Welcome to the Microbiology Information

Listeria appears again – but this time in sandwiches wwhere it was sold to 20 people at Middlemore Hospital in New Zealand.

These pre-packaged Thai chicken sandwiches were sold on Monday at the hospital’s Aviary Cafe, which is mainly used by staff.

The contamination was detected in routine listeria testing where the results were given to the hospital yesterday.

It was not known last night whether other sandwich varieties at the cafe were infected, or if other products from the sandwiches’ supplier, Naturezone, were infected with listeria and had been distributed to other outlets.

The bacterium can be fatal to people with low immune systems and can cause miscarriages or stillbirths if it infects pregnant women.

A spokeswoman for Spotless Services, the company that runs the cafe, said it was not yet known how many of its outlets had been stocked with the sandwiches. Naturezone could not be reached for comment last night.

Auckland Regional Public Health Service spokesman Dr Greg Simmons said last night that greatly improved methods of testing were bringing the listeria cases to the surface.

All positive tests in the past three weeks had come from the same testing facility.

“We are conducting a thorough site inspection at the company and we will ensure extensive product and environmental testing to identify the source,” Dr Simmons said

Despite the relatively low risk, he said, it was a serious situation.

“We are concerned that a whole lot of ready-to-eat products look like they are being contaminated. We would be silly not to be concerned.”

The bacterium usually produces fever, diarrhoea and general unwellness within three weeks of infection, although it can take as long as 10 weeks for symptoms to show.

Here is the draft policy (Sec. 555.320) for Listeria monocytogenes in Ready To Eat (RTE) Foods.

This draft guideline, when finalized, will represent the Food and Drug Administration’s (FDA’s) current thinking on this topic. It does not create or confer any rights for or on any person and does not operate to bind FDA or the public. You can use an alternative approach if the approach satisfies the requirements of the applicable statutes and regulations. If you want to discuss an alternative approach, contact the FDA staff responsible for implementing this guidance. If you cannot identify the appropriate FDA staff, call the appropriate telephone number listed on the title page of this guidance.

INTRODUCTION:
The purpose of this Compliance Policy Guide is to provide guidance to FDA Staff on FDA’s enforcement policy for Listeria monocytogenes (L. monocytogenes) in foods.

FDA’s guidance documents, including this guidance, do not establish legally enforceable responsibilities. Instead, guidances describe the Agency’s current thinking on a topic and should be viewed only as recommendations, unless specific regulatory or statutory requirements are cited. The use of the word should in Agency guidances means that something is suggested or recommended, but not required.

BACKGROUND:
L. monocytogenes is a pathogenic bacterium that is widespread in the environment and may be introduced into a food processing facility. L. monocytogenes can contaminate foods and cause a mild illness (called listerial gastroenteritis) or a severe, sometimes life-threatening, illness (called invasive listeriosis). Foods that have been implicated in outbreaks of invasive listeriosis have been foods that are ready-to-eat (RTE).

RTE foods can be contaminated if ingredients in the foods are contaminated with L. monocytogenes and are not treated to destroy viable cells of this pathogen, or if L. monocytogenes is allowed to contaminate the RTE food because of improper sanitary conditions or practices. Most RTE foods do not contain detectable numbers of L. monocytogenes. For many RTE foods, contamination with L. monocytogenes can be avoided – e.g., through the application of current good manufacturing practice requirements that establish controls on ingredients, listericidal processes, segregation of foods that have been cooked from those that have not, and sanitation. Sanitation controls include effective environmental monitoring programs designed to identify and eliminate L. monocytogenes in and on surfaces and areas in the plant.

In 2003, FDA and the Food Safety and Inspection Service of the United States Department of Agriculture, in consultation with the Centers for Disease Control and Prevention of the United States Department of Health and Human Services, released a quantitative assessment (the Risk Assessment) of relative risk associated with consumption of certain categories of RTE foods that had a history of contamination with L. monocytogenes, or that were implicated epidemiologically with an outbreak or a sporadic case of listeriosis. The Risk Assessment estimated that the risk of listeriosis would vary widely among these food categories.

