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Internet Journal of Food Saety

4/24
2006
ISSUE:207

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FDA RELEASES NEW FOOD SAFETY MANUAL
Managing Food Safety: A Regulator's Manual For Applying HACCP Principles to Risk-based Retail and Food Service Inspections and Evaluating Voluntary Food Safety Management System

Managing Food Safety: A Manual for the Voluntary Use of HACCP Principles for Operators of Food Service and Retail Establishment

FDA¡¯s 2006 Science Forum Commemorates 100 Years of Public Health Science
"A Century of FDA Science: Pioneering the Future of Public Health" is the theme of the Food and Drug Administration (FDA) 2006 Science Forum, being held on April 18-20, 2006 at the Washington Convention Center in Washington, DC.

The Science Forum features top agency scientists and clinicians and their counterparts in industry, academia and other government agencies. The 23 sessions presented at this year's Science Forum include topics that span the breadth of FDA's regulatory responsibilities and current innovative approaches to the regulatory mission of FDA. The sessions include advances in surveillance in medical products, novel approaches to cancer therapy and monitoring, permanent make-up and laser removal, and obesity.

On Tuesday, April 18, to kick off this year's Science Forum, Health and Human Services Secretary Mike Leavitt and Acting FDA Commissioner, Dr. Andrew von Eschenbach will provide opening remarks which commemorate the centennial since the agency's founding. Dr. von Eschenbach will also give a lecture the following day about FDA for the 21st Century. On Thursday, there will be a session on public preparedness, moderated by Maggie Glavin, FDA's Associate Commissioner for Regulatory Affairs. Panelists include Dr. John Agwunobi, HHS Assistant Secretary for Health; Dr. Jesse Goodman, FDA Director of Center for Biologics Evaluation Research, and Dr. Anthony Fauci, Director of the National Institute of Allergy and Infectious Diseases.

FDA is sponsoring a free public session, "Ask FDA," on April 18, 1:30 p.m.?5:30 p.m. This moderated session will answer, in plain language, consumer questions about the regulations of health products that FDA oversees. Attendees will have the opportunity to ask questions of top agency officials.

For more information on the 2006 Science Forum or to register for the event visit www.fda.gov/scienceforum/.


Click here for more information

Prions may not be BSE infectious agents
Source of Article: http://www.ift.org/news_bin/news/news_home.shtml
4/21/2006-Research from the Veterinary Laboratories Agency in Scotland suggests that contrary to previous reports, abnormal prions may not be the infectious agents in transmissible spongiform encephalopathies like BSE, but in fact be a consequence of prion diseases. For more, see the Journal of Pathology article abstract:
http://www3.interscience.wiley.com/cgi-bin/abstract/112568745/ABSTRACT.

FDA Announces Plans for Nanotechnology Public Meeting
The Food and Drug Administration (FDA) will be holding a public meeting in the fall of this year, designed to gather information about current developments in uses of nanotechnology materials in FDA regulated products. In a Federal Register notice displayed today announcing the meeting, FDA asks that those interested in presenting at or attending the meeting inform the agency of their interest.
Nanotechnology is described by the National Nanotechnology Initiative as the understanding and control of matter at dimensions of roughly 1 to 100 nanometers, where unique phenomena enable novel applications. Essentially, nanotechnology is a branch of science devoted to the design and production of extremely small matter.
Due to the small size and special properties of nanotechnology materials, they have great potential for use in a vast array of FDA-regulated products. These small materials often have physical or chemical properties that are different than those of their larger counterparts Differences include altered magnetic properties, altered electrical or optical activity, increased structural integrity, and enhanced chemical and biological properties.
These differences have the potential to lead to scientific advances. For example, this technology could be used to create new drug formulations and routes of delivery to previously inaccessible sites in the body. FDA is holding this meeting to further its understanding of developments in nanotechnology and, more specifically, to hear:
About the new types of nanotechnology products under development in the areas of foods (including dietary supplements), food and color additives, animal feeds, cosmetics, human and animal drugs and human biologics and medical devices;
About any specific scientific issues related to the development of these products relevant to FDA¡¯s regulation of them;Any other issues about which regulated industry, academia, and the interested public may wish to inform FDA concerning the use of nanotechnology in FDA-regulated products; and If there are opportunities for the agency to address hurdles that may be inhibiting the use of nanotechnology in medical product development.
While the agency is not accepting registrations at this time, it would appreciate receiving expressions of interest from those intending to attend or present at the meeting. This information will help FDA prepare and plan for this meeting. Information can be provided to Poppy Kendall at Poppy.Kendall@FDA.HHS.GOV, or 301-827-3360. Based on the level of response, FDA will obtain a venue and structure the meeting to accommodate the audience and range of topics discussed. Details about the venue, specific date, time, and registration will be provided in a Federal Register notice closer to the meeting. You may also look for updates at www.fda.gov/nanotechnology.

