I had this prof back in my undergraduate genetics days who prayed at the church of RNA.
He may have been right.
He was an asshole.
MicroRNAs are small RNA molecules that do not code for proteins, however, they take care of an essential function: they act as regulators in gene expression, and so they have become a focus of attention for medical science. Despite there being thousands of different sequences of this genetic material, the individual role that each one plays in several illnesses continues to be unknown for the most part.
Recently, research done at the University of Cordoba, among other places, and published in Nature Microbiology, was able to determine the specific function of certain microRNAs in Salmonella Typhimurium and Shigella flexneri infections. These are two similar bacteria that are passed on to humans upon ingesting food or water infected by people or animals with the disease.
These are two intracellular pathogens that invade healthy cells and cause similar symptoms. Nevertheless, in spite of their many similarities, the results show that infections from these two bacteria are controlled by different microRNAs that have a radically opposite function.
In order to come to this conclusion, an array of over 1,400 different microRNAs were studied individually so as to verify what effect they produce in cells upon being infected by these two bacteria, explains University of Cordoba Genetics Department researcher Sara Zaldívar.
In the case of Shigella, the results show that upon infection, three specific kinds of microRNA silence the expression of the gene responsible for spreading the bacteria within the infected organism by means of filaments called filopodia. This is an immune response mechanism of the infected organism that, as a result, lessens the bacteria’s movement.
In the case of Salmonella, almost the opposite occurs. Once the cell is infected, a kind of microRNA activates the expression of a gene responsible for the bacteria reproducing. This is the pathogen’s attack mechanism in order to reproduce, something that was not only demonstrated in the laboratory but also was corroborated in vivo in pig intestinal mucosa.
The results show two mechanisms of how microRNAs act in completely different ways and that were not described ever before. While in some infections, such as Shigella, these small molecules of genetic material perform a function in the immune response of the infected organism, in others, like Salmonella, they are part of the strategies developed by the bacterium to benefit itself in order to reproduce.
One of the main takeaways from the research, as pointed out by another author, Professor Juan José Garrido, is the need to understand the specific response mechanisms of each pathogen so as to not err by extrapolating treatment. “If we do not know exactly how microRNA regulation works, then we are blindly assigning treatment and we will end up haphazardly using a wide range of antibiotics that build up resistance to the bacteria”, says the researcher. “In our laboratory alone”, adds Sara Zaldívar, “we have strains of Salmonella that have built up resistance to 14 different antibiotics”. For this reason, knowing about the mechanisms of each pathogen in particular is key to developing more effective drugs by means of searching for target genes involved in the process.
Spaghetti alla carbonara is a traditional Italian dish, which the sauce made of raw egg yolks is heated using only the heat of cooked pasta. Concerns about the safety of this preparation have been raised due the possibility of egg yolks be contaminated by Salmonella and the heat treatment may not be sufficient for total Salmonella inactivation.
This study was undertaken to analyze the survival of Salmonella in spaghetti alla carbonara in which the only thermal processing of egg yolks was the heat transfer from the pasta. A pool of Salmonella was inoculated in egg yolks reaching 8.8 log10 CFU/g. Contaminated egg yolks were added to the cooked spaghetti, away from the heat source. Results indicated that immediately after cooking and draining, the pasta reached 86.0 °C. After 4.5 min of contact with the egg yolks, the mean temperature of spaghetti alla carbonara decreased to lower than 60 °C. The preparation method was able to inactivate approximately 4.7 log10 CFU/g of Salmonella and the spaghetti alla carbonara processed by this method had a creamy and silky sauce formed by yolks. Based on the results, it should be advisable the use of thermo-processed eggs to ensure the safety of this preparation.
Survival of Salmonella in spaghetti alla carbonara
During 2018–2019, CDC, local and state public health partners, the U.S. Department of Agriculture (USDA), and the Food and Drug Administration (FDA) investigated a multistate outbreak of 356 Salmonella Reading infections from 42 states and the District of Columbia (DC) linked to turkey. The outbreak strain was isolated from raw turkey products, raw turkey pet food, and live turkeys. In July 2018, CDC and USDA’s Food Safety and Inspection Service (FSIS) shared outbreak investigation results with representatives from the U.S. turkey industry, engaging with an industry group rather than a specific company for the first time during an outbreak, and CDC issued a public investigation notice. During the investigation, four recalls of turkey products were issued. Evidence suggested that the outbreak strain of Salmonella was widespread in the turkey industry, and therefore, interventions should target all parts of the supply chain, including slaughter and processing facilities and upstream farm sources.