According to the Risk Assessment, foods estimated to pose the highest risk of being associated with listeriosis are RTE foods that support the growth of L. monocytogenes. Examples of RTE foods that support the growth of L. monocytogenes include:

Milk;
High fat and other dairy products (e.g., butter and cream);
Soft unripened cheeses (greater than 50 percent moisture) (e.g., cottage cheese and ricotta cheese);
Cooked crustaceans (e.g., shrimp and crab);
Smoked seafood (e.g., smoked finfish and mollusks);
Raw seafood that will be consumed as sushi or sashimi;
Many vegetables (such as broccoli, cabbage, and salad greens);
Non-acidic fruit (such as melon, watermelon, and papaya); and
Some deli-type salads and sandwiches (particularly those containing seafood and those prepared at retail establishments without acidification and/or the addition of antimicrobial substances).

In contrast, the foods estimated to pose the lowest risk of being associated with listeriosis are foods that, because of intrinsic factors, extrinsic factors, and/or processing factors do not support the growth of L. monocytogenes. Intrinsic factors include chemical and physical factors that are normally within the structure of the food, e.g., pH and water activity. Extrinsic factors are those that refer to the environment surrounding the food, e.g., storage temperature. Processing factors include substances added to adjust the pH of food (e.g., acids) and substances that, alone or in combination with other substances, have antimicrobial properties (e.g., sorbates and benzoates). It is well established that L. monocytogenes does not grow when:

The pH of the food is less than or equal to 4.4;
The water activity of the food is less than or equal to 0.92; or
The food is frozen.

Foods may naturally have a pH or water activity that prevents growth of L. monocytogenes or processing factors may be deliberately used to achieve those characteristics (e.g., by adding acid to deli-type salads to bring the pH to less than or equal to 4.4). At pH values above 4.4, processing factors generally are used in combination to prevent the growth of L. monocytogenes (e.g., sorbates or benzoates may be used in combination with organic acids such as acetic acid, lactic acid, and citric acid in foods such as deli-type salads). The effectiveness of a particular listeristatic control measure in preventing growth in a particular RTE food generally is determined case-by-case, for example, using the results of growth studies specific to the food matrix.

Examples of RTE foods that generally are considered to not support the growth of L. monocytogenes include:

Fish that are preserved by techniques such as drying, pickling, and marinating;
Ice cream and other frozen dairy products;
Processed cheese (e.g., cheese foods, spreads, slices);
Cultured milk products (e.g., yogurt, sour cream, buttermilk);
Hard cheeses (less than 39 percent moisture) (e.g., cheddar, colby, and parmesan);
Some deli-type salads, particularly those processed to a pH less than 4.4 and those containing antimicrobial substances such as sorbic acid/sorbates or benzoic acid/benzoates under conditions of use documented to be effective in preventing the growth of L. monocytogenes;
Some vegetables (such as carrots); and
Crackers, dry breakfast cereals, and other dry foods.

Fruits, vegetables, and cheeses (e.g., soft and semi-soft cheeses) not listed in this CPG may include some products that support growth as well as other products that do not support growth.

POLICY:
FDA will review the available evidence on a case-by-case basis to determine if a food is a RTE food that supports growth or a RTE food that does not support growth.

Ready-to-Eat Food

“Ready-to-eat food” (RTE food) means a food that is customarily consumed without cooking by the consumer, or that reasonably appears to be suitable for consumption without cooking by the consumer.

A food may be considered to be suitable for consumption without cooking by the consumer, and thus a RTE food, even though cooking instructions are provided on the label. For examples, fresh and frozen crabmeat and individually quick frozen (IQF) peas and corn may be RTE foods. Some consumers eat such products without cooking, because they appear to be ready-to-eat.

Ready-to-Eat Foods that Support Growth of L. monocytogenes

Generally, we intend to consider that a RTE food will support the growth of L. monocytogenes if it does not meet the characteristics of a RTE food that does not support growth, as indicated in section III.C.