Current Job Information
04/21. QC / Regulatory Compliance Supervisor - CA-Central Valley
04/21. R&D - QA Manager - HACCP - Louisville, Jeffersonville, KY
04/21. Quality Control Manager - CA-Sacramento
04/21. DIRECTOR OF QUALITY ASSURANCE - Tampa, FL
04/21. Food Safety Specialist - Denver, CO
04/21. Regulatory Affairs Coordinator - Brunswick, GA
04/20. Quality Assurance Technician - City of Industry, CA
04/20. Quality Assurance Technicians - South Milwaukee, WI
04/20. Quality Assurance Technician - Rockland County, NY
04/19. Laboratory Manager - Food Microbiology - Grand Prairie, TX
04/19. HACCP Coordinator - Oakland, IA
04/19. Quality Assurance Manager - Chicago, IL
04/19. Quality Assurance Supervisor - CA-Calabasas Hills
04/19. QA Manager - Evansville, IN; Louisville, KY
04/19. Plant Quality Control Technician - WA-Bellevue
04/19. CA-San Leandro-QA Supervisor
04/18. MN-Rochester-Senior Microbiologist
04/18. TX-Waco-Microbiology Lab Technician
04/18. Regulatory Affairs Coordinator - Brunswick, GA
04/18. Quality Supervisor - Chicago West, IL
04/18. Microbiologist - IL-South Chicago
04/17. Quality Assurance Supervisor - West Jordan, UT
04/17. CO-Denver-Quality Control Specialist
04/17. Microbiology Laboratory Technician - GA-Atlanta
04/17. QA Lab Technician - NJ-Bridgeton
04/17. QA Mgr, Food and Nutr Mfg - Evansville, IN; Louisville, KY

Benzene in Soft Drinks
FDA is committed to ensuring the safety of food and beverages consumed by Americans and providing timely and factual information when safety questions are raised. We are issuing this statement today to better describe the steps FDA is taking in response to reports that benzene has been found in some soft drinks.
Benzene, a carcinogen, is found in the environment from natural and man-made sources. In November 2005, FDA received reports that benzene had been detected at low levels in some soft drinks containing benzoate salts (an antimicrobial agent) and ascorbic acid (Vitamin C), particularly under certain conditions of storage, shelf life and handling.
FDA's Center for Food Safety and Applied Nutrition (CFSAN) initiated a survey of benzene levels in soft drinks following receipt of the November 2005 reports. This survey indicates that the vast majority of beverages sampled (including those containing both benzoate salts and ascorbic acid) contain either no detectable benzene levels or are well below the 5 parts per billion (ppb) U.S. water standard. The results of this survey, which will be released in the near future, indicate that the levels of benzene in these beverages do not pose a safety concern.
FDA's Total Diet Study (TDS) results from 1995 to 2001, as recently reported by the press, indicated benzene levels in soft drinks that were well above and inconsistent with CFSAN's more recent survey results. The TDS results were also well above and inconsistent with levels reported in previous and current peer-reviewed literature and with hundreds of recent domestic and international government and beverage industry results. We are working to determine the source of the differences. As with any data that appear to be inconsistent, FDA believes it is important to closely examine the reasons for such differences.
The TDS is an ongoing FDA program that determines levels of various contaminants and nutrients in a wide variety of foods. The analytical procedures used in the TDS are designed to detect multiple pesticide residues, industrial chemicals, and toxic and nutrient elements in many foods, not just benzene in beverages. Ongoing investigations into the analytical method used by the TDS suggest that elevated benzene levels can be formed by the procedures used to analyze beverage samples. This raises major concerns about the reliability of the TDS data for benzene in beverages and could explain why these data indicate higher levels of benzene than the levels reported in the more recent surveys by CFSAN and others, as noted above. We are continuing our investigation of the TDS data for benzene, and will make the results available when the investigation is complete.
FDA is also continuing to follow up with companies to ensure that processing conditions are established that will ensure that benzene formation is avoided or minimized.
FDA believes that the results of CFSAN's recent survey indicate that the levels of benzene found in soft drinks do not pose a safety concern.

