Antibody Cocktail Targets Deadly Foodborne Germs

EMBARGOED FOR RELEASE: Sunday, March 23, 10:30 a.m., Central Time

In the future, consumers may be adding a powerful "spice" to their food that could save lives. Researchers in Canada are developing a natural antibody cocktail that can help prevent the most common foodborne germs, including E. coli and Salmonella, which cause thousands to become sick or die each year in this country.

Derived from freeze-dried egg yolk, the substance is nicknamed a spice because it can be sprinkled or sprayed onto meats, fruits and vegetables to complement existing sanitation protocols. The so-called spice does not alter the taste of food.

Food contamination is on the rise in this country and is increasingly seen as a possible means of bioterrorism. One of the pathogens cited by the World Health Organization as a possible agent of bioterrorism is Salmonella, which this spice could protect against, the researchers say.

Research on the compound, which appears promising in early animal tests, was described today at the 225th national meeting of the American Chemical Society, the world's largest scientific society.

"This spice represents a safe, easy and inexpensive way to enhance your protection against deadly germs that attack humans via food. One day, it will be found in everyone's spice cabinet," says Hoon Sunwoo, Ph.D., chief investigator in the study and a food chemist at the University of Alberta in Canada.

"This spice does not kill the germs, but prevents them from infecting your body," says Sunwoo. The antibody can remain active one to two hours after being ingested. "That buys precious time that can help keep you alive," he adds.

As with the flu vaccine, hens are injected with specific foodborne pathogens, such as E. Coli, Salmonella, Campylobacter, Staphyloccoccus and Listeria. The animals then develop antibodies, called IgY (immunoglobulin Y), to these pathogens as their immune system attempts to attack them. These antibodies tend to accumulate in large amounts in the egg yolk, which is then collected, processed and freeze-dried to form a natural, germ-fighting cocktail.

Unlike the flu vaccine, which contains inactive viruses, the antibodies found in the spice are nonliving and pose no risk of infection.

Germs normally target and bind to the intestine, causing infection. In the presence of the antibody cocktail, the germs bind to their corresponding antibodies. The antibody-germ complex is then eliminated as waste, preventing infection.

More tests are needed before the spice is ready for consumer use, the researcher says. If all goes well, human tests could begin within a year, says Sunwoo. Early tests show that the spice can remain active in a freeze-dried condition for up to two years.

The spice will be most useful when traditional sanitation safeguards (i.e. rinsing, refrigeration, and thorough cooking) are unavailable or unreliable, the researcher says. Possible uses: foods that are prepared outdoors or meals that are eaten away from home, especially at salad bars and food bars.

The spice could be helpful for travelers to foreign countries in which food-handling practices are suboptimal. It can even be added to beverages, including water and fruit juice, says Sunwoo.

At the industrial level, the spice can be dissolved in water and sprayed onto meat carcasses to complement other processing methods, such as irradiation, or applied to final packaging. Such extra-protection methods would be welcome news for an industry that has been recently plagued with record-high meat recalls, says Sunwoo.

Although summer is the peak season for food contamination, cases can occur throughout the year. Consumers are urged to continue practicing safe-food handling techniques to reduce their chances of developing foodborne illness. People most vulnerable to serious complications from foodborne illness include infants, the elderly, pregnant women and those with weakened immune systems.

Antibodies can be developed for virtually any foodborne germs, including viruses, the researcher says. One possible candidate is the norovirus, which has recently been linked to a rash of outbreaks of flu-like illnesses on cruise ships.

Funding for this study was provided by the Natural Sciences and Engineering Research Council of Canada (NSERC).

The paper on this research, AGFD 10, will be presented at 10:25 a.m., Sunday, March 23, at the Hampton Inn-Convention Center, Riverside II, during the symposium, "Immune-Enhancing Foods."

Hoon H. Sunwoo, Ph.D., is a research associate at the University of Alberta, Department of Agricultural, Food and Nutritional Science, in Edmonton, Alberta, Canada. -- Mark T. Sampson

EMBARGOED FOR RELEASE: Sunday, March 23, 10:30 a.m., Central TimeAGFD 10 IgY technology for human health: Antimicrobial activities of IgY preparations against foodborne pathogensHoon H. Sunwoo, and Jeong S. Sim, Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB T6G 2P5, Canada,

Whole egg yolks and water soluble fractions were prepared from the laying hens that had been immunized with pathogens such as E. coli O157:H7, Salmonella enteritidis, Salmonella typhimurium, Campylobacter jejuni, Staphylococcus aureus, and Listeria monocytogenes which cause foodborne illness. The anti-microbial effects of these preparations were investigated by growth inhibition assay and immuno-electron microscopy in a combination with ELISA. The preparations containing specific egg yolk antibodies (IgY; ranging from 14 to 66 mg/ml) showed a strong affinity for pathogens and demonstrated bacteriostatic activity against pathogens. It showed that pathogen-specific IgY was bound to the surface of bacteria, resulting in structural alterations of cell wall. The neutralizing effects of IgY preparations were preserved over 2 yrs in freeze-dried condition. Incubation at pH of 2.0 for 4 h led to about 65% reduction in the amount of pathogen-specific IgY. The activity of pathogen-specific IgY was also not significantly affected by enzymatic digestions such as trypsin or chymotrypsin at 37oC for 4 h.

EMBARGOED FOR RELEASE: Sunday, March 23, 10:30 a.m., Central TimeAGFD 10

IgY technology for human health: Antimicrobial activities of IgY preparations against foodborne pathogens

*Briefly explain in lay language what you have done, why it is significant and its implications, particularly to the general public.

