Application of Selected Natural Antimicrobial Formulations for the Control of Food Pathogens in Fresh-Cut Cauliflower

In recent years, research on biopolymer based-coating containing natural antimicrobial agents is developing significantly. The objective of this study was to evaluate the antimicrobial efficiency of six formulations containing pre-selected natural antimicrobial compounds against Listeria monocytogenes, Escherichia coli O 157：H7, Salmonella typhimurium, the total bacteria and total yeasts and molds in cauliflower. Each formulation was subjected to a sensory test in parallel to microbiological analysis and the efficiency during storage at 5 ℃ was evaluated for the two best formulations, based on their ability to eliminate the target microorganisms. Both formulations were able to reduce all pathogens and total flora below detectable levels after 24 h of storage at 5 ℃. Using washing or spraying treatments, the two formulations were able to reduce Listeria to undetectable levels for 3 d. This efficiency was extended to 7 d when the formulations were incorporated into an edible coating. Washing treatment with the two formulations was also able to limit the growth of yeast and molds at levels lower than 2 log, for more than 7 d. The population of E. coli was reduced to below the detection limit during 14 d of storage, after washing treatment with the two formulations. The spraying treatment of cauliflower with the formulations allowed the use of very small amounts of antimicrobials while maintaining a fairly good efficiency, greatly reducing the potential costs of implementing this method in the industry. Future research may focus on development of nanoemulsion of antimicrobial formulations based on the developed antimicrobial formulations in this study to improve the better coating efficiency.

Antimicrobial Profile of Lactic Acid Bacteria Isolated from Vegetables and Indigenous Fermented Foods of India against Clinical Pathogens Using Microdilution Method

In dairy and food industries lactic acid bacteria （LAB） have been used in form of starter culture that plays vital role in fermentation; as flavouring and texturizing or as preservative agents. There is increasing evidence that lactobacilli which inhabit the gastrointestinal tract develop antimicrobial activities and participate in the host＇s defence system[1]. During fermentation, most of the LAB produces a number of different compounds like organic acids, hydrogen peroxide, diacetyl, acetaldehyde, carbon dioxide, polysaccharides, and proteinaceous compounds called bacteriocins or bacteriocinogenic peptides.

Nanoparticles based sensors for rapid detection of foodborne pathogens

Rapid detection of foodborne pathogens is a key step in the control of food related diseases.Conventional methods for the detection of food pathogens,although typically sensitive,often require multiple time-consuming steps such as extraction,isolation,enrichment,counting,etc.,prior to measurement,resulting in testing times which can be days.There is a need to develop rapid and sensitive detection methods.This review is intended to provide food scientists and engineers an overview of current rapid detection methods,a close look at the nanoparticles especially magnetic nanoparticle-antibody conjugates based methods,and identification of knowledge gaps and future research needs.

Antibacterial potential of Thevetia peruviana leaf extracts against food associated bacterial pathogens

Objective:To isolate and characterize the food associated bacterial strains,and to evaluate the antibacterial activity and minimum inhibitory concentration of various solvents(acetone,chloroform,methanol and petroleum ether)leaf extracts of Thevetia peruviana(T.peruviana)against their respective isolated and standard bacterial strains and also to investigate the presence of various phytochemical constituents in the leaf extracts of test plant.Methods:The food associated bacterial strains were isolated from students'lunch boxes in Tesfa Tewahido Primary School.The antimicrobial activity and minimum inhibitory concentrations were determined by the disc diffusion and serial dilution methods,respectively and phytochemical constituents were also detected in various solvent leaf extracts of T.peruviana.Results:The result showed that all the tested solvent leaf extracts of T.peruviana exhibited antibacterial activity against the tested standard and isolated bacterial strains with zones of inhibition ranged from 10.0 to 17.0 mm.Amongst the tested food borne bacterial pathogens,Salmonella typhimurium was most sensitive towards petroleum ether leaf extracts of T.peruviana while,methanol leaf extracts was relatively least effective against all the tested standard and isolated bacterial strains.Minimum inhibitory concentration of various solvent leaf extracts of T.peruviana ranged from 16.67 to 50.00 mg/mL for all the tested standard and isolated bacterial strains.The phytochemical constituents screening on the leaf extracts of T.peruviana showed the presence of alkaloids,cardiac glycosides,flavonoids,polyphenols,saponins and tannins.Conclusions:The present study suggests that T.peruviana could be used as prospective aspirants against the common food borne bacterial pathogens and also provide a wide array in the development of drugs against common food borne bacterial pathogens.