Codex meeting to debate standards on food additives
By Ahmed ElAmin
Source of Article: http://www.foodproductiondaily.com/
20/04/2006 - Representatives from around the world will meet next week in the Hague, the Netherlands to hash out a common agreement on international standards on food additives and contaminants. The five-day meeting forms part of an ongoing programme to create international food safety standards under the Codex Alimentarius, a body set up by the Food and Agricultural Organisation and the World Health Organisation. The standards could eventually affect the way processors operate worldwide as they become incorporated into national laws. The meeting relates to the Codex General Standard for Food Additives (GSFA), which sets forth the conditions and amounts under which food additives may be used in different food products and processes.
It also relates to a push to lower the amount of contaminants in foods.
Only the food additives listed are permitted for use in foods. Only food additives that have been evaluated by a joint FAO and WHO expert committee and found acceptable for use in foods are included in this standard.

Since 1963, Codex has adopted over 200 commodity standards. Over this time considerable diversity has arisen in the content and format of the food additive sections among these standards, according to documents released ahead of the meeting.
Several committees have developed or are developing standards that reference the GSFA in their food additive sections, for example fermented milks, and canned citrus fruits. These sometimes different approaches taken by the committees needs to be unified under the GSFA, the documents state.
"This diversity in approaches, sometimes by the same committee, contributes to diversity among the food additive sections of Codex commodity standards," the documents stated.
In considering revisions to the food additive section of the Codex commodity standards, the committee proposes to replace the list of food additive provisions in each commodity standard with text that refers to the appropriate food category in the GSFA.
The Codex commodity committees will be asked to prepare a section on food additives in each draft standard. This section would contain a list identifying the functional classes of food additives which are technologically necessary for the specified commodity.
Specific additives and maximum levels of use would only be indicated in cases where exceptional restrictions or permissions are necessary.
Other discussions will centre on the prevention and reduction of aflatoxin contamination in a wide assortment of nuts, the draft maximum levels for lead in fish, cadmium, dioxin, chloropropanols, acrylamide and polycyclic aromatic hydrocarbons.
The background documents for the meeting are available here: http://europa.eu.int/comm/food/fs/ifsi/eupositions/ccfac/ccfac_index_en.html

Dozens of high schoolers exposed to hepatitis A
April 20, 2006
WKYT.com (Kentucky)
The Health Department says it now appears some Tates Creek High School students in Fayette county may have been exposed. 26 freshmen tutored a third grade class at Tates Creek Elementary while a student with Hepatitis A was there. The Health Department will provide free vaccines for those freshmen and the teachers and staff who also may have been exposed.

Lawsuits filed over hepatitis-A outbreak
April 20, 2006
WVLT Volunteer TV (TN)
Jacksboro, Campbell County - Concerns over a Hepatitis-A outbreak last spring in Campbell County are resurfacing, after four people have filed lawsuits against a Jacksboro restaurant they believe may have helped spread the outbreak.
Whitney Daniel has the details of each lawsuit and explains why these people are filing suits almost a year later.
Before this, attorneys say, there wasn't ample evidence pinpointing one particular restaurant as the source of the outbreak. Now, they say Long John Silver's Seafood Shoppe in Jacksboro is the source.
But still, after a year, the East Tennessee Regional Health Department says they have not identified a certain restaurant.
The four plaintiffs are each suing the restaurant, its owner, Lenora Morris and YUM! Brands Incorporated, the company that owns Long John Silver's.
President of the franchise, Dave Carr, gave WVLT this statement:
"Health department officials determined that our Long John Silver's restaurant was not involved in the hepatitis outbreak... Our assessment is that (this lawsuit) is baseless. It's unfortunate that we even have to respond to these claims."

