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Title: Inhibition of Biological Activity of Staphylococcal Enterotoxin A (SEA) by Apple Juice and Apple Polyphenols

Author
item Rasooly, Reuven
item Do, Paula
item Friedman, Mendel

Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/9/2010
Publication Date: 4/19/2010
Citation: Rasooly, R., Do, P.M., Friedman, M. 2010. Inhibition of Biological Activity of Staphylococcal Enterotoxin A (SEA) by Apple Juice and Apple Polyphenols. Journal of Agricultural and Food Chemistry. 58:5421-5426.

Interpretive Summary: Staphylococcal enterotoxins (SEs) produced by the pathogenic bacteria Staphylococcus aureus cause food poisoning. This paper demonstrated that freshly prepared Red Delicious apple juice can inhibit the biological activity of Staphylococcal enterotoxin A, a representative of the superantigen-released by S. aureus that is associated with 78% of staphylococcal outbreaks in the USA. We also found that the Red Delicious juice has an inhibitory effect even after washing and removal of juice from the toxin and even 48 h after the toxin has activated the spleen cells. The described findings suggest that apple juice has the potential to counteract adverse effects in animals and humans induced by staphylococcus enterotoxin A.

Technical Abstract: The foodborne pathogen Staphylococcus aureus produces the virulent staphylococcal entertoxin A (SEA), a single-chain protein that consists of 233 amino acid residues with a molecular weight of 27 078 Da. SEA is a superantigen that is reported to contribute to animal (mastitis) and human (emesis, diarrhea, atopic dermatitis, arthritis, and toxic shock) syndromes. Changes of the native structural integrity may inactivate the toxin by preventing molecular interaction with cell membrane receptor sites of their host cells. In the present study, we evaluated the ability of one commercial and two freshly prepared apple juices and a commercial apple polyphenol preparation (Apple Poly) to inhibit the biological activity of SEA. Dilutions of freshly prepared apple juices and Apple Poly inhibited the biological activity of SEA without any significant cytotoxic effect on the spleen cells. Additional studies with antibody-coated immunomagnetic beads bearing specific antibodies against the toxin revealed that SEA added to apple juice appears to be largely irreversibly bound to the juice constituents. The results suggest that food-compatible and safe anti-toxin phenolic compounds can be used to inactivate SEA in vitro and possibly also in vivo, even after induction of T-cell proliferation by long-term exposure to SEA. The significance of the results for microbial food safety and human health is discussed.