Compost sounds cool, but is it food safety safe

Posted on May 28, 2020 by Douglas Powell

Twenty years ago, I sent one of my students to a big organic conference in Guelph, and requested that she ask one question: How do you know compost is microbiologically safe?

The answer was not convincing.

‘There’s so many good bacteria they out-compete the bad bacteria.’

Fairytale.

Ten years ago, I was visiting a colleague in Melbourne in his high-rise office and he said, see those crappy little houses down there with their crappy little backyard gardens, they provide the produce for Melbourne’s high-end restaurants, and it’s all fertilized with night soil’ (human shit).

A couple of days ago The Packer published a piece about composting food safety.

Doug Grant, who chairs the Center for Produce Safety’s Knowledge Transfer Task Force wrote that composting is a seemingly magical process that decomposes organic materials like green waste or animal manures through microbial fermentation, creating nutrient-rich amendments that can be added back to soils.

It’s not magical; it’s microbiological.

However, compost can also pose a risk to the food safety of fresh produce.

Animal manure is widely suspected to be a significant source of human pathogens. Cows can carry E. coli, while poultry and swine can carry Salmonella. If compost is made with manure containing such pathogens, and the composting process is not controlled properly, these pathogens can survive composting. Contaminated compost applied to fields can then cross-contaminate fresh produce that contacts amended soil during growth, irrigation or harvest.

Yes, we have over 20 years of evidence.

Gurmail Mudahar, Ph.D., is vice president of research and development and food safety at Tanimura & Antle and is a member of CPS’s technical committee and California Leafy Greens Marketing Agreement’s (LGMA) advisory board. He reports that his company used to prepare and apply their own animal manure-based composts. That changed when food safety emerged as a major leafy greens industry issue almost two decades ago.

Then Tanimura & Antle and other growers began buying compost only from specialized manufacturers to minimize produce safety hazards.

At its simplest, composting is a manufacuring process. To produce compost safely, the most critical controls are high temperature and time held at that temperature. Over time, the heat generated by microbial respiration in turn reduces the compost’s microbial population, including any human pathogens present.

As a general rule, compost temperatures must reach 131 degrees Fahrenheit or 55 degrees Celsius for 3-15 days, followed by a curing phase of least 21 days and preferably a few months. (Once applied to agricultural fields, pathogens continue to die off when exposed to sunlight’s ultraviolet rays, humidity, temperature, time and other factors.)

Use a thermometer and stick it in.

UK dad left paralyzed after developing suspected food poisoning on dream holiday

Posted on May 26, 2020 by Douglas Powell

Cathy Owen of Wales Online writes a dad-of-three has been left paralysed after developing suspected food poisoning on a dream holiday to celebrate his 25th wedding anniversary.

William Marsh, from Mountain Ash, was in a coma for 10 weeks and spent seven months in hospital after becoming ill on a holiday to the Dominican Republic with his wife Kathyrn two years ago.

The 57-year-old has been diagnosed with the rare condition Guillain-Barré syndrome, a serious neurological condition which is a known complication from food poisoning.

He has now called on specialist serious injury lawyers to investigate his “devastating” ordeal.

William started suffering from stomach cramps and diarrhoea towards the end of a week-long all-inclusive at the Riu Naiboa resort which was booked to celebrate his 25th wedding anniversary.

When he got back home to Wales, the symptoms continued and on the day he was due to return to work as an engineer he woke up to find he had no feeling in his legs.

That sensation then started to spread across his entire body and William was diagnosed with Guillain-Barré syndrome.

William said: “Kathryn and my daughter fell ill first and then it hit me. The symptoms were awful but we just tried to push through it. I needed to get myself to work, so I thought nothing of it really.

“But then I got a huge shock when I woke up one morning and couldn’t feel my legs.”

William was on a ventilator in Prince Charles Hospital in Merthyr Tydfil and after a long period of treatment he was able to return home. But his life has now changed massively.

Almost two years on from his diagnosis, the father-of-three still cannot walk and is essentially confined to his living room due to the extent of his needs. He has been unable to return to work.

Guillain-Barré syndrome (GBS) is an autoimmune condition affecting the peripheral nervous system.

Often triggered by a viral or bacterial infection such as flu or food poisoning, it causes the nerves in the arms and legs to become inflamed and stop working, usually leading to temporary paralysis which may last from a few days to many months.