Thai botulism outbreak sickened 163
Source of Article: http://www.cidrap.umn.edu/
Apr 18, 2006 (CIDRAP News) ? The recent outbreak of botulism poisoning traced to bamboo shoots served at a religious festival in Thailand sickened 163 people, according to a report by the US Centers for Disease Control and Prevention (CDC).
Of that number, 141 patients had to be hospitalized, and 10 more were treated as outpatients. A majority experienced abdominal pain, dry mouth, and/or nausea. Forty-two of the hospitalized patients needed mechanical ventilation, the CDC said in the Apr 14 issue of Morbidity and Mortality Weekly Report.
Thai health officials quickly traced the outbreak to a Mar 14 religious rite in Nawaimai Village, Pakaluang subdistrict, Baan Luang district of Nan Province, the report said. Investigators interviewed 145 of the 200 people who had attended the festival about their food intake. The only food in common was home-canned bamboo shoots, which are often eaten with chili and shrimp paste.
The bamboo shoots had been produced locally by a women's group, the CDC wrote. They were processed in large containers that held roughly 26 pounds each. Most of the 53 cans made in September 2005 were sold locally. No other outbreaks have been recorded since those cans were produced.
Antitoxin was not available in Thailand, so Thai officials sought help from several international partners. The United Kingdom (with support form the World Health Organization) sent 20 vials of heptavalent antitoxin; CDC sent 50 vials of bivalent antitoxin; and the National Institute of Infectious Diseases in Japan sent 23 vials of trivalent antitoxin. A Canadian company sold Thailand an additional 10 vials of bivalent antitoxin.
By Apr 10, only 25 patients still remained in the hospital, 9 of them on respirators, the CDC noted. None of the 163 patients died. A study assessing the outcomes of some of the cases is ongoing, the agency noted.
The report said the outbreak occurred 8 years after a smaller botulism outbreak that also was associated with home-canned bamboo shoots. Following that episode, information on safe canning was disseminated throughout the country.
"This recurrence 8 years later indicates the importance of long-term follow up and continuous inspection and assurance of the quality of food canning," the CDC said.

Boundless Love: Grandmother tirelessly cares for E-coli stricken child
April 20, 2006
Palatka Daily News (Florida)
Shai Kuruvilla
INTERLACHEN -- Five years ago, Nancy Doane, 55, adopted her granddaughter, Christen Doane, from foster care.
Christen was once a robust and cheerful baby. Now she is a paraplegic, confined to a wheelchair and dependent on a feeding tube for sustenance. The story says that when Christen was 17 months old, her mother, Juanita Boyd, took her for a quick dinner at a local fast food restaurant, hoping to get back home in time to help her three older children with their homework. She ended up admitting her only daughter to Shands at the University of Florida for three months. Christen was diagnosed with Escherichia coli O157-H7 bacterial disease. While she was in the hospital she suffered from a stroke, which Doane believes was the result of too much medication. The stroke left little Christen severely disabled. Christen was taken from her mother in 1998, when the Department of Children and Families deemed Boyd an unfit mother.
Boyd has three boys and she said DCF thought she was not fit to take care of four children, especially one who is handicapped.