FDA may regard a RTE food that supports growth of L. monocytogenes to be adulterated within the meaning of section 402(a)(1) of the Federal Food, Drug, and Cosmetic Act (the Act; the FD&C Act) (21 U.S.C. 342(a)(1)) when L. monocytogenes is present in the food based on the detection method indicated in section IV.A.

Ready-to-Eat Foods that Do Not Support Growth of L. monocytogenes

A RTE food does not support the growth of L. monocytogenes if the food:
Has a pH that is less than or equal to 4.4; or
Is customarily held and consumed in a frozen state; or
Has a water activity that is less than 0.92; or
Is processed using an effective listeristatic control measure (e.g., an antimicrobial substance or a combination of factors such as pH, water activity, and antimicrobial substances).

FDA may regard a RTE food that does not support the growth of L. monocytogenes to be adulterated within the meaning of section 402(a)(1) of the Act (21 U.S.C. 342(a)(1)) when L. monocytogenes is present at or above 100 colony forming units per gram of food (cfu/g)

REGULATORY ACTION GUIDANCE:
Ready-to-Eat Foods that Support Growth of L. monocytogenes

The following represents criteria for recommending legal action to CFSAN/Office of Compliance/Division of Enforcement (HFS-605):
L. monocytogenes is detected in one or more subsamples of a RTE food that supports the growth of L. monocytogenes.

Use Bacteriological Analytical Manual Online, Chapter 10 – “Listeria monocytogenes,” “Detection and Enumeration of Listeria monocytogenes in Foods” as the method for detecting and confirming presence of L. monocytogenes (available at http://www.cfsan.fda.gov/~ebam/bam-10.html).

Ready-to-Eat Foods that Do Not Support Growth of L. monocytogenes

Consult with CFSAN/Office of Compliance/Division of Enforcement (HFS-605) before recommending legal action for RTE foods that do not support the growth of L. monocytogenes. Use ISO 11290-2:1998(E) “Microbiology of food and animal feeding stuffs – Horizontal method for the detection and enumeration of Listeria monocytogenes – Part 2: Enumeration method” as the method for enumerating L. monocytogenes. (ISO 11290-2:1998/Amd. 1:2004(E) “Microbiology of food and animal feeding stuffs – Horizontal method for the detection and enumeration of Listeria monocytogenes – Part 2: Enumeration method AMENDMENT 1: Modification of the enumeration medium” amends ISO 11290-2:1998(E). The amendment uses ALOA agar instead of PALCAM agar. If ALOA agar is not commercially available in the United States, use PALCAM according to ISO 11290-2:1998(E)). ISO methods are available from the International Organization for Standardization at http://www.iso.org/iso/en/ISOOnline.frontpage.

Use rapid biochemical test kits according to the Bacteriological Analytical Manual Online, Chapter 10 – “Detection and Enumeration of Listeria monocytogenes in Foods” Section E-11 (available at http://www.cfsan.fda.gov/~ebam/bam-10.html), instead of ISO 11290-2:1998(E) Section 9.5, for confirmation of L. monocytogenes isolates.

Foods that are Not RTE Foods
Consult with CFSAN/Office of Compliance/Division of Enforcement (HFS-605) when L. monocytogenes is present in a food that is not a RTE food.

Other Considerations

The criteria in this guidance do not establish an acceptable level of L. monocytogenes in food. FDA may choose to take legal action against adulterated food that does not meet the criteria for recommending legal action to CFSAN.

Further, the criteria in this guidance do not excuse violations of the requirement in section 402(a)(4) of the Act (21 U.S.C. 342(a)(4)) that food may not be prepared, packed, or held under insanitary conditions or the requirements in FDA’s good manufacturing practices regulation (21 CFR part 110). As set out in 21 CFR 110.80, food manufacturers must take “[a]ll reasonable precautions … to ensure that production procedures do not contribute contamination from any source.”

SPECIMEN CHARGES:
Domestic Seizure

The article of food was adulterated when introduced into and while in interstate commerce and is adulterated while held for sale after shipment in interstate commerce within the meaning of the Act, 21 U.S.C. 342(a)(1), in that it bears and contains a poisonous or deleterious substance, namely Listeria monocytogenes, which may render it injurious to health.

