almost anything would want to eat. “They’re made up of really good stuff: nucleic acids, a lot of nitrogen and phosphorous,” he explained. Lots of organisms will consume anything they can, so “surely something would have learned how to eat these really good raw materials.”

To see whether any microbes had indeed started to eat viruses, he did a simple experiment. After collecting samples from a local pond, he added chlorovirus to droplets of water that contained microbes from the pond. After one day, he could see that Halteria used chlorovirus as a snack food; there were so many more Halteria that he was able to start counting them. This was happening as the chlorovirus level was dropping precipitously. In two days, there were 100 times fewer viruses, and Halteria cells were growing to be about 15 percent larger. Halteria that had no access to chlorovirus weren’t getting any bigger.

Another experiment confirmed that Halteria cells were eating the virus. The researchers labeled chlorovirus DNA green, then watched as an organelle in Halteria cells that were exposed to these chloroviruses began to turn green. The ciliates were eating the virus.

After collecting additional data, DeLong found that Halteria can convert about 17 percent of the chlorovirus mass they consume into a new mass of their own.

DeLong is planning to return to the pond as the weather warms to confirm that this is also occurring in nature.

Sources: University of Nebraska-Lincoln, PNAS


Carmen Leitch

Microbiology

More land is used to grow wheat than any other crop, and wheat is a common cereal that’s …

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More land is used to grow wheat than any other crop, and wheat is a common cereal that’s eaten around the world. Wheat is estimated to provide about 18 percent of the food calories that people around the world need every day. Now researchers are warning that fungi pose a growing threat to wheat, a critical part of our food supply. Nearly half of the wheat crops in Europe are already affected by fungal infections that can generate toxic compounds called mycotoxins, according to new research in Nature Food.

Image credit: Pexels/Pixabay

Fungi can cause a disease called Fusarium Head Blight, which affects cereals. If people or animals eat cereals that are contaminated by mycotoxins, it may cause gastrointestinal issues like vomiting. Mycotoxins also have an economic impact, and lower the value of the crops they contaminate.

Both contaminated crops and Fusarium toxins are a serious concern, and pose a significant threat to our health, in part because we don’t fully understand how they affect our well-being, said study leader and fungal biologist Dr. Neil Brown of the University of Bath.

“But on top of these health concerns, we must remember that wheat is a hugely important global crop, so it’s essential for us to maintain high yields along with safe food production, not least because climate change, and now the war in Ukraine (the world’s fourth largest wheat exporter), are already impacting on wheat yields and grain prices.” It will be important to protect food security and maintain a stable wheat price, Brown added.

The researchers studied data on Fusarium mycotoxins in wheat that has been collected in Europe for the past decade. This showed that mycotoxins are present in wheat in every European country. More than half of the wheat in Europe that is grown for human consumption carries Fusarium mycotoxin, also known as “DON” or vomitoxin. Levels are higher in the U.K., where 70 percent of wheat is contaminated.

There are legal limits on DON levels in wheat that meant to be eaten by humans, and it’s estimated that 95 percent of the wheat that people consume does meet safety standards for DON levels. But the ubiquitous nature of the toxins revealed by this study has suggested that very low levels of mycotoxins might be found in people’s diets, and possibly for a very long time.

“There are real concerns that chronic dietary exposure to these mycotoxins impacts human health,” said Brown.

While there are mycotoxin limits for humans, animals seem to be eating high levels of DON mycotoxin. “It’s far higher than in human food. This is a concern for animal health, but it also paints a picture of what mycotoxin levels in food wheat could look like without current regulations,” noted first study author Louise Johns, a graduate student in the Brown group.

There is also a lot we still don’t know about Fusarium toxins. We don’t know why the levels of these toxins are increasing, although it may have to do with agricultural practices and climate change. We also still have more to learn about how the toxins interact with other chemicals, and how they affect human health.

The researchers noted that surveillance for mycotoxins should increase. Not all wheat is tested regularly, and this study also showed that 25 percent of the DON-contaminated wheat was also carrying other types of mycotoxins.

Sources: University of Bath, Nature Food


Carmen Leitch