Evolution of Ochratoxin A Contents during Storage of Cowpea (Vigna unguiculata L Walp) Bagged PICS with Lippia multiflora Moldenke Leaves and Estimation of Daily Intake in Adult Ivorian

Aims: This study aims to test the effectiveness of the cowpea conservation method in PICS (Purdue Improved Cowpea Storage) bags with a Lippia multifla leaves on the evolution of ochratoxin A and the estimated daily intake in adult Ivorian

Study Design: Cowpea grains that have undergone any treatment were collected between May and June 2015 in the southwest of Côte d’Ivoire. The fresh leaves of Lippia multiflora were collected and dried in sunlight for 7 days in the center of Cote d'Ivoire. The supply PICS bags were made in Abidjan. All this material was sent to the Laboratory of Biochemistry and Food Sciences, Félix Houphouët-Boigny University, Côte d’Ivoire, to perform the experiment. For the experimental realization, 6 conservation methods have been adopted. The first method was conservation of 50 kg of cowpea grain in a polypropylene bag. The second method was conservation of 50 kg of cowpeas in a PICS bag. The other four methods were carried out with PICS bags each containing 50 kg of cowpea grain and different proportions of chopped leaves Lippia multiflora (0.7%, 2.5%, 4.3% and 5% weight of leaves by weight of cowpea). Filling the bags was made by alternating the chopped leaves of Lippia multiflora and cowpea grains as stratum. The six types of packaging were stored on pallets in the warehouse laboratory reserved for this purpose.

Place and Duration of the Study: This study was carried out during June 2015 to February 2016 in the Laboratory of Biochemistry and Food Science, Félix Houphouët-Boigny University, Côte d’Ivoire

Methodology: A central composite design was used for sample constitution. Thus, a control group with polypropylene bags (TSP), a control group in PICS bags without Lippia multiflora (H0) and 4 experimental lots of PICS bags containing different proportions (0.7%, 2.5%, 4.3% and 5% (w / w)) Lippia multiflorarespectively noted H1, H2, H3 and H4, have been used. Changes in moisture, the water activity (Aw) and the levels of ochratoxin A (OTA) cowpea grains stored for 8 months were studied.

Results: The results reveal the presence of OTA in all samples analyzed. However, only 17.65% of the samples had higher levels of OTA than the reference values set by the European Union. PICS bags contain lower levels of OTA. These levels are even lower when the cowpea is stored in PICS bags containing different concentrations of leaves of Lippia multiflora. The estimated daily intake of OTA under the cowpea consumption stored for 8 months were respectively 0.58±0.06 ng / kg body weight/day, 0.66±0.03 ng / kg bw / day, 0.30±0.05 ng / kg body weight / day, 0.30±0.00 ng / kg body weight / day and 0.28±0.00 ng / kg body weight / day for H0, H1, H2, H3 and H4. These levels are below the maximum permissible reference value set by the WHO.

Conclusion: Storage of cowpeas in PICS bags with the leaves of Lippia multiflora appears as a method of effective and inexpensive conservation to ensure the health quality of cowpea.