An estimated 1,300 people (one to two people per 100,000) are affected by GBS annually in the UK. About 80 per cent will make a good recovery, but between five and 10 per cent of people will not survive and 10-15 per cent may experience long term residual effects ranging from limited mobility or dexterity, to life-long dependency on a wheelchair.

Organic basil recalled due to Cyclospora risk

Posted on May 17, 2020 by Douglas Powell

I keep telling people that certain fresh herbs – like basil – are a ridiculously high percentage of foodborne illnesses.

They look at me like I just fell off the truck.

Sure, I walk with a cane now because I fall too much, but not off trucks.

United Natural Foods, Inc. (UNFI) is initiating a voluntary recall of a limited quantity of Wild Harvest® Organic Basil distributed out of UNFI’s Hopkins, MN distribution center to select retailers in Minnesota between 4/18/2020-5/8/2020. UNFI’s recall is issued out of an abundance of caution because of the potential for the impacted product to be contaminated by Cyclospora cayetanensis. No illnesses, including allergic reactions, involving this product have been reported to date.

This recall includes Wild Harvest® Organic Fresh Basil products sold in .25oz, .75oz, 2oz, and 4oz plastic clam shell containers (UPCs: 0071153550450, 0071153550322, 0071153550762, 0071153550323). Impacted product can be identified by a white sticker with black ink on the back of the container stating: “Product of Colombia” and “112.”

This concern was identified following routine sampling. Cyclospora cayetanensis is a microscopic parasite that can cause an intestinal illness in people called cyclosporiasis. According to the U.S. Centers for Disease Control and Prevention, the illness is usually not life threatening. Symptoms of cyclosporiasis may include: watery diarrhea (most common), loss of appetite, weight loss, cramping, bloating, increased gas, nausea and fatigue. Other symptoms that may occur but are less common include vomiting and low-grade fever.

New freeze-resistant trichinella species discovered

Posted on May 7, 2020 by Douglas Powell

Kim Kaplan of USDA’s Agricultural Research Service writes a new freeze-resistant Trichinella species has been discovered in wolverines by Agricultural Research Service scientists and their colleagues. Trichinella are parasites that cause the disease trichinosis (formally referred to as trichinellosis), which people can get by eating raw or undercooked meat from infected animals.

Before the advent of modern biosafety practices, Americans risked infection from Trichinella spiralis from contaminated pork. Residual risk exists when consuming wild game infected with this, or other species of Trichinella.

Freezing pork for three days generally kills T. spiralis but will not kill freeze-resistant varieties endemic to the Arctic. This study indicates freeze-resistance in this newly discovered species.

This is the first species of Trichinella discovered since 2012, and the 13th species identified since the genus was discovered in 1835.

The new species, now named Trichinella chanchalensis (and nicknamed “oddball”), was found in 14 of 338 wolverine samples tested. About 70 percent of the wolverine samples were infected by some Trichinella species. The samples were all provided by Canadian authorities that oversee trappers and/or game meat food safety in that country.

Wolverines, the largest member of the weasel family, are found mostly in northern Canada, Alaska, Nordic countries in Europe and throughout western Russia and Siberia.

“They make an excellent sentinel species to help us understand the scope of Trichinella in the environment,” said ARS research zoologist Peter Thompson who led the study. “A wolverine can have a home range of about 1,000 miles and will eat just about anything it can kill or scavenge, including caribou, moose, ground squirrels and other rodents as well as carnivores such as foxes and even other wolverines.” Thompson is with the ARS Animal Parasitic Diseases Laboratory in Beltsville, Maryland.

When the researchers first saw the new freeze-resistant Trichinella, they sought to understand if there had been interbreeding between T. nativa and T6, another freeze-resistant variety that is closely related to T. nativa.

By sequencing the newly discovered Trichinella species’ complete genome, it was shown that its DNA is about 10 percent different from any other Trichinella. By comparison, human and chimpanzee DNA only differ by 1 percent.

“Evolutionarily, the evidence shows that Trichinella chanchalensis split off from the other known Trichinella species about 6 million years ago, making it a very old species among Trichinella,” Thompson said. “That brings up the question of how T. nativa and T6 got their freeze resistance. Did the trait evolve more than once or is there some other mechanism at work?”

