Bacterial and parasitic contaminants of salad vegetables sold in markets in Fako Division, Cameroon and evaluation of hygiene and handling practices of vendors

Abstract

Objective: Increase in awareness of the health benefits of vegetables has resulted in an increase in consumption. Many vegetables are consumed raw to retain the natural taste and heat labile nutrients. The safety of raw vegetables is a great concern. We investigated the bacteriological and parasitological quality of salad vegetables sold in three major markets in Fako Division Cameroon, the hygiene and preservation practices of vendors and determined the antimicrobial sensitivity of bacterial isolates, to provide data that could be used to improve food safety and safeguard public health.

Results: Bacterial contamination was high. Mean aerobic bacteria counts ranged from 2.5 × 10⁶ to 15 × 10⁶ cfu/g, total coliform counts from 4 to > 2400/g and fecal coliforms < 3 to 1100/g. Six bacterial species were isolated among which Staphylococcus aureus (35.4%) predominated while Serratia marcescens (8.5%) was the least. Bacteria showed high resistance to erythromycin (87.6%). Ten parasitic organisms were detected. Balantidium coli (25.6%) and Entamoeba spp. (21.7%) predominated. Contamination was highest in lettuce and lowest in green pepper. Hygiene and vegetable preservation practices of vendors were poor and could aggravate contamination. Contamination of fresh salad vegetables with pathogenic bacteria and parasites could be a food safety concern in study area.

Keywords: Antibiotic resistance; Cameroon; Hygiene practices; Intestinal parasites; Pathogenic bacteria; Salad vegetables.

Fig. 1

Mean aerobic bacterial counts (× 10⁶ CFU/g) of samples from study sites. Mean aerobic bacterial load of samples was generally high. Highest counts occurred in leafy vegetables green cabbage (GC), red cabbage (RC) and lettuce (LE) compared to non-leafy cucumber (CU), green pepper (GP) and carrots (CA). Number of each sample analyzed (n) = 30. ANOVA test gave a significant difference (P = 0.00) in counts between vegetables

Fig. 2

Distribution of bacteria isolates in samples. Six species of bacteria, mostly enteric organisms were detected in vegetables. S. aureus, the only non-enteric organism was the most frequently isolated. All six species were present in all types of vegetables. Only C. freundii (X² = 16.118, P = 0.007) showed significant differences in the occurrence in various types of vegetables