Bacteriological Quality and Risk Factors for Contamination of Raw Mixed Vegetable Salads Served in Collective Catering in Abidjan (Ivory Coast)

The aim of this study was to determine the bacteriological quality of raw mixed vegetable salads served in collective catering in Abidjan and to assess the factors likely to favor contamination. An investigation was conducted to determine the practical risk of contamination. A total of 306 samples were collected and analyzed for the detection and enumeration of Enterobacteriaceae, E. coli and Salmonella according to standard microbiology methods. The most important risk factors were lack of training (96.7%), decontamination (84.0%), cross-contamination of vegetables in contact with fresh chicken or fish (76.7%) and salads that were uncovered and unprotected, thus exposed to the air and at ambient temperature for sale (97.7%). Theprevalence was 100%, 77.8% and 2.6% respectively for Enterobacteriaceae, E. coli and Salmonella. The average load of Enterobacteriaceae and E. coli was 4.93 log10 (CFU/g) and 1.89 log10 (CFU/g), respectively. Unsatisfactory microbiological quality samples were 52.3%. The results showed a failure of the sanitary quality in more than half of the products. Raising awareness in all of the workers in the food chain for vegetable salads is thus necessary to protect the health of the consumers.

Kinetic Approach of Iodine Quantification in Dietary Salts

Iodization of dietary salt is recommended to prevent and control iodine deficiency disorders. The kinetic study of dietary iodized salt proves to be of interest not only for the determination of the conditions of production of iodine, but also for a good knowledge of the kinetic and thermodynamic parameters of the reaction. In this work, two salt brands were studied and one of them was used for the kinetic study. The kinetic study showed that the reaction proceeded slowly at a medium rate. Since the reaction admits a global order equal to 1, potassium iodide has no influence on this reaction rate. The concentration of iodate ions introduced in the dietary salt is a kinetic parameter that affects the reaction rate. Calculated rate constant was inversely proportional to time. The study has therefore determined experimentally kinetic parameters of the reaction between iodate and iodide ions.

Modeling of Copper Adsorption by <i>Moringa oleifera</i>Seed Powders

In this work, an inexpensive and environmentally friendly natural adsorbent obtained from shelled (GD) and unshelled (GND) Moringa oleifera seeds was used for copper adsorption from aqueous solutions. A series of experiments were performed to assess the parameters influencing the adsorption phenomenon such as pH, adsorbent mass, adsorption equilibrium time and temperature. The kinetic results of adsorption described a pseudo-second order model. The adsorption isotherms are satisfactorily described by the Langmuir mathematical model. The thermodynamic data revealed a spontaneous and endothermic adsorption phenomenon. The level of copper in surface water before and after addition of moringa powders was carried out to verify the effectiveness of the adsorbent. A maximum adsorption rate of 51.28% and 61.96% was obtained with GD and GND powders respectively. Moringa oleifera seed powders are an effective alternative for the removal of copper from surface water.

Retention Factors for Trace Metal Elements in Solid Phase and Applicable Adsorption Models: Case of <i>Moringa oleifera</i>

Moringa oleifera is an edible plant cultivated throughout the tropical belt. It belongs to the family Moringaceae and is one of its 14 known species. This paper presents a synthesis of the main factors responsible for the retention of trace metal elements (TMEs) by Moringa oleifera seed powder, a natural adsorbent. The five main factors studied are metal concentration, solution pH, adsorbent particle size, adsorbent dose and adsorbent/adsorbate contact time. Through these factors, we present the optimal conditions for removal of these TMEs, as well as adsorption isotherm models appropriate for the conditions of retention of these metal cations by the adsorbent. The times of 20 min (GD) and 50 min (GND) are the equilibrium times obtained in our study. An optimal adsorbent mass (GD and GND powders) of 4.5 g was found. 20% to 97% abatement is observed for average pH values between 6 and 8. The coefficients of determination (R2) obtained (0.972, 0.963, 0.991 and 0.799) during the isotherm experiments carried out at 20°C, 30°C, 40°C and 50°C are close to 1. Also, the separation factor (RL), an essential characteristic of the Langmuir isotherm whose values are between 0 and 1, attest to the applicability of the Langmuir isotherm model to fit the experimental data of copper adsorption by Moringa powders. In this paper, we are particularly interested in the following TMEs (Mn, Ni, Cr, Cu, Cd, Co, Pb, Fe, Zn, Ag).