The ARS Animal Parasitic Diseases Laboratory, which is part of the Beltsville Agricultural Research Center, has a long history of helping provide the scientific basis for regulations that in the past ensured cured and cooked pork products were safe and reliable. Some of the lab’s accomplishments include:

Discovered that Trichinella can be reduced in pork by proper freeze methods, leading to new, effective meat inspection control measures in the first decade of the 20th century.

Established the standards for using salt, moisture, pH and temperature to effectively treat fermented, dry-cured pork sausage for Trichinella.

Assisted in the development of the best management practices for raising pigs to essentially eliminate the chances of domestic pork being infected with Trichinella.

Created the Polymerase Chain Reaction (PCR) test to specifically identify Trichinella species using a small DNA sample.

This research was published in the International Journal for Parasitology (https://doi.org/10.1016/j.ijpara.2020.01.003)

The Agricultural Research Service is the U.S. Department of Agriculture’s chief scientific in-house research agency. Daily, ARS focuses on solutions to agricultural problems affecting America. Each dollar invested in agricultural research results in $20 of economic impact.

Tularemia in muskrats: Long Point, Ontario (that’s in Canada)

Posted on May 7, 2020 by Douglas Powell

For a Brantford kid, Port Dover on the glimmering shores of Lake Erie was the closest beach; but for the full Lake Erie experience, we would drive a little further west to Long Point.

My friend Scott Weese, who is apparently treating the lock-down like I do, by writing more because ya don’t have to waste time at stupid meetings or commuting, writes in his Worms and Germs Blog that a recent report from the Canadian Wildlife Health Cooperative (CWHC) describes an outbreak of tularemia in muskrats in Long Point, Ontario. Tularemia is a potentially nasty disease caused by the bacterium Francisella tularensis. While not many people have contact with muskrats or live in Long Point, it’s still noteworthy.

The investigation was initiated following a report of at least 35 sick or dead muskrats in the area. Necropsies were done on some of the rodents, and they were found to have enlarged lymph nodes and lesions in their spleens and livers. Testing at the National Microbiology Laboratory identified Francisella tularensis. This was done at the national lab because F. tularensis is a containment level 3 pathogen requiring enhanced biosafety practices – so it’s not a bacterium which regular labs handle.

This isn’t a new finding, since we know this bacterium is present in Ontario, but it’s rare. Francisella tularensis is sporadically found in various animals and rarely in people (there’s been one reported human case in Ontario so far in 2020). It’s a reportable disease in animals and people because of the potential severity of infection, and because it’s a potential bioterrorism agent.

Back to the muskrats… tularemia is a rare finding in wildlife. That doesn’t mean it doesn’t cause disease, since sporadic disease in wildlife rarely gets investigated. It’s most commonly associated with rabbits, and human and domestic animal infections can be associated with rabbit or rodent contact. The fact that this occurred as an outbreak with a significant number of animals affected over a short period of time is interesting, and it’s also concerning from human and animal health standpoints. The bacterium can be spread in a variety of ways, including direct contact, inhalation (e.g. running over an infected animal with a lawnmower and aerosolizing the bug and then breathing it in… gross but true) and via some insects (e.g. ticks, deer flies).

Tularemia avoidance measures are pretty basic:

Avoid contact with wildlife, live or dead.

People handling dead wildlife, especially those handling them closely such as trappers, should use good routine hygiene and infection control practices.

Avoid ticks. For pets, that involves use of a good tick preventive. For the rest of us, well… we don’t have a chewable tick preventive but we can do other things to reduce the risk of tick exposure, including (and most importantly) doing “tick checks” if you’ve been outside in an area where ticks are likely to be lurking.

Keep your pets under control, especially if they are prone to chasing wildlife or snacking on dead animals (also gross but true).

The CWHC warning is pretty similar to my comments: “During an outbreak situation, it is presumed that bacterial levels would be higher in the surrounding environment, so caution is warranted for anyone who is traversing through the area or wading into the water in the Crown Marsh area of Long Point. There is also a danger to off-leash dogs as they can become infected and develop similar symptoms to humans, especially if they consume infected meat. It is recommended that dogs are kept on leash and monitored closely while in this area. It is recommended that people do not handle wildlife found dead unless they are wearing protective gloves (or a similar protective barrier) to prevent direct contact of the animal with the skin. Anyone who handles dead wildlife (even while wearing the appropriate protective gear) should wash their hands thoroughly to minimize the chances of exposure.”

