Listeria

See also: Study at London

• Es anaeróbica facultativa.
• Bacilo Gram positivo, pequeño, alargado y  que no forma esporas,
• Tolerante a sales,  criotolerante y su vez ácido- tolerante, entre otras características. 
• Posee una gran  resistencia a factores ambientales lo cual le permite estar ampliamente distribuida en la naturaleza,
• Se puede aislarse en suelo, agua, vegetación, animales 
  principalmente ganado bovino, porcino y ovino) además de aves silvestres, c
  rustáceos e insectos y se puede ser encontrada  frecuentemente en alimentos.
•  Crece en un amplio rango de temperaturas (de -7 °C a 45 °C).Así pues, carne, productos lácteos y productos frescos pueden ser contaminados por este patógeno.
• Puede originar bajo ciertas condiciones la enfermedad denominada Listeriosis. Brotes de listeriosis aparecen a partir de fuentes comunes tales como alimentos procesados listos para consumir, conservados durante largo tiempo en los refrigeradores.

On October 19, 2011, FDA released a document1 which provides an overview of factors that potentially contributed to the contamination of fresh, whole cantaloupe with the pathogen Listeria monocytogenes which was implicated in a multi-state outbreak of listeriosis. In early September 2011, the Food and Drug Administration (FDA), in conjunction with the Centers for Disease Control and Prevention (CDC) and state health departments, began to investigate a multi-state outbreak of listeriosis. Early in the investigation, cantaloupes from Jensen Farms in the southeast region of Colorado were implicated in the outbreak.


On September 10, 2011, FDA, along with Colorado state officials, conducted an inspection at Jensen Farms and collected multiple samples, including whole cantaloupes and environmental (non-product) samples from within the facility, for laboratory analysis to identify the presence of Listeria monocytogenes. Of the 39 environmental swabs collected from within the facility, 13 were confirmed positive for Listeria monocytogenes with pulsed-field gel electrophoresis (PFGE) pattern combinations that were indistinguishable from three of the four outbreak strains collected from affected patients. Of the 13 positive environmental swabs, 12 were collected at the processing line and 1 was collected from the packing area. Cantaloupe collected from the firm’s cold storage during the inspection was also confirmed positive for Listeria monocytogenes with PFGE pattern combinations that were indistinguishable from two of the four outbreak strains.


FDA Environmental Swabs Positive Results


Processing Line


9 positive samples from the grading belt


Swabs 21, 22, 23, 24, 26, 27, 29, 30 & 33
2 positive samples from the conveyor


Swabs 20 & 28


1 positive sample from the felt rollers


Swab 13
Packing Area


1 positive sample from the conveyor belt


Swab 34


FDA Product Sample Results


1 Cantaloupe Sample collected from cold storage


5 subs tested positive


(10 whole cantaloupes or “Subs”)


Please refer to the section below for


FDA’s Sample Records and Results on Jensen Farms


As a result of the isolation of outbreak strains of Listeria monocytogenes in the environment of the packing facility and whole cantaloupes collected from cold storage, and the fact that this is the first documented listeriosis outbreak associated with fresh, whole cantaloupe in the United States, FDA initiated an environmental assessment in conjunction with Colorado state and local officials. FDA, state, and local officials conducted the environmental assessment at Jensen Farms on September 22-23, 2011. The environmental assessment was conducted to gather more information to assist FDA in identifying the factors that potentially contributed to the introduction, growth, or spread of the Listeria monocytogenes strains that contaminated the cantaloupe.


FDA identified the following factors as those that most likely contributed to the introduction, spread, and growth of Listeria monocytogenes in the cantaloupes:


Introduction:


There could have been low level sporadic Listeria monocytogenes in the field where the cantaloupe were grown, which could have been introduced into the packing facility.

A truck used to haul culled cantaloupe to a cattle operation was parked adjacent to the packing facility and could have introduced contamination into the facility.

Spread:
The packing facility’s design allowed water to pool on the floor near equipment and employee walkways.


The packing facility floor was constructed in a manner that made it difficult to clean the packing equipment was not easily cleaned and sanitized; washing and drying equipment used for cantaloupe packing was previously used for postharvest handling of another raw agricultural commodity


Growth:
There was no pre-cooling step to remove field heat from the cantaloupes before cold storage. As the cantaloupes cooled there may have been condensation that promoted the growth of Listeria monocytogenes


FDA’s findings regarding this particular outbreak highlight the importance for firms to employ good agricultural and management practices in their packing facilities as well as in growing fields. FDA recommends that firms employ good agricultural and management practices recommended for the growing, harvesting, washing, sorting, packing, storage and transporting of fruits and vegetables sold to consumers in an unprocessed or minimally processed raw form.


FDA has issued a warning letter2 to Jensen Farms based on environmental and cantaloupe samples collected during the inspection. FDA’s investigation at Jensen Farms is still considered an open investigation.

About 18% of the fish sampled didn't match the names on placards, labels and menus, according to a study by 'Consumer Reports'.