Import Detention
The article of food is subject to refusal of admission pursuant to section 801(a)(3) of the FD&C Act in that it appears to be adulterated within the meaning of section 402(a)(1) of the FD&C Act in that it bears and contains a poisonous or deleterious substance, Listeria monocytogenes, which may render it injurious to health.

Public health officials in the U.S. are investigating a major outbreak of listeria and have found up to 16 samples with the listeria bacteria at a milk processing plant.

The outbreak has resulted in the deaths of 3 elderly men who have died since June after drinking pasteurized milk that was contaminated with the bacteria.

The same strain of listeria also sickened a pregnant woman, who then miscarried and a second woman also was sickened after drinking milk from the plant.

The dairy processing plant in Shrewsbury is 35 miles west of Boston in Massachusetts, and is owned by Whittier Farms.

While officials have yet to determine exactly how the milk was contaminated, one environmental swab, one skim milk sample and seven flavored milk samples tested positive for the same strain of listeria that is now being blamed for the outbreak that sickened people.

The milk appears to have been contaminated during the production process and could have been lurking somewhere within the machinery. Experienced microbiologists are currently on site to determine the cause of the outbreak and to find potential reservoirs of the deadly micro-organisms.

So far, no further cases have been reported and health officials maintain that the health risk to the public is low.

The processing plant distributes milk under various brand names to stores across central Massachusetts and also operates a 500-acre farm in the town of Sutton.

Officials say the plant has been closed since December and will remain so while investigations continue and the bacterium is completely eradicated.

Here’s what they say on their site:

“Whittier Farms Inc. was notified today by the Department of Public Health that a press release would be issued today informing the public that Whittier Farms Inc. is being linked to cases involving listeria. Whittier Farms is fully cooperating with this investigation and will continue to do so.”

Listeriosis is a type of food poisoning that can be particularly dangerous to the elderly, infants, pregnant women and people with low immune system such as those chronic medical conditions; the symptoms include fever, abdominal cramps, headache, stiffness, nausea and diarrhea.

An eight hour listeria test is what DuPont Qualicon has just annouced.

The new test is genetic-based and allows food companies to detect Listeria on environmental surfaces in only eight hours.

A spokes person for DuPont Qualicon says the new assay “is the first commercial application of Reverse-Transcriptase PCR for bacterial testing in food.” It is part of a suite of BAX(R) system products.

“This flexible test can give food companies clear, precise results at the end of a shift,” said Kevin Huttman, president of DuPont Qualicon. “With fast, accurate detection of Listeria, even at low concentrations, food processors get the information they need to take action sooner and release product faster.”

Listeria is found in many kinds of foods and us usually killed with proper cooking. Ready-to-eat products, such as hot dogs and deli meat, can become contaminated between cooking and packaging, however. The infection Listeriosis is caused by eating food contaminated with pathogenic Listeria monocytogenes. This illness is especially risky for pregnant women and immuno-compromised individuals. DuPont Qualicon said.

Applications

The BAX® system detects all species of Listeria, even at very low concentrations (101 cfu/mL).

With reverse-transcriptase PCR, samples do not require the usual 24-48 hour enrichment in nutrient brotoh. Instead, Listeria cells are resuscitated by heating in the collection buffer solution for four hours, providing a jump-start to the process.

Validation studies on stainless steel using both the classic and Q7 models have shown that the BAX® system detected more positive results on spiked samples than the reference USDA FSIS culture method. In a panel of 58 strains across 7 species of Listeria and 52 strains of non-Listeria, the assay demonstrated 100% inclusivity/exclusivity.

Approvals

The BAX® system 8-hour Listeria assay will be submitted to AOAC-RI for Performance Tested Method approval.

Source

The EU and US positions at a Codex meeting to set international standards on food safety foreshadow future legislation that would affect hygiene control measures in manufacturing plants, and the manufacture of powdered formulae, ready-to-eat foods, and pasteurised liquid eggs.