A related topic that applies to animals and people is talking to healthcare providers about travel. The risk for various diseases differs geographically. A disease might not be on a physician’s or veterinarian’s list of considerations if they don’t know about travel. So, physicians and veterinarians need to query travel history, and everyone needs to remember that travel means going somewhere else, regardless where it is (even if they haven’t left the province).

Here’s a scenario that highlights that:

Me: Have you traveled with your dog lately?

Owner: No.

Me: Do you have a cottage?

Owner: Yes, it’s a beautiful place a couple of hours from here. We go there every weekend in the summer.

Me: So, you travel with your dog every weekend in the summer?

Owner: Well, that’s not travel, it’s going to the cottage.

Me: Ok, now let’s talk about the different things I need to consider now that I know your dog travels.

That’s not an unusual situation. Understanding where people and animals have been is important when thinking about infectious disease risks. Veterinarians and owners need to clearly communicate to identify potential problems.

Brucellosis and raw milk, again

Posted on May 1, 2020 by Douglas Powell

In December 2018, the Pennsylvania Department of Agriculture (PDA) and Pennsylvania Department of Health (PADOH) were notified of a New York patient with brucellosis caused by infection with Brucella abortus RB51, the live attenuated vaccine strain of B. abortus used to prevent brucellosis in cattle (1). Brucellosis is a serious zoonotic infection caused by the bacteria Brucella spp. The most common sign is fever, followed by osteoarticular symptoms, sweating, and constitutional symptoms (2). Without proper treatment, infection can become chronic and potentially life-threatening (2).

The patient had consumed raw (unpasteurized) milk from dairy A in Pennsylvania.* In July 2017, Texas health officials documented the first human case of domestically acquired RB51 infection associated with raw milk consumption from a Texas dairy (3). In October 2017, a second RB51 case associated with raw milk consumption was documented in New Jersey^†; the milk source was not identified at the time.

To determine the RB51 source for the New York case, PDA conducted an environmental investigation at dairy A in December 2018. PDA collected individual milk samples from all cows, excluding those known not to have been vaccinated against B. abortus, and from the bulk milk tank, which included milk pooled from all cows. All milk samples underwent polymerase chain reaction (PCR) testing and culture; whole-genome sequencing (WGS) was performed on patient and milk sample isolates. PDA conducted a traceback investigation of any cow with a milk sample that tested positive for RB51. PADOH worked with the raw milk cooperative that distributed dairy A’s milk to notify potentially exposed consumers and distributed notifications through Epi-X^§ to identify cases.

Dairy A sold only raw milk and did not provide RB51 vaccination to cows born there (16 of the 30-cow herd). The remaining 14 cows were born outside the dairy and had inadequate vaccination records to determine whether they had received RB51. Because these cows might have been vaccinated, milk samples were collected from them. RB51 was detected by PCR and isolated in milk samples collected from the bulk tank and a single cow (cow 122). WGS identified two distinct RB51 strains shed by cow 122: one matched the 2018 New York patient’s isolate (3 single nucleotide polymorphisms [SNPs] different) and one, unexpectedly, matched the 2017 New Jersey patient’s isolate (1 SNP different). The two different RB51 strains were also shed from different quarters of cow 122’s udder.

Traceback revealed that cow 122 had received RB51 in 2011 and was purchased by dairy A in 2016. During 2016–2018, dairy A distributed raw milk potentially contaminated with RB51 to 19 states; PADOH notified those states’ public health veterinarians. PADOH provided a letter with RB51 information and brucellosis prophylaxis recommendations to the cooperative, which they distributed to dairy A customers. No additional cases were identified. Cow 122 was excluded from milk production, and serial PCR testing of bulk milk samples were subsequently negative for RB51.

Isolation of two different RB51 strains from different quarters of a cow’s udder has not previously been reported. These infections highlight the need to prevent RB51 infections. Raw milk consumption is also associated with serious illnesses caused by other pathogens, including Campylobacter spp., Shiga toxin–producing Escherichia coli, and Salmonella spp. (4). During 2007–2012, the number of raw milk outbreaks in the United States increased; 66 (81%) of 81 reported outbreaks occurred in states where raw milk sale is legal (5). Pregnant women, children, older adults, and persons with immunocompromising conditions are at greatest risk for infection.^¶

To eliminate infection risk from milkborne pathogens, including RB51, all milk should be pasteurized. Because limited information is available about intermittent or continuous RB51 shedding among dairy cows, more research is needed to more fully understand this emerging public health threat for milk consumers. States can also consider the United States Animal Health Associations’ recommendations regarding the need for RB51 vaccination in areas where B. abortus is not endemic in wildlife.

