Implementation of membrane processes for improvement of the detection of food contaminants

Abstract

Food borne pathogen is a topmost important concern of present era due to deteriorating the food quality, contributing significant loss in the health aspect, global nutritional demand and economy. A rapid, fast and effective analytic system of pathogen identification and enumeration is the vital most important tool towards minimization of both the grasp and effect of pathogen contamination whereas the performance and accuracy of almost all of presently developed respective sensory tools are localized on the molecular recognition and catalytic processes of the sensor that work for the detection and enumeration. The presence of other biological molecules except the targets imparts significant unwanted ligand interaction which deteriorates its true binding efficiency of the specific ligand with exact orientation and frequency; and thus requires the pre-treatments of the sample to minimize such interference. Keeping this on mind, in this work, a membrane process has developed for the purification of the targets (the cells) by removal of the other unwanted interfering species from the Listeria innocua loaded food (milk) sample followed by concentration of the sample. Both the type of bacteria and host food were selected due to high demand. The selective concentration of the cells and volume reduction of target cells from the milk sample was accomplished by diafiltration (DF) and tangential flow filtration (TFF) with microfiltration (MF) membrane. The effect of cell loading on the cell purification and concentration by filtration performance of milk was analyzed. Comparative analysis between TFF and DF was done on this aspect and a combined protocol has developed. The analysis of operational parameters (e.g. TMP, CFV, permeate flux behaviour, system configuration, etc.) on the chemical composition of permeate and retentate was studied. A mass-balance based model was developed and used to predict the trend of concentrations of the species along the progress of DF process. The organic load removal from the system was found to be positively correlated with the TMP and CFV involved while the cell recovery was found efficient in an optimum TMP range. The system was found efficient with fastness, effective cell purifying and concentrating capability, high recovery of membrane and easiness to operate with more than 99.7% of viable cell isolation for further use in bio-sensing tool.