In the six day meeting which ended on the 4 November in New Delhi, India, national representatives to Codex’s food hygiene committee also decided to start work on drafting safety guidelines setting standards to control Campylobacter and Salmonella specie in broiler chicken meat.

At the New Delhi meeting they discussed various positions, including those relating to proposed standards for pasteurized liquid whole eggs, hygienic practice for processing powdered formulae for infants and children, pathogen control measures for Listeria monocytogenes in ready-to-eat foods & guidelines for evaluating manufacturing control measures.

Codex is a multilateral body set up to develop food safety and other standards that would apply to all member countries.

It operates under the aegis of the UN’s Food and Agriculture Organisation and the World Health Organisation.

The standards are recognised as international benchmarks by one of the multilateral agreements of the World Trade Organisation (WTO) and aim to eliminate many of what the UN calls “unjustified technical barriers” to food imports set up by some countries.

The standards also serve to harmonise food safety laws globally, aiding multinational processors in following the law no matter where they trade.

The standards on each particular topic and food type can undergo a huge revision process at various levels of Codex decision making bodies, over a number of years. Member countries must then transcribe the standards into their national laws.

The proposed standard setting what pathogen controls for Listeria monocytogenes ready-to-eat food processors must put in place is based in the main on US risk assessments, according to Codex documents.

Based on the risk assessments, a working group led by Germany concluded that a zero tolerance standard for L. monocytogenes have a proportional reduction in the rates of illness from foods contaminated with the pathogen.

A study commissioned by the food hygiene committee showed that the application of microbiological criteria at a given point of the production chain is only one of the measures that need to be applied, to bring down contamination rates.

The committee proposes to exclude from the criteria foods that are processing in such a way to ensure the killing of L. monocytogenes and for which recontamination is not possible.

The foods must also be processed and handled under systems adhering to good hygienic practice (GHP), a separate international standard.

Such foods include those given a listericidal treatment in the package and those that are produced through aseptic processing and packaging.

The group includes dehydrated products such as powdered milk, dehydrated soup mixes, herbs and spices, fresh, uncut and unprocessed vegetables and fruits, soft drinks, beer and spirits.

At the meeting the EU delegation also proposed that the standard should specifically include ready-to-eat foods for infants and those with medical conditions.

The EU supports a 100 colony forming units per gram (cfu/g) limit on the pathogen for ready-to-eat foods, if the food manufacturer is able to demonstrate the maximum would not be exceeded throughout the shelf-life.

The EU delegation also noted that setting a zero tolerance standard, where a negative reading is set at 25g = 0.04 colony forming units per gram (cfu/g) “might cause misunderstandings”.

The EU also wants clarification on foods not covered by the testing standard, pointing out that previous discussions had also discussed products for which Listeria monocytogenes is “very unlikely” to be detected.

Clarification is also needed about the proposed exclusion of foods for which there is less than ’1 log’ growth during 1.3 times the expected shelf life, the EU stated in its submission. Various definitions of ‘shelf-life’ might confuse the issue.

At the meeting the Codex committee also set its priorities for proposed standards, with those for egg products topping the list.

Other priorities in order are standards for infant and children foods; combining two codes of practice for various nuts into one; setting a single hygienic code for fruits, vegetable and products made from them; quick frozen foods, spices and aromatic plants; low-acid and acidified low-acid canned foods and aseptically processed and packaged low-acid canned foods, natural mineral waters, frog legs, catering, and street-vended foods.

The WTO’s Codex Alimentarius Commission is the body set up to harmonise food safety and other export requirements around the world.

Member countries’ representatives meet regularly to debate a common position or standard on every aspect of such requirements, from the holding temperatures in frozen meat should be kept at, to processing requirements for specific types of cheeses.

Agreements forged at Codex meetings could eventually affect the way processors operate worldwide as they become incorporated into national laws in various countries around the world.

Source

According to Itar-Tass (Moscow), a total of 444 construction workers has been infected with food poisoning and remains in hospitals within the Moscow region.