Notes from the field: Brucella abortus RB51 infections associated with consumption of raw milk from Pennsylvania—2017 and 2018, 17 April 2020

Morbidity and Mortality Weekly Report

Joann F. Gruber, PhD^1,2; Alexandra Newman, DVM³; Christina Egan, PhD³; Colin Campbell, DVM⁴; Kristin Garafalo, MPH⁴; David R. Wolfgang, VMD⁵; Andre Weltman, MD²; Kelly E. Kline, MPH²; Sharon M. Watkins, PhD²; Suelee Robbe-Austerman, DVM, PhD⁶; Christine Quance⁶; Tyler Thacker, PhD⁶; Grishma Kharod, MPH¹; Maria E. Negron, DVM, PhD¹; Betsy Schroeder, DVM²

https://www.cdc.gov/mmwr/volumes/69/wr/mm6915a4.htm

More Tragically Hip, with fellow Kingston, Ontario (that’s in Canada) native Dan Aykroyd blowing the harp.

Crypto in raw milk

Posted on April 22, 2020 by Douglas Powell

This review analysed outbreaks of human cryptosporidiosis due to raw milk. The objective of our study was to highlight and identify underestimated and underreported aspects of transmission of the parasite as well as the added value of genotyping Cryptosporidium isolates.

Methods

We conducted a descriptive literature review using the digital archives Pubmed and Embase. All original papers and case reports referring to outbreaks of Cryptosporidium due to unpasteurized milk were reviewed. The cross-references from these publications were also included.

Results

Outbreaks have been described in the USA, Australia, and the UK. Laboratory evidence of Cryptosporidium from milk specimens was lacking in the majority of the investigations. However, in most recent reports molecular tests on stool specimens along with epidemiological data supported that the infection was acquired through the consumption of unpasteurized milk. As the incubation period for Cryptosporidium is relatively long (days to weeks) compared with many other foodborne pathogens (hours to days), these reports often lack microbiological confirmation because, by the time the outbreak was identified, the possibly contaminated milk was not available anymore.

Conclusion

Cryptosporidiosis is generally considered a waterborne intestinal infection, but several reports on foodborne transmission (including through raw milk) have been reported in the literature. Calves are frequently infected with Cryptosporidium spp., which does not multiply in milk. However, Cryptosporidium oocysts can survive if pasteurization fails. Thus, pasteurization is essential to inactivate oocysts. Although cryptosporidiosis cases acquired from raw milk are seldom reported, the risk should not be underestimated and Cryptosporidium should be considered as a potential agent of contamination. Genotyping Cryptosporidium isolates might be a supportive tool to strengthen epidemiologic evidence as well as to estimate the burden of the disease.

A review of outbreaks of cryptosporidiosis due to unpasteurized milk, 15 April 2020

Infection

Tamara Ursini, Lucia Moro, Ana Requena-Méndez, Giulia Bertoli & Dora Buonfrate

https://link.springer.com/article/10.1007/s15010-020-01426-3

Brucellosis linked with raw milk

Posted on April 22, 2020 by Douglas Powell

In July 2017, Texas health officials documented the first human case of domestically acquired RB51 infection associated with raw milk consumption from a Texas dairy (3). In October 2017, a second RB51 case associated with raw milk consumption was documented in New Jersey^†; the milk source was not identified at the time.

Notes from the field: Brucella abortus RB51 infections associated with consumption of raw milk from Pennsylvania—2017 and 2018, 17 April 2020

Morbidity and Mortality Weekly Report pp.482-483

https://www.cdc.gov/mmwr/volumes/69/wr/mm6915a4.htm

Vibrio and oysters: A review

Posted on April 21, 2020 by Douglas Powell

Vibrio parahaemolyticus is a Gram‐negative bacterium that is naturally present in the marine environment. Oysters, which are water filter feeders, may accumulate this pathogen in their soft tissues, thus increasing the risk of V. parahaemolyticus infection among people who consume oysters. In this review, factors affecting V. parahaemolyticus accumulation in oysters, the route of the pathogen from primary production to consumption, and the potential effects of climate change were discussed. In addition, intervention strategies for reducing accumulation of V. parahaemolyticus in oysters were presented.