Treatment reduces pathogens in meat
Source of Article: http://www.ift.org/news_bin/news/news_home.shtml
4/21/2006-A mixture of lactic acid bacteria shown to reduce foodborne pathogens such as Salmonella and E. coli O157:H7 in processed beef and poultry by as much as 99.99 percent has passed GRAS (or generally recognized as safe) status review by the Food and Drug Administration.
The mixture, to be sold under the name Bovamine Meat Cultures ¢â, is one of the few post-production treatments available that protects meat and poultry during long-term storage. Administered during the processing phase, it works with other interventions throughout the beef production chain to provide an added layer of protection for consumers.
The treatment was developed through Texas Tech University and is available through Indianapolis-based Nutrition Physiology Corp. Research was funded by the Beef Checkoff Program, the Texas Beef Council and Nutrition Physiology Corp.
¡°Illness rates associated with E. coli O157:H7 have declined steadily over the past ten years. Each sector of the beef production chain has developed and implemented best practices aimed at reducing foodborne bacteria and this lactic acid mixture is another great example,¡± said Mike Engler, Ph.D., Joint Beef Safety Research Committee chairman and Texas beef producer. ¡°It is through the efforts of a united industry, sharing these data and best practices, that we have been able to attack illnesses attributed to pathogens such as E. coli O157:H7 and reduce their occurrence.¡±
The development of the mixture of lactic acid bacteria was led by Dr. Mindy Brashears, associate professor and director of the International Center for Food Industry Excellence at Texas Tech. Tested under conditions simulating meat storage and transfer to and from supermarkets, the product was found to reduce Salmonella by 99.9 percent and E. coli O157:H7 by 99 percent. In addition, the cultures were put through a battery of both subjective and objective taste tests and were shown to have no impact on flavor.
¡°Lactic acid bacteria are considered good bacteria in that they have a lot of benefits,¡± Brashears said. ¡°They are used to make several products like cheese, yogurt and sausages. They have a place in nature and they compete with other bacteria by producing compounds that kill the other bacteria. That is where the concept of using these bacteria to actually reduce foodborne pathogens came from. It is not a new concept, but some of the applications we have developed are unique.¡±
Meat and poultry products containing this mixture will be labeled to reflect the lactic acid cultures used to reduce foodborne pathogens. A link to the FDA¡¯s letter can be found at: http://www.cfsan.fda.gov/~rdb/opa-g171.html

Carbon infrared sterilisers designed for bakery equipment
By Ahmed ElAmin
Source of Article: http://www.foodproductiondaily.com/

18/04/2006 - A new series of carbon infrared emitters can help bakeries speed up the sterilisation of tins, trays and equipment, according to the manufacturer. Infrared disinfection allows plants to use controlled heat targeted at key areas. In bakeries, the first priority is the elimination of mould growth. Radiation emitters direct their heat where it is required and for only as long as needed. The system prevents equipment as well as the baked goods from heat damage, while disinfecting areas. The use of carbon infrared radiation allows heat to penetrate into porous materials or multiple spore layers, Heraeus Noblelight said about its new series of emitters. The machines can be used for eliminating moulds from cake tins, trays and equipment. The carbon infrared emitters use radiation in the medium wavelength region with a high power density. The company cited a study from the Bremerhaven Institute for Food and Bio-processing Technology, which studied the use of the process for six months. The research concluded that infrared radiation can help large bakeries to comply with hygiene standards.

The research showed that, with carbon infrared emitters there is sufficient disinfection of baking trays between 130¨¬C and 140¨¬C in less than 30 seconds. The spore reduction is achieved between 120¨¬C and 160¨¬C within 10 to 30 seconds, depending on the emitter power, the wetness of the tray and the desired speed of operation. "The study showed that the instruments destroyed germs and bacteria safely and in a practicable way," Heraeus Noblelight stated. "Even thick layers of germs, porous surfaces or dust particles did not hamper the process of sterilisation due to the deep penetrating action of the radiation." Muslin tray cloths can also be dried using infrared. This is important when a bakery plant is operated round the clock and it is not possible to carry out drying during the idle phases, the company stated.