In January 2018, through routine state surveillance, Minnesota Department of Health investigators identified four Salmonella Reading infections with an indistinguishable pulsed-field gel electrophoresis (PFGE) pattern, suggesting they likely shared a common source. One patient had consumed ground turkey, and two lived in the same household where pets in the home ate raw turkey pet food. Minnesota investigators also identified this same strain in one sample of retail ground turkey. This PFGE pattern is the most common subtype of Salmonella Reading; however, the Reading serotype is uncommon, not ranking in the 20 most common types of human Salmonella infections reported in the United States (1). In response to Minnesota’s investigation, PulseNet,* the national laboratory network for foodborne disease surveillance, was queried for additional Salmonella infections with this PFGE pattern. CDC began a multistate cluster investigation, collecting information on patient exposures from local and state health departments and information on food and pet food products from FDA and FSIS.
CDC defined a case as an infection with Salmonella Reading with the outbreak PFGE pattern with illness onset from during November 20, 2017–March 31, 2019. Patients were interviewed to collect information on consumption of turkey and other poultry foods, exposure to raw poultry pet food, and contact with live poultry.
Investigators from DC Health and the Iowa Department of Health identified two illness subclusters of cases in which attendees ate at a common event before becoming ill. The two events occurred in November 2018 and February 2019, and 152 persons became ill, including 51 whose clinical isolates matched the outbreak strain and 101 who had clinically compatible illness without culture confirmation of Salmonella infection. Investigators identified whole turkey and boneless roast turkey as the food items significantly associated with illness at these two events and found that turkey was not handled or prepared in accordance with FSIS guidelines and was not held at proper temperatures to prevent bacterial growth (2).
Overall, 356 outbreak cases from 42 states and DC were identified. Patients ranged in age from <1 to 101 years (median = 42 years), and 175 (52%) of 336 patients for whom information on sex was available were male. Among 300 patients with available information, 132 (44%) were hospitalized, and one died. Among 198 interviewed patients, 132 (67%) reported direct or indirect contact with turkey in the week before illness; 123 reported preparing or eating turkey products that were purchased raw (including whole turkey, turkey pieces, and ground turkey), four became sick after pets in their home ate raw ground turkey pet food, and five worked in a facility that raises or processes turkeys or lived with someone who worked in such a facility. No common type, brand, or source of turkey was identified.
During the investigation, the outbreak strain was identified in 178 samples of raw turkey products from 24 slaughter and 14 processing establishments in 21 states that were collected by FSIS as part of routine testing and in 120 retail turkey samples collected as part of the National Antimicrobial Resistance Monitoring System retail meat sampling program. These samples represented several brands and types of raw turkey products. The outbreak strain was also identified in 10 samples from live turkeys in several states.
Investigators from the Arizona State Public Health Laboratory and the Michigan Department of Agriculture and Rural Development identified the outbreak strain in two of three unopened ground turkey samples collected from two patient homes. These were the same brand of ground turkey but were produced in different facilities. Investigators from the Minnesota Department of Agriculture identified the outbreak strain in samples of two brands of raw turkey pet food that were served to pets in patients’ homes. No commercial connections or common source materials were identified among any of these facilities.
The two illness subclusters in this outbreak indicate improper handling and cooking of raw turkey products and highlight the need to reinforce consumer education. A 2017 study found that adherence to food safety practices among persons preparing turkey burgers was low but did improve after watching a USDA video on proper thermometer use (9). This same study also found very low adherence to CDC’s recommended steps for handwashing during food preparation and noted that approximately half of the participants contaminated other kitchen items, such as spice containers, by touching them while preparing turkey (9). These findings underscore the impact that food safety messaging can have on consumer behavior and the importance of proper food safety throughout the food preparation process. Consumers should always thaw turkeys safely (in the refrigerator in a container, in a leak-proof plastic bag in a sink of cold water, or in a microwave oven following the manufacturer’s instructions), avoid the spread of bacteria from raw turkey by keeping it separate from other foods and keeping food surfaces clean, and cook turkey to 165°F (74°C), measured on a food thermometer inserted into the thickest portions of the breast, thigh, and wing joint.† In addition to emphasizing the importance of food safety messaging, this outbreak reinforced the need for awareness of the recommendations against feeding pets a raw meat diet, which can lead to both human and animal illnesses (10). Finally, industries can take steps to provide consumer education through their marketing programs and on product packages. Consumers, public health agencies, and industry officials all play important roles in promoting and implementing Salmonella prevention and control strategies to prevent future illnesses.
