Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 2/9/2005
Publication Date: N/A
Technical Abstract: In a mayonnaise-based ham salad, ham is a more likely source than mayonnaise to introduce Listeria monocytogenes into the product. The objective of this study was to evaluate a surface acid treatment for L. monocytogenes-contaminated ham to prevent the possible growth of this pathogen in ham salad during storage at refrigerated and abuse temperatures. Pieces of cooked ham were surface inoculated with an 8-strain mixture of L. monocytogenes, and then dipped in sterile water containing 0% (control), 0.3%, 0.6%, 0.8% and 1.25% acetic acid for 30 seconds. The ham was then mixed with mayonnaise and stored at 4°, 8°, and 12°C. The final cell counts of L. monocytogenes in ham salad were 2.0-3.0 log cfu/g. The counts increased 5.0 log cfu/g in the control after 3 days of storage at 12°C, 5 days at 8°C, and 13 days at 4°C. In salads that supported the growth of L. monocytogenes, an increase of 1.0 log cfu/g and 2.0 log cfu/g after 21 days at 8° and 12°C, respectively, were observed in salads containing ham treated with 0.3% acetic acid, and an increase of 1.0 log cfu/g in salad containing ham treated with 0.6% acid after 21 days at 12°C. Regardless of the storage temperature, L. monocytogenes was unable to grow in salads containing ham treated with 0.8% or 1.25% acid after 21 days. Results indicate that an acetic acid (equal or greater than 0.8%) dip treatment has potential in treating ham used in salad preparation to reduce the concerns of L. monocytogenes growth in ham salad.