Natural antimicrobial agents in food have been recognized for many years, but the use of such bioactive compound has been scientifically emerged only in recent years. One such antimicrobial agent is IgY, a major antibody in egg yolk of laying hens. Chicken egg yolk has received much attention as a good source of antibodies, because eggs can be collected in a daily basis and a single egg contains over 200 mg of IgY. Another advantage of IgY use offers greater compatibility with animal welfare regulations as alternative to conventional antibody production methods bleeding from animals. As a food ingredient or agent, therefore, IgY can be used as prophylactic, therapeutic and diagnostic agents. To achieve this goal, my research interests pertaining to the use of IgY have focused on:

1) Prophylactic Treatment of IgY: Microbial food-borne diseases are responsible for serious health problems in humans and animals. In order to develop efficacious procedures for prevention and treatment of food-borne diseases, research in our laboratory has focused on the production of specific IgY against food-borne pathogens such as Escherichia coli O157:H7 (J.Food Sci. 67:1486-1494, 2002), Salmonella spp.(Poultry Sci. 81:632-641, 2002), Listeria spp., Campylobacter spp., enteropathogenic E. coli 987P, viruses and parasites. The results have demonstrated that specific IgY against E. coli O157:H7 and Salmonella is able to inhibit the growth of pathogens, eventually resulting in bacterial death. The amount of specific IgY when administered orally reduces to 65%, but the rest of IgY is still active under the acidic conditions and enzymatic digestions. We found that the neutralizing effects of IgY preparations could be preserved over 2 yrs in freeze-dried condition. This research offers many advantages over traditional antibiotics and will probably provide the basis of a highly effective means of producing inexpensive antibodies in egg yolks as functional food and nutraceutical ingredients for the prophylactic treatment of humans and animals against enteric diseases. It may also be the potential standard procedure to remove or reduce the health risk of pathogens contaminated in beef and food products. Most raw North American meat processed into ground beef patties may be tainted with the illness-causing E. coli O157:H7. It is also reported that over 60% of beef cattle in North America are infected and shedding E. coli O157:H7 bacteria to the environment. The public health importance of E. coli O157:H7 depends on the prevention of the bacterial contamination on the beef carcass. In this matter, a new approach to food safety is being investigated whether IgY can be sprayed onto carcass to help prevent bacterial contamination during processing or can be applied to a final packaging to inhibit bacterial growth and extend shelf life. A new concept of IgY cocktail, pool of specific IgY against food-borne pathogens mentioned above, will be applied to the development of IgY spice for the preventing bacterial infections from beef, salad, and other food products.

2) Development of Diagnostics: My research interest has focused on the development of several ELISAs that can be used to determine the detection and quantification of food-borne pathogens, hormones, pesticide residues, antibiotics, mycotoxins, and glycoproteins in animal and food products. IgY technology allows large batches of highly specific IgY to be available for this purpose. Our research have shown that an indirect competitive ELISA IgY is very sensitive to quantitate the level of lactoferrins between human and bovine and proteoglycans as extracellular matrix components in connective tissues (Can.J.Anim.Sci. 78:287-291, 1998). A rapid and reliable sandwich ELISA technique using IgY as the capture antibody has been also developed to detect the E. coli O157:H7 ranged from 101 cfu to 1012 cfu in meat products. This study is urgently needed in beef industry. In addition, ELISA using IgY can be prepared as commercial test kits for rapid screening of a variety of compounds in animal and food products. Furthermore, the IgY technology can be diversified into the biomedical applications in the area of immuno-therapeutic research for the treatment of shiga toxins derived from enterotoxigenic E. coli and for the detection of cancer marker proteins as a cancer diagnostic kit.

3) Production of IgY: Factors such as immunization protocols, biological modification of feeding and nature of hens are crucially important to efficiently produce a large amount of IgY without giving stress to chickens. Immune response in laying hens could be stimulated by adjuvant formulas, different epitopes of antigens, and immunization schedules which influenced the production of IgY in egg yolks (Poultry Sci. 75:342-345, 1996). We also found that the egg yolk weight and the percent hen-day production, both of which were greater in Single Comb White Leg Horn hens than in Rhode Island Red hens, are important factors for the efficient production of specific IgY (Poultry Sci. 77:266-270, 1998). The level of immunoglobulin content in serum and egg yolk was enhanced by manipulating animal feeding with different levels of omega-3 fatty acids (Can.J.Anim.Sci. 80:597-604, 2000). Further factors such as antigen treatment (Formalin or heat treatment for bacteria inactivation), injection routes (i.m., s.c., i.d., and oral administration) and antibody purification (water soluble fraction, liposome and encapsulation) are being investigated.

* How new is this work and how does it differ from that of others who may be doing similar research?

Most IgY studies have been investigated on the passive immunization of oral administration of IgY to prevent the bacterial infection related to diarrhea in animals. The effectiveness of IgY on anti-microbial activity, potential prophylactic or therapeutic treatment has been widely proven by many researchers including my laboratory around world. My research is unique in that IgY can be produced in the efficient and economical ways for meeting industrial needs and applied to food sanitizing system as potential and natural antimicrobials which is extremely powerful tool that prevent microbial growth and attachment on beef carcass or other food products.

* Indicate if the material in your presentation (or similar research) has received prior media coverage and, if so, which publications or broadcast stations might have reported it.

- Unless otherwise indicated above, all information is new.

* Corresponding author's name and business title or position:Hoon H. Sunwoo, Ph.D.Research Associate

* Work department:- Department of Agricultural, Food and Nutritional Science