89D-16 |
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W. S. MULLER, A. Sikes, A. L. Allen, K. Racicot, and A. G. Senecal. U.S. Army Natick Soldier Center, U.S. Army Research, Development & Engineering Command, Kansas St., Natick, MA 01760-5020 Taro and its natural fermented end product, poi, are products native to tropical and sub-tropical regions such as Hawaii. A closer examination at the physical/chemical properties of these products indicates a potential broader use of these in both military and commercial foods. This study focuses on the functionality of fermented taro as an antibacterial ingredient for intermediate moisture (IM) products. The method for preparation of the fresh taro corm for fermentation is similar to the preparation of poi in which the taro corm is skinned, ground and cooked to form the taro medium. The taro is then inoculated with a food grade bacterium that produces a bacteriocin, forming the fermented taro product. Lactococcus lactis ssp. lactis, a nisin producer, has been the main bacteriocin producer studied with the IM product (burrito). L. lactis yielded nisin concentrations of approximately 16,000 AU/g of taro. A challenge study was conducted in which the fermented taro was incorporated into the burrito at 600 and 1200 AU/g of burrito. The challenge organisms consisted of three strains of Staphylococcus aureus and were at an inoculum level of 2 x 105 cells/g of burrito. Within 7 days, the control, having unfermented taro, showed a two log increase in the S. aureus counts and by the 14th day increased further to 3 x 108 cells/g. The burrito samples treated with 600 AU/g of fermented taro, showed no increase in the bacterial counts after 7 days. However, after 14 days the cell count increased to 3 x 107 cells/g. The burrito samples treated with 1200 AU/g of fermented taro showed no increase from the original inoculum level during the 56 day study. The incorporation of fermented taro can potentially provide an effective food preservation technique for military and commercial IM products.
Session 89D, Food Microbiology: Antimicrobial effects on foodborne microorganisms
2005 IFT Annual Meeting, July 15-20 - New Orleans, Louisiana |