Comparative study of antibiofilm activity of lime juice and lithium dioxide nanoparticles against Salmonella isolated from local cheese

Zainab Zamel Khalaf

doi:10.24126/jobrc.2018.12.2.542

Abstract

Thirty specimens of fresh white cheeses, presented for sale in different markets at different cities of Iraq were analyzed microbiologically in this study. Isolates of Salmonella, included in the specimens collected from November 2017 to January 2018, were investigated. Capacity for biofilm producing was demonstrated by two method, Tissue culture plate method (TCP) and Congo red agar (CRA).After that the antibiofilm activity of lime extract and LiO2NPs was studied as each one of them alone and then the synergistic effect was done by TCP method. The results showed that all Salmonella isolates produce biofilm but in different degrees. The results also displayed that Lime extract and LiO2NPs had antibiofilm effect against Salmonella when used alone and when the combination done between each one of these materials. In conclusion, it was observed that the specimens of fresh white cheese included in this study contained microbial contamination at a health-threatening level but we can eliminate this contamination by using lime extract and LiO2NPs.

Highlights

Cheese is an excellent source of protein, fat and minerals such as calcium, iron and phosphorus, vitamins and essential amino acids and is an important food in the diet of both young and old people [1, 2]
Isolation and identification: The results of present study showed the presence of 84 isolates belong to different bacterial species in cheese samples, Data revealed that (19.04%) of the cheese samples were contaminated with Salmonella enterica serovar typhi
In the United States, analysis of epidemiological data on food borne disease outbreaks indicated that Salmonella is the most common bacterial etiologic agent, accounting for 52% of outbreaks attributed to bacteria [26]

Summary

Introduction

Cheese is an excellent source of protein, fat and minerals such as calcium, iron and phosphorus, vitamins and essential amino acids and is an important food in the diet of both young and old people [1, 2]. It’s produced throughout the world in wide-ranging flavors, textures, and forms [3]. The characteristic flavor of cheese is achieved by the addition of starter culture such as lactic acid bacteria which are produced lactic acid from lactose, so the cheese was fermented [4]. Cheese is a nutrient that is quite rich in protein and calcium, so it is exhibit a very rapid growth of microorganisms which infect through various sources [5]. Salmonella enterica, Escherichia coli O157:H7 and Shigella spp. are among the major food borne pathogens affecting people worldwide [7]

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Results