A literature review revealed the following information relevant to the present study: (a) managing the safety of oysters (for human consumption) from primary production to consumption remains a challenge, (b) there are multiple factors that influence the concentration of V. parahaemolyticus in oysters from primary production to consumption, (c) climate change could possibly affect the safety of oysters, both directly and indirectly, placing public health at risk, (d) many intervention strategies have been developed to control and/or reduce the concentration of V. parahaemolyticus in oysters to acceptable levels, but most of them are mainly focused on the downstream steps of the oyster supply chain, and (c) although available regulation and/or guidelines governing the safety of oyster consumption are mostly available in developed countries, limited food safety information is available in developing countries. The information provided in this review may serve as an early warning for managing the future effects of climate change on the safety of oyster consumption.

Managing the risk of vibrio parahaemolyticus infections associated with oyster consumption: A review

Comprehensive Reviews in Food Science and Food Safety

Nodali Ndraha, Hin‐chung Wong, Hsin‐I Hsiao

https://doi.org/10.1111/1541-4337.12557

https://onlinelibrary.wiley.com/doi/full/10.1111/1541-4337.12557

C. diff rates decline

Posted on April 12, 2020 by Douglas Powell

Efforts to prevent Clostridioides difficile infection continue to expand across the health care spectrum in the United States. Whether these efforts are reducing the national burden of C. difficile infection is unclear.

The Emerging Infections Program identified cases of C. difficile infection (stool specimens positive for C. difficile in a person ≥1 year of age with no positive test in the previous 8 weeks) in 10 U.S. sites. We used case and census sampling weights to estimate the national burden of C. difficile infection, first recurrences, hospitalizations, and in-hospital deaths from 2011 through 2017. Health care–associated infections were defined as those with onset in a health care facility or associated with recent admission to a health care facility; all others were classified as community-associated infections. For trend analyses, we used weighted random-intercept models with negative binomial distribution and logistic-regression models to adjust for the higher sensitivity of nucleic acid amplification tests (NAATs) as compared with other test types.

RESULTS

The number of cases of C. difficile infection in the 10 U.S. sites was 15,461 in 2011 (10,177 health care–associated and 5284 community-associated cases) and 15,512 in 2017 (7973 health care–associated and 7539 community-associated cases). The estimated national burden of C. difficile infection was 476,400 cases (95% confidence interval [CI], 419,900 to 532,900) in 2011 and 462,100 cases (95% CI, 428,600 to 495,600) in 2017. With accounting for NAAT use, the adjusted estimate of the total burden of C. difficile infection decreased by 24% (95% CI, 6 to 36) from 2011 through 2017; the adjusted estimate of the national burden of health care–associated C. difficileinfection decreased by 36% (95% CI, 24 to 54), whereas the adjusted estimate of the national burden of community-associated C. difficile infection was unchanged. The adjusted estimate of the burden of hospitalizations for C. difficile infection decreased by 24% (95% CI, 0 to 48), whereas the adjusted estimates of the burden of first recurrences and in-hospital deaths did not change significantly.

CONCLUSIONS

The estimated national burden of C. difficile infection and associated hospitalizations decreased from 2011 through 2017, owing to a decline in health care–associated infections. (Funded by the Centers for Disease Control and Prevention.)

Trends in US burden of clostridioides difficile infection and outcomes, 02 April 2020

New England Journal of Medicine

Alice Y. Guh, M.D., M.P.H., Yi Mu, Ph.D., Lisa G. Winston, M.D., Helen Johnston, M.P.H., Danyel Olson, M.S., M.P.H., Monica M. Farley, M.D., Lucy E. Wilson, M.D., Stacy M. Holzbauer, D.V.M., M.P.H., Erin C. Phipps, D.V.M., M.P.H., Ghinwa K. Dumyati, M.D., Zintars G. Beldavs, M.S., Marion A. Kainer, M.B., B.S., M.P.H., Maria Karlsson, Ph.D., Dale N. Gerding, M.D., and L. Clifford McDonald, M.D.

DOI: 10.1056/NEJMoa1910215

https://www.nejm.org/doi/10.1056/NEJMoa1910215

barfblog

safe food from farm to fork

Category Archives: Other Microorganisms