"By carrying out this infrared drying in parallel with the disinfection the operating life of the muslin cloths is significantly extended, allowing greater intervals between replacements," Heraeus Noblelight claimed. The devices have power densities up to 150 kW/m©÷ and a response time of seconds. "The fast response times allow for good controllability so that heat is applied for only as long as necessary, drying and disinfection cycles can be programmed and, if there is inadvertent stoppage of the conveyor belt, overheating of the baked goods or the machinery itself is prevented," the company stated. The compact construction of an infrared emitter system, makes it possible for plants to retro-fit infrared disinfection into existing lines, the company claimed.

Carbon infrared technology is also used by bakeries to achieve a browning effect on their products. The technology is suitable for evaporating water from products at a very high power intensity. This ensures that the surface of the food product rapidly achieves a sufficient temperature to drive away local moisture and then causes browning without heating the body of the product. The Bremerhaven Institute is a test centre that performs research and development services for the private sector. The institute focuses on the bakery sector.

Internet Journal of Food Safety (Current Issue)
Vol 8. 23-29
Development of Process for Preparation of Pure & Blended Kinnow Wine
without Debittering Kinnow Mandarin Juice
Vol 8. 19-23
Aspergillus, Health Implication & Recommendations for Public Health Food Safety
Vol 8. 14-18
An Observational Study of The Awareness of Food Safety Practices in Households in Trinidad
Vol 8. 7-13
Antibacterial activity of oregano tea and a commercial oregano water against Escherichia coli O157:H7, Listeria monocytogenes 4b, Staphylococcus aureus and Yersinia enterocolitica 03.
Vol 8. 3-6
Safety and quality practices in closed-house poultry production in Thailand: Lessons from
2004-avian influenza outbreak
Vol 8. 1-2
The introduction of the Japanese Carpet Shell in coastal lagoon systems of the Algarve (south Portugal):
a food safety concern

On-Line Slides
Protection of Food from Adulterants/Proper Labeling, Storage- VIDEO
Dr. Lori Pivarnik
University of Rhode Island
Click here for Windows Media Streaming Versions

Prevention of Cross-Contamination - VIDEO
Dr. Thomas Rippen
Seafood Technology Specialist with the Maryland Sea Grant Program
the University of Maryland Eastern Shore
Click here for Windows Media Streaming Versions (Recommended)
or click here for HTTP Server

USDA/FDA News
Profile Extension Instructions on Food Defense Plans for Meat and Poultry Establishments
Lactic acid bacteria treatment reduces pathogens in meat
Managing Food Safety: A Regulator's Manual For Applying HACCP Principles
Manual for the Voluntary Use of HACCP Principles for Operators of Food Service and Retail Establishments
Manual for the Voluntary Use of HACCP Principles for Operators of Food Service and Retail Establishments (PDF)
Meeting of the Codex Committee on methods of analysis and sampling
Meeting of the Codex Committee on residues of veterinary drugs in foods
AVAILABILITY OF CLEANING FREQUENCY QUESTIONS AND ANSWERS
Statement By Agriculture Secretary Mike Johanns Regarding Canada's Fifth Case Of BSE
GIPSA Updates Alfatoxin Handbook

FDA¡¯s 2006 Science Forum Commemorates 100 Years of Public Health Science
FDA Announces Plans for Nanotechnology Public Meeting
Constituent Update: Apr 14, 2006
Benzene in Soft Drinks
Availability of Revised Versions of Guidance Materials
JOHANNS SIGNS AGREEMENT WITH CHINA ON FOOD SAFETY AND PLANT AND ANIMAL HEALTH
Interstate shellfish dealers certificate
Safe and Suitable Ingredients Used in the Production of Meat and Poultry Products
FSIS Reminds Consumers to Properly Handle and Cook Ground Beef Products
FSIS Issues Amendment to Safe Ingredients List

Researchers Design Antimicrobial, Technique to Watch It
Fri 21-Apr-2006
Source of Article: http://www.newswise.com/articles/view/519808/?sc=rssn
Researchers have designed a new molecule that selectively slashes bacterial cell membranes, leaving the microbes to leak and die. Such compounds could lead to new topical or intravenous antibiotics, or to self-sterilizing materials ranging from countertops to surgical gowns.