About 18% of the fish sampled didn't match the names on placards, labels and menus, according to a study by 'Consumer Reports'.


Consumer Reports Friday will reveal a mislabeled seafood scam that leaves millions of consumers clueless whether the fish they think they're buying is the fish they're actually getting.


The world's largest independent product-testing organization Friday will reveal that 22% of the seafood it tested at supermarkets, restaurants, fish markets, gourmet stores and big-box stores in three states was either mislabeled, incompletely labeled or misidentified by store or restaurant employees.


"Consumers are getting ripped off when they buy fish," says Kim Kleman, editor-in-chief of Consumer Reports.


This is no small matter. Americans spent $80.2 billion on seafood last year, up $5 billion from 2009. Mislabeling can be a serious health issue. Some consumers have allergies to specific types of fish, and pregnant women can end up eating fish they shouldn't — with high concentrations of mercury. Others trying to purchase more sustainable fish are being sold cheaper, unsustainable species.


The investigation, which took place in New York, New Jersey and Connecticut, included 190 pieces of fresh and frozen seafood that were DNA tested by two outside labs. The findings, in the December issue of Consumer Reports, do not speculate about the reasons for the fraud. Some mislabeling snafus:


•Only four of the 14 different types of fish purchased — Chilean sea bass, coho salmon and bluefin and ahi tuna — were always identified correctly.


•Not one of the 10 lemon soles tested was lemon sole — but more common and cheaper flounder. And of 22 red snapper samples, not one was definitively red snapper, though eight couldn't be ruled out.

•Some 18% of the samples didn't match the names on placards, labels or menus. Another 4% were incompletely labeled or misidentified.


Consumers Union, the public policy division of Consumer Reports, is calling for legislation and standardized seafood labeling.


Officials at the Food and Drug Administration, which oversees food labeling, say they're aware of the problem. "It's illegal to mislabel food," spokesman Doug Karas says. The agency recently supplied six labs with DNA-testing equipment for testing to begin in 2012, he says. But, he adds, "Primarily we look at food safety," not fraud.


But, Kleman says, "I don't think we should have to choose between safety and fraud."

Dear Dr. Donohue • Recently I heard that a number of people died from eating cantaloupe that had a bacterium called listeria. What causes it, and how did it originate? I have been growing vegetables all my life and never heard of it. Does it live just on the outside of fruits and vegetables, or does it get inside? Are there signs that listeria is on the ground or on foods? Does cooking kill it? — W.H.
Answer • Listeria is not a new bacterium. It's been around on this planet a lot longer than any of us current humans have been. It's found in soil, decaying vegetation, rivers, streams, lakes and in the digestive tracts of many animals and their feces. Many of us have been infected with it, but most often symptoms are so mild that they go unreported and untreated. Only on a relatively few occasions has listeria been a threat to life and health. The recent cantaloupe episode was one of those occasions.
This bacterium does not penetrate into the interior of fruits or vegetables. It's on the cantaloupe rind. Cutting the fruit with a knife permits bacteria to cling to the knife and be deposited inside the melon, on the edible part. All fruits and vegetables should be washed thoroughly before they're eaten.
Meats, chicken and seafood also can harbor listeria. They should all be well-cooked; cooking kills the germ. Unpasteurized milk is another food capable of transmitting it. It is not transferred from one human to another. An infected mother can pass the germ to her fetus.
People who are quite susceptible to infection with listeria are ones whose immune system is not as robust as it should be. Older individuals and newborns are at greater risk of becoming infected than are others. For people with healthy immune systems, the chief signs of infection are nausea, vomiting and diarrhea. Many never develop any signs. Heavy infections with great numbers of listeria cause a much more severe illness and can be fatal. Those examples actually are quite rare in comparison to the total number of infections.
You cannot tell if a food or if soil has listeria by sight alone.
Dear Dr. Donohue • On TV, I heard a doctor sing the importance of vitamin A. He also cautioned about the overuse of vitamin supplements. I don't know how valid studies on vitamins are, but they eventually become obsolete with the newest research. I will be 91 in a few months. — R.D.
Answer • I always pay attention to what 90-year-olds say. They must've done things right, or they wouldn't be here. I agree with you. Nutritional advice changes so rapidly and so radically that it is hard to evaluate it. I guess we have to judge what makes the best sense.

Lister moved from Scotland to King's College Hospital, in London, and became the second man in England to operate on a brain tumor. He also developed a method of repairing kneecaps with metal wire and improved the technique of mastectomy.

His discoveries were greatly praised and in 1883 he was created a Baronet, of Park Crescent in the Parish of St Marylebone in the County of Middlesex.^[8] In 1897 he was further honoured when he was raised to the peerage as Baron Lister, of Lyme Regis in the County of Dorset.

He also became one of the twelve original members of the Order of Merit and a Privy Councillor in the Coronation Honours in 1902.
Among his students at King's College London was Robert Hamilton Russell, who later moved to Australia.