The perceived risk of wild birds can impact their survival, said Olivia Smith, lead author on the study and a recent WSU Ph.D. graduate.
“Farmers are being encouraged to remove wild bird habitat to make their food safer, but it doesn’t appear that these actions are based on data,” Smith said. “When you restrict birds from agricultural settings, you are doing something that can lead to their decline.”
Bird populations have been falling rapidly in recent decades. Scientists estimate that since 1970, North America has lost more than three billion birds. In light of this, the WSU researchers highlighted the need for more definitive research before destroying habitat and banning birds from fields in the name of food safety.
Smith and her colleagues, WSU Associate Professor Jeb Owen and Professor William Snyder, analyzed data for E. coli, Salmonella and Campylobacter in 431 North American breeding bird species and found no relevant studies for 65% of those species, including birds that are commonly found in farm fields such as raptors, great blue herons and black-billed magpies.
In their review, the researchers found only one study definitively linking wild birds to food-borne illness outbreaks: a case where sandhill cranes spread Campylobacter on fresh peas in an outbreak that sickened nearly 100 people in Alaska in 2008.
The most studied birds in relation to these pathogens were ducks, geese as well as two non-native species, house sparrows and European starlings, that tend to swarm on feed lots and can contaminate the food and water used for cattle. Yet there’s a huge gap in knowledge about many other common native species that are often around agricultural crops including American robins.
Only 3% of the studies that the researchers analyzed looked at the entire transmission process from bird to plant to human. The majority simply tested bird feces to see if the bacteria were present or not.
In order for the bacteria to make people sick, the bird needs to get pathogenic strains of E. coli, Salmonella or Campylobacter on a food crop, and that bacteria has to survive long enough until people eat the contaminated food, including through shipment, washing, food processing in plants and food preparation. The data on the pathogen survival is also very limited.
“Birds do carry bacteria that can make people sick, but from our review of the scientific studies, it’s unclear how big of a risk they are,” Smith said.
Nopalina Flax Seed products are distributed throughout the United States and Puerto Rico via retail stores and the company’s website.
The recall is the result of a Food and Drug Administration sampling of senna leaves powder, an ingredient used to manufacture the Nopalina Flax Seed Fiber in capsule and powder form. The powder tested positive for three types of salmonella including salmonella gaminara, salmonella Kentucky and salmonella Oranienburg.
The company has ceased the use of the suspect ingredient, according to its Jan. 29 announcement on the FDA’s website.
Queensland, or maybe all of Australia, has banned single-use plastic bags at supermakets.
No biggie for me, I always have my knapsack.
But it would be more meaningful if Australian retailers could set aside their perverse fetish of wrapping every piece of cut fruit or veggie in plastic.
Fresh-cut presents unique risks and needs to be kept close to 4 C to limit microbial growth.
That ain’t happening at retail.
I have shared my evidence-based concerns with the supermarket, Coles, and they have done, nothing.
The U.S. Centers for Disease Control reports that on December 7, 2019, Tailor Cut Produce recalled its Fruit Luau cut fruit mix as well as cut honeydew melon, cut cantaloupe, and cut pineapple products because they have the potential to be contaminated with Salmonella.
These products were not sold directly to consumers in grocery stores.
These products were sold for use in institutional food service establishments such as hospitals, long-term care facilities, schools, and hotels.
Food service and institutional food operators should not sell or serve the recalled products.
The recalled fruit products were distributed between November 15 and December 1, 2019.
Twenty-seven hospitalizations have been reported. No deaths have been reported.
Since the last update on December 11, 85 additional ill people have been reported from 11 states.
These illnesses started during the same time period as the illnesses reported on December 11, but were not confirmed as part of the outbreak at that time.
Epidemiologic and traceback evidence indicate that cut fruit, including honeydew melon, cantaloupe, pineapple, and grapes, produced by Tailor Cut Produce of North Brunswick, New Jersey, is a likely source of this outbreak.
