Theses and Dissertations

Issuing Body

Mississippi State University

Advisor

Nannapaneni, Ramakrishna

Committee Member

Ma, Din-Pow

Committee Member

Schilling, M. Wes

Committee Member

Sharma, Chander Shekhar

Committee Member

Mahmoud, Barakat S. M.

Date of Degree

5-6-2017

Document Type

Dissertation - Open Access

Major

Food Science and Technology

Degree Name

Doctor of Philosophy (Ph.D)

College

College of Agriculture and Life Sciences

Department

Department of Food Science, Nutrition and Health Promotion

Department

Department of Food Science, Nutrition and Health Promotion

Abstract

Center for Disease Control and Food and Drug Administration reports indicate that cantaloupe is one of the five most likely fruits and vegetables to cause a foodborne disease outbreak. Cantaloupe is a potential hazardous food based on the FDA food code since it is capable of supporting pathogen growth due to its low acidity and high moisture content. The objectives of this study were to determine the effect of strain and temperature on growth and biofilm formation of L. monocytogenes and Salmonella spp. in cantaloupe flesh and peel extracts on different food-contact processing surfaces. Growth of L. monocytogenes and Salmonella strains was greater in high cantaloupe flesh and peel extract concentration at 22°C and 10°C. In 50 mg/ml of cantaloupe flesh or peel extract, the cell numbers of L. monocytogenes and Salmonella increased by 5.0-5.5 log CFU/ml in 40 h at 22°C and 1-3.5 log CFU/ml in 72 h at 10°C. In 2 mg/ml of cantaloupe flesh or peel extract, the cell numbers of L. monocytogenes and Salmonella increased by 4.0-4.5 log CFU/ml in 72 h at 22°C but no change in log CFU/ml in 72 h at 10°C. There were no differences (P ˃ 0.05) among L. monocytogenes orSalmonella strains for biofilm formation in cantaloupe extracts, but biofilm formation was greater (P < 0.05) at high temperature and high cantaloupe flesh or peel extract concentration. In 50 mg/ml cantaloupe flesh or peel extract, L. monocytogenes and Salmonella produced biofilms of 7 log CFU/coupon in 4 days at 22°C and 4-5 log CFU/coupon in 7 days at 10°C. In 2 mg/ml cantaloupe flesh or peel extract, L. monocytogenes and Salmonella produced biofilms of 5-6 log CFU/coupon in 4 days at 22°C and 3-4 log CFU/coupon in 7 days at 10°C. L. monocytogenes and Salmonella spp. formed less biofilms (P < 0.05) on buna-n rubber when compared to stainless steel, polyethylene and polyurethane surfaces. These findings indicate that a very low concentration of nutrients that are leaked from cantaloupe flesh or peel can induce growth and biofilm formation in L. monocytogenes and Salmonella spp. on different food-contact surfaces.

URI

https://hdl.handle.net/11668/19217

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