In insects, the hemolymph is the primary site of antimicrobial effectors produced in response to infection. In this study, the antibacterial activity of hemolymph extract from immunized larvae of Oryctes owariensis and Rhynchophorus phoenicis has been evaluated. The tests were carried out on in vitro growth of six bacterial strains including three clinical isolates (Escherichia coli ATCC 25922, Bacillus subtilis, Salmonella spp.) and three strains of food origin (Escherichia coli E1, Staphylococcus aureus S1 and S2 Meti-R). Activity of the different extracts was detected by diffusion method in a gel medium and quantified by macro-dilution technique in a liquid medium. Results showed that the different extracts demonstrate strong antibacterial activity and bactericidal power. Diameters of inhibition zones varied from 19.12±2.88 mm (E. coli ATCC 25922) to 22.58±2.18 mm (S. aureus S1) for the extract from O. owariensis infected larvae. This extract was more active on Gram positive bacteria with a MIC of 12.5 mg/mL and a MBC between 25 and 50 mg/mL. The extract from R. phoenicis infected larvae was very active on all strains with inhibition zone diameters between 26.22±0.69 mm (B. subtilis) and 35.30±2, 4 mm (S. aureus S1). MIC and MBC were respectively developed at the concentrations of 3.12 mg/mL and 6.25 mg/mL on all the bacterial strains. The sensitivity of bacterial strains to these hemolymph extracts reveals the probable presence of produced antimicrobial peptides.

The consumption of salads of the fourth range (4th range) has become increasingly worrying in Abidjan (Côte d'Ivoire). This work was undertaken to determine the microbiological status of these foods during the period of domestic conservation (7°C) after opening the packaging in order to prevent the risk of intoxication from bacterial pathogens. The material and methods used for the microbiological analyses refer to the techniques of classical microbiology followed by statistical tests through R4.1.2 and excel software. The results obtained showed that the 4th range salads sold in the hypermarkets of the city of Abidjan were highly contaminated by bacterial pathogens such as S. aureus with a prevalence of 24%, E. coli O157: H7 with 16% and Salmonella spp. with 18%. On opening the packages (D0), 63.43% of the salads were unfit for consumption, 5% had an acceptable load and 31.57% were of satisfactory microbiological quality. On the third day (D3), the rate of salads unfit for consumption increased (68.43%). On the seventh day (D7), the microbiological quality was the same as on the third day. However, the Salads of the Green Oaks (SChV) and the Meli melo salads (SMe), with perforated packaging were more conducive to the growth of the pathogens studied. Domestic refrigeration does not guarantee the safety of 4th range salads after opening the packages.