“Based on the slowed rate of human illness reports, the FDA and CDC are no longer recommending that people avoid purchasing or feeding pig ear pet treats entirely,” FDA officials wrote in a press release.
At the end of July, FDA and CDC recommended no pig ear pet treat sale or use in the United States. With the end of the outbreak, the FDA altered its guidance to pet product retailers and pet owners. The agency now recommends that retailers who wish to re-introduce pig ear pet treats should take appropriate steps to ensure that their suppliers are controlling for pathogens such as Salmonella, and that products are not cross-contaminated after processing. Likewise, the agency advised pet owners to use good hygiene when feeding pig ear pet treats.
Reports of illness from these Salmonella infections started on June 10, 2015 and ran until September 13, 2019. Over the course of the outbreak, official reports tied 154 cases of human infection with exposure to pig ear pet treats in 34 states. Patients ranged in age from less than one year to 90 years. Of 133 cases with info available, 35 people needed hospitalization. Children younger than 5 years were infected in 27 cases.
Public health officials conducted genome sequencing of the Salmonella involved in the outbreak. The researchers revealed that many of the strains were resistant to multiple antibiotics, including ampicillin, streptomycin, tetracycline and ciprofloxacin. Salmonella strains identified were Cerro, Derby, London, Infantis, Newport, Rissen and I 4,,12:i:-.
Three firms recalled product associated with the outbreak: Pet Supplies Plus, Lennox, and Dog Goods USA. A fourth firm, Hollywood Pet, also recalled Salmonella positive pet ear treats that it had sourced from Dog Goods USA, but testing was not sufficient to determine if these treats were connected to illnesses. All of these recalled products originated from suppliers in Argentina, Brazil and Colombia. The importers were placed on Import Alert 72-03 (“Detention Without Physical Examination and Intensified Coverage of Pig Ears And Other Pet Treats Due To The Presence of Salmonella”). These importers were Suarko, SRL (Argentina) and Anabe Industria e Comercio de Proteinas (Brazil), and Custom Pet S.A.S. (Colombia).
A catering firm that “spoiled” a couple’s wedding day with a salmonella-ridden hog roast has been ordered to pay nearly £250,000.
In total, 58 guests fell ill after tucking into the meaty centrepiece at Vicki and Phil Kemp’s reception.
The pair were so ill they had to cancel their Dominican Republic honeymoon, Cannock Magistrates’ Court heard.
Galloping Gourmet Ltd admitted two food safety offences, was fined £200,000 and ordered to pay £49,936 in costs.
Lichfield District Council, which identified the salmonella outbreak, described the contaminated meat as “dangerously undercooked”.
It added the firm had not taken customers’ health and safety seriously enough.
IT technician Mr Kemp, 35, of Burntwood, Lichfield, said in a statement: “My illness lasted around 10 days all in all, but the symptoms were so bad that we had no option but to cancel our honeymoon. I was totally devastated.
When I tell people lizards and snakes are Salmonella factories, they look at me like I’m hysterical.
Maybe they’ll listen to Scott Weese, a veterinary professor at the University of Guelph and author of the Worms and Germs Blog.
Weese writes, contact with reptiles such as geckos has been a known risk factor for human salmonellosis for years. That’s a big part of the reason for recommending that high risk people (i.e. those less than 5 years of age, over 65 years of age, pregnant, or immunocompromised) have no contact (direct or indirect) with reptiles.
In this outbreak (Koski et al, Zoonoses and Public Health 2019), Salmonella Fluntern was the cause of infection in 12 people in 4 US states (Oregon, California, Iowa and New York). The median age of those affected was 5 years, with a range from less than 1 to 58 years of age (so much for the “keep young kids away from reptiles” recommendation). No one died, but 3 people (25%) were hospitalized. Most people reported contact with leopard geckos, and the same bacterium was isolated from a gecko owned by one affected person.
No common source of geckos was identified and their bacteria were different enough genetically that a point source isn’t likely. Other gecko- or reptile-associated Salmonella Fluntern isolates were identified in bacterial databases from Europe. So, this suggests that Salmonella Fluntern is a reptile (or even gecko) associated strain, posing a broad risk to reptile/gecko owners.
This report doesn’t change any recommendations, but just shows (again) the issues that are involved. Reptiles shouldn’t be in high risk households. People with reptiles need to use some basic hygiene precautions to reduce their risk of infection. It’s not rocket science, but it’s often neglected.