Gregory Tew
UMass Amherst scientists can follow the action of a potential antibiotic as it slices into a synthetic bacterial membrane made of phospholipids. The researchers use sum frequency generation (SFG) vibrational spectroscopy, a technique that exploits lasers.
Newswise ? In the continuing battle against drug-resistant bacteria, scientists from the University of Massachusetts Amherst are adding new weapons to the arsenal. Gregory Tew and his colleagues have designed a molecule that selectively slashes bacterial cell membranes, leaving the microbes to leak and die. Such compounds could lead to new topical or intravenous antibiotics, or to self-sterilizing materials ranging from countertops to surgical gowns. The findings are reported in today¡¯s (April 21) issue of the journal Chemistry & Biology.

The research follows work by Tew¡¯s lab and colleagues led by Zhan Chen at the University of Michigan whereby the scientists developed a technique that lets them watch such an antimicrobial knife in action. By following the interaction of a promising antimicrobial molecule with a membrane?in real-time and with relevant quantities?scientists should be able to design more effective antibiotics. The technique was reported in the Journal of the American Chemical Society in February.
Antibiotic resistance has been called one of the world¡¯s most pressing health problems. As scientists seek new compounds for fighting bacterial infections some are turning to the snippets of protein that make up the body¡¯s first line of defense against invading pathogens. Using the structure and conformations of these natural molecules as inspiration, Tew¡¯s team has been designing synthetic antimicrobials in the lab.
Because a molecule that looks well and good on paper might not keep its desired properties once built, Tew also tests his designs using X-ray crystallography and computer calculations. By getting a read on the molecule¡¯s ¡°energy landscape,¡± the researchers can evaluate whether a shape that confers desired slicing powers on paper will maintain that shape once made.

The newly designed antimicrobial compound has a super-stiff backbone, an important structural decision, says Tew, noting that previously researchers focused on the arrangement of the side-chains that are attached to the backbone. The stiff spine yields a compound that has charges distributed in such a way that it is attracted to the water-lipid interface of the bacterial membrane, says Tew.

To test its ability to distinguish friend from foe, the researchers pitted the new compound against microbes such as E. coli and Staphylococcus aureus?the bacterium whose resistant strains plague hospitals?and against human red blood cells. The tests revealed that the new design is indeed both lethal and selective. While it slashed bacterial membranes with zeal, the compound left the human blood cells alone.

Many antibiotics attack a bacterium¡¯s membrane-making machinery, not the membrane itself, says Tew. By taking a hint from nature and mimicking a class of molecules that goes right for the membrane, he hopes bacteria won¡¯t be able to simply tweak their machinery to evade it. The new molecule has shown no propensity for inducing resistance compared to current antibiotics that attack bacteria through more classical routes, he says.

Gaining a better understanding of how these antibiotics work against the membrane will be essential to further improvements, says Tew. So he and Chen used sum frequency generation (SFG) vibrational spectroscopy?a technique that uses lasers and is typically employed by chemists for identifying molecules at surfaces?to further explore the antibiotic-membrane interaction. Tew and Chen have harnessed SFG to explore which molecules pack the strongest antimicrobial punch and how this punch is delivered at the molecular level.

The scientists created a synthetic cell membrane?a bilayer of phospholipid molecules typical of a bacterial cell membrane?and then set the membrane below a clear prism in a trough of water. The researcher then directed two lasers through the prism making the membrane molecules vibrate at specific frequencies. When the researchers injected the antimicrobial compound into the water trough, it sliced into the membrane?a move the researchers monitored via the change in the vibrational frequency bands.

Using SFG lets the researchers watch a potential antibiotic at work?and at concentrations that are meaningful, says Tew. By combining the SFG data with lab experiments on a compound¡¯s bacteria-inhibiting abilities and tests that look at how much cell leakage occurs, researchers will be able to learn more about the molecular interactions governing this antimicrobial activity, he says.

¡°Being able to see how these molecules interact with the membrane at the molecular level in real-time will prove invaluable,¡± says Tew. ¡°This will let us build much better models of how these novel antibiotics interact with membranes?if we understand that, we can build drugs that are more effective and less toxic.¡±