A total of 444 workers employed at Sheremetyevo (3 terminal in Moscow), the IKEA – Khimki Business Park construction sites had been hospitalized since June 20 with symptoms of food poisoning, a representative of the Ministry for Emergency Situations said.

The workers – citizens of Russia, the CIS and Turkey, lived at the Iskorka and Morozovka recreation compounds in the village of Myshetskoye of the Solnechnogorsk district. Poor quality food was is a presumed cause of food poisoning, a source of the infection is being established, the same source said.

Managers of the ENKA Company have been questioned within the framework of an investigation into mass food poisoning of construction workers employed at Terminal 3 at Sheremetyevo airport.

Almost all of the workers arrived in Russia from Turkey, Tajikistan, Uzbekistan, and Kyrgyzstan to work on construction sites in Moscow. They lived on the premises of Ozero Krugloye recreation center in the Solnechnogorsk district.

According to preliminary data, all the victims have been infected with the salmonella bacteria and the source of the food for the workers were brought from Moscow.

The ENKA company might be stripped of the right to employ foreign workforce, the regional branch of the Federal Migration Service told Tass. “Since the company failed to fulfill its guarantees to the workers, which entailed grave consequences – mass food poisoning, and failed to ensure proper living conditions for the workers we are raising the issue of recalling the company’s license for the use of foreign workforce,” the Federal Migration Service said.

An operational headquarters for prevention of emergency situations in the Moscow region that is working round the clock has been following the situation. Healthcare Minister of the Moscow region Vladimir Semyonov said the workers’ condition was assessed as “medium seriousness”. Luckily, none of the sick people is in serious condition now, Semyonov said.

Deputy chairman of the government of the Moscow region Sergei Koshman said that the workers lived under conditions that did not meet the norm. Having obtained the license to accommodate 500 people, the employers invited 800 instead, Koshman said.

Source

did you know that red wine is known to have multiple health benefits. Researchers at the University of Missouri-Columbia have found that red wine may also protect humans from common food-borne diseases.

Researchers Azlin Mustapha, associate professor of food science in the College of Agriculture, Food and Natural Resources, and Atreyee Das, a doctoral student in the food science program, are conducting on-going studies examining the inhibitory effects of numerous types of red wines, as well as grape juice, against pathogens and probiotic bacteria, which naturally reside in the intestinal tract and can be beneficial in combating, among other things, high cholesterol and tumors.

They found that red wines – Cabernet, Zinfandel and Merlot in particular – have anti-microbial properties that defend against food-borne pathogens and don’t harm naturally useful bacteria like probiotic bacteria.

E. coli, Salmonella Typhimurium, Listeria monocytogenes and H. pylori were among the pathogens examined. E. coli and Listeria can be fatal. Mustapha said the most promising results involved Helicobacter pylori, which can be transmitted via food and water and is the main cause of stomach ulcers.

“Our study is a little different than those previously reported in the media. Those studies promote moderate red wine consumption for cardiovascular diseases,” she said. “We went a step farther and asked: If red wine is already good for cardiovascular diseases, what about food-borne pathogens? If you get a food-borne illness and drink red wine, will that help decrease the symptoms a little bit? This study showed that the four probiotics tested weren’t inhibited by red wines; the pathogens were.”

In lab tests, Mustapha and Das focused on ethanol, pH levels and reseveratrol, which is a phytochemical found in grape vines and the skin of grapes. It also is responsible for the red coloring in red wines. They found that in addition to ethanol, pH and reseveratrol also may inhibit food-borne pathogens.

Numerous white wines also were tested, but yielded no positive results, the researchers said.

“It’s not just ethanol in the red wine that is inhibitory toward food-borne pathogens, but other factors which include the pH of the wine – because wines are a little acidic, and possibly the phytochemicals may have an effect,” said Mustapha, noting that grape juice produces similar results.

“We hypothesize that these phytochemicals, reseveratrol being the main one, also play a role not just as antioxidants but also may have some inhibitions against food-borne pathogens. Now, we’re concentrating mainly on the reseveratrol effects on these pathogens.”

