title: Survival and growth of Salmonella Typhimurium, Escherichia coli O157:H7 and Staphylococcus aureus in eggplant dip during storage.
abstract: Eggplant dip is an internationally popular appetizer, prepared in some instances under uncertain hygienic conditions with inconsistent refrigeration. This study examined the effects of citric acid on the survival of pathogenic microorganisms (Salmonella Typhimurium, Escherichia coli O157:H7 and Staphylococcus aureus) and naturally present organisms (lactic acid bacteria, LAB, aerobic bacteria, APC and yeast and mold, YM) in eggplant dip during storage. Eggplant dip with 0, 0.2, 0.4, 0.6 or 0.8% citric acid was inoculated with S. Typhimurium, E. coli O157:H7 or S. aureus and stored at 4, 10 and 21 °C for ≤15 d. Throughout the study, the survival of the inoculated microorganisms was monitored, and LAB, APC, YM numbers and pH were determined. There was no significant (p>0.05) effect of citric acid on inoculated S. Typhimurium and E. coli O157:H7. Salmonella and E. coli O157:H7 survived >7d with little reduction in viability. Reduction of S. aureus viability increased with citric acid concentration and reached>3.0 log10 CFU/g by 15 d at 4 °C. Citric acid had no effect (p>0.05) on the background YM during storage at 4, 10 and 21 °C or LAB stored at 4 and 10 °C, while at 21 °C, 0.6 and 0.8% citric acid significantly reduced LAB. Citric acid had no effect (p>0.05) on the APC in samples stored at 4 °C but it had significant effects on samples stored at 10 and 21 °C. Work reported showed that the use of citric acid at 0.4-0.8% can inhibit the growth of S. aureus in eggplant dip, but adequate refrigeration is essential to minimize risk from this and other pathogens in this product.
authors.affiliation: Department of Nutrition and Food Technology, Jordan University of Science and Technology, Irbid 22110, Jordan. Electronic address: tosaili@just.edu.jo.
authors.forename: Tareq M
authors.initials: TM
authors.lastname: Osaili
authors.affiliation: Department of Nutrition and Food Technology, Jordan University of Science and Technology, Irbid 22110, Jordan.
authors.forename: Anas A
authors.initials: AA
authors.lastname: Al-Nabulsi
authors.affiliation: Department of Nutrition and Food Technology, Jordan University of Science and Technology, Irbid 22110, Jordan.
authors.forename: Ziad
authors.initials: Z
authors.lastname: Jaradat
authors.affiliation: Department of Nutrition and Food Technology, Jordan University of Science and Technology, Irbid 22110, Jordan.
authors.forename: Reyad R
authors.initials: RR
authors.lastname: Shaker
authors.affiliation: Department of Nutrition and Food Technology, Jordan University of Science and Technology, Irbid 22110, Jordan.
authors.forename: Dalia Z
authors.initials: DZ
authors.lastname: Alomari
authors.affiliation: Department of Nutrition and Food Technology, Faculty of Agriculture, The University of Jordan, Amman 11942, Jordan.
authors.forename: Maher M
authors.initials: MM
authors.lastname: Al-Dabbas
authors.affiliation: Department of Veterinary Pathology and Public Health, Faculty of Veterinary Medicine, Jordan University of Science and Technology, Irbid 22110, Jordan.
authors.forename: Akram R
authors.initials: AR
authors.lastname: Alaboudi
authors.affiliation: Department of Veterinary Pathology and Public Health, Faculty of Veterinary Medicine, Jordan University of Science and Technology, Irbid 22110, Jordan.
authors.forename: Mohammad Q
authors.initials: MQ
authors.lastname: Al-Natour
authors.affiliation: Department of Food Science, University of Manitoba, Winnipeg, MB R3T 2N2 Canada.
authors.forename: Richard A
authors.initials: RA
authors.lastname: Holley
mesh_terms: D019343:Citric Acid / Q000494:pharmacology; D015169:Colony Count, Microbial; D019453:Escherichia coli O157 / Q000187:drug effects / Q000254:growth & development / Q000502:physiology*; D005516:Food Microbiology; D005520:Food Preservatives / Q000494:pharmacology; D061353:Food Storage; D012034:Refrigeration; D012486:Salmonella typhimurium / Q000187:drug effects / Q000254:growth & development / Q000502:physiology*; D032323:Solanum melongena / Q000382:microbiology*; D013211:Staphylococcus aureus / Q000187:drug effects / Q000502:physiology*
chemical_list: D005520:Food Preservatives; D019343:Citric Acid
keywords: Citric acid; Eggplant dip; Escherichia coli O157:H7; Food safety; Salmonella Typhimurium; Staphylococcus aureus