The findings were recently presented at the Institute of Food Technologists annual conference in Chicago. http://munews.missouri.edu

According to New Scientist, “A comprehensive analysis of both the molecular genetic and phenotypic responses of any organism to the space flight environment has never been accomplished because of significant technological and logistical hurdles.”……until now.

Bacteria flown on the space shuttle mutated in ways that made them nearly three times more deadly to mice, reports a new study. While the bugs are also likely to affect astronauts’ health, the research team found clues that may help render them harmless.

Astrobiologists have long been worried that the low-gravity conditions of space could make disease-causing microbes that hitch-hike on shuttle missions mutate in unpredictable ways. To investigate, Cheryl Nickerson at Arizona State University in Tempe, US, and her colleagues launched flasks of the bacterium Salmonella typhimurium into space on the shuttle Atlantis in September 2006.

The shuttle returned after 12 days, during which time the microbes had altered the way they express 167 genes compared with bacteria that remained on Earth. The team found that these space-mutated bugs were almost three times as likely to kill infected mice compared with their ground-grown counterparts.

That could be bad news if the results hold true for astronauts, since some experiments suggest the weightlessness of space travel suppresses the immune system.

But the news is not all bad. Nickerson and her colleagues also identified the protein, called Hfq, believed to be behind the change. “An overwhelming number of the [affected] genes are regulated by Hfq,” she says.

Archilles’ Heel
Strains of Salmonella without normally functioning Hfq did not show the gene expression changes when they were tested under microgravity conditions in the lab. Nickerson says this knowledge could one day be leveraged to “design targeted strategies and countermeasures to mitigate infectious disease risks to the crew during future missions”.

The work may also help combat Salmonella on Earth. Micro-organisms growing in a liquid in microgravity experience low fluid forces that are similar in many ways to those that the bugs encounter on Earth inside their hosts, she explains. “An exciting part of this work is the opportunity to use spaceflight as a novel research platform for innovations in infectious disease control here on Earth,” she told.

Robert McLean, a microbiologist at Texas State University in San Marcos, US, who has also flown bacterial experiments on space shuttles, is impressed with the new study.

“On Earth, we’re so used to gravity that we ignore it, but for the first time we’re seeing that gravity may be needed for genes to be expressed,” he told New Scientist. “I think that transcends the space programme, and tells us something hugely important about biology in general.”

An unexpected find by a team of University of Georgia scientists suggests that reducing the use of antibiotics on poultry farms will do little, if anything to reduce rates of antibiotic resistant bacteria that have the potential to threaten human health.

Dr. Margie Lee, professor in the UGA College of Veterinary Medicine, and her colleagues have found that chickens raised on antibiotic-free farms and even those raised under pristine laboratory conditions have high levels of bacteria that are resistant to common antibiotics. Her findings, published in the March issue of the journal Applied and Environmental Microbiology, suggest that poultry come to the farm harboring resistant bacteria, possibly acquired as they were developing in their eggs.

“The resistances don’t necessarily come from antibiotic use in the birds that we eat,” Lee said, “so banning antibiotic use on the farm isn’t going to help. You have to put in some work before that.”

Lee and her team sampled droppings from more than 140,000 chickens under four different conditions: 1.) commercial flocks that had been given antibiotics; 2.) commercial flocks that had not been given antibiotics; 3.) flocks raised in a lab that had been given antibiotics; and 4.) flocks raised in a lab that had not been given antibiotics. The researchers examined levels of antibiotic resistance in normal intestinal bacteria that do not cause human illness and – in a companion study published in May in the same journal – also examined levels of drug resistant campylobacter bacteria, a common food-borne cause of diarrhea, cramping and abdominal pain.

They found that even chickens raised in the pristine laboratory conditions had levels of antibiotic resistance levels comparable to what was seen on farms that used antibiotics. Even when the levels were lower, Lee adds, they were still well above the reasonable comfort zone for antibiotic resistance – roughly five to 10 percent.

Seventy-three percent of the bacteria from one flock in the antibiotic-free commercial group were resistant to the drug oxytetracycline, for example, while 90 percent were resistant to the drug in a commercial flock that used antibiotics. Ninety-seven percent were resistant in the experimental flock that was given antibiotics, while forty-seven percent were resistant in the experimental group that was not given antibiotics.

Strikingly, they even found bacteria resistant to streptomycin, a common human antibiotic that is rarely used in poultry and was not used on the farms the researchers studied.

Bacteria swap genes relatively easily, and Lee explained that the concern is that drug resistance genes from bacteria that infect poultry could be passed on to bacteria that cause human illness. With these resistance genes, human bacterial illness could become harder to treat.

These concerns led the European Union to ban the use of antibiotics for growth promotion in chickens in 2006. In 2005, the U.S. Food and Drug Administration banned the use of the drug Baytril (the brand name for enrofloxacin, a fluoroquinolone antibiotic) in poultry, citing concerns that it could lead to resistance in human antibiotics such as Ciprofloxacin, also a fluoroquinolone.

Several advocacy groups are pushing for a more comprehensive animal antibiotic ban in the United States, but Lee said her research plus the evidence from the Baytril ban suggests that approach won’t help.

“They banned Baytril in 2005, and if you look at Baytril resistance in campylobacter now it’s essentially unchanged,” Lee said.

In previous studies, Lee has tried to recreate experimentally conditions that should lead to the swapping of resistance genes among bacteria. Lee said these events – known as the horizontal transfer of genes – do occur, but they may not be as common as initially thought.

What may be driving the antibiotic resistance that Lee has observed in her studies is what’s known as vertical transfer – from parent to child – of bacteria carrying resistance genes. In short, the birds may come to the farm harboring antibiotic resistant bacteria.

“This issue of antibiotic resistance is more complicated than once thought,” Lee said. “These findings suggest that banning antibiotics at the farm level may not be as effective as assumed. We need further studies to identify which management practice would be effective”

Lee stresses that for consumers, the advice on poultry is the same that it’s always been. Cook meat thoroughly and use proper food handling and preparation techniques – washing your hands regularly and keeping other foods away from raw chicken, for example – to minimize the risk of illness.

“All foods have the potential to contain pathogens – all of them,” Lee said. “There’s no substitute for good food handling and preparation.”

The study was funded by grants from the FDA and the United States Department of Agriculture.

Hours after we learned that a wave of illnesses near a small meteorite impact in Peru were terrestrial in origin, a newly published study gave us a big reason to be glad: bacteria can be made deadlier by space travel.

NASA astronauts grew salmonella bacteria during an Atlantis space shuttle mission in 2006, and found that it had become three times as deadly to lab mice as its earthbound equivalents.

Why would that happen? Apparently, it wasn’t the near-zero gravity, at least not directly. The researchers, interviewed by The Associated Press, said that while they are not completely certain, they said the best explanation offered so far had to do with a little-known phenomenon called fluid shear.

Here is how Cheryl Nickerson, an associate professor at the Center for Infectious Diseases and Vaccinology at Arizona State University, explained it to The A.P.:

“Being cultured in microgravity means the force of the liquid passing over the cells is low.” The cells “are responding not to microgravity, but indirectly to microgravity in the low fluid shear effects.”

“There are areas in the body which are low shear, such as the gastrointestinal tract, where, obviously, salmonella finds itself,” she went on. “So, it’s clear this is an environment not just relevant to space flight, but to conditions here on Earth, including in the infected host.”

Still, it’s hardly time to start shipping cases of Purell to the International Space Station. Astronauts have long been wary of microbial growth there, especially after a mysterious fungus started eating through the Mir Space Station.

No one got sick, but the problem was bad enough to prompt a Russian scientist to worry that destroying the station over Earth at the end of its service life could “do serious damage to humanity.” They did it anyway in 2001, and his worry proved unfounded.

NASA has a bunch of precautions for shuttle flights, including testing astronauts for infections, filtering the air onboard for microbes, disinfecting the water supply on the vehicle and keeping the ship spic-and-span with antibacterial wipes.

The results of the salmonella-on-the-shuttle experiment are being published today in the Proceedings of the National Academy of Sciences

Source