Microbiological quality of Lactuca sativa (lettuce) salad vegetables sold in restaurants in Kigali, Rwanda

Abstract

Background: Salad which is served at restaurants in uncooked form can be source of bacterial contamination.

Aim: To assess the microbiological quality of lettuce (Lactuca sativa) salads sold in two restaurants in Kigali, Rwanda.

Methods: Lettuce samples were collected using aseptic techniques and immediately analysed using standard media for E. coli, Salmonella, Shigella and Staphyloccocus aureus besides total aerobic count.

Results: The number of total aerobic bacteria ranged from 1.15 x10⁴ to 2.87x10⁴ cfu/ml for restaurant 1 and from 1.91x10⁴ to 2.13x10⁵cfu/ml for restaurant 2. Staphyloccoci count ranged from 3.6x10² to 1.173x10³ cfu/ml for restaurant 1 and from 1.9 x10² to 3.2 x10² cfu/ml for restaurant 2. Gram negative bacteria count ranged from 8.3 x10² to 1.03 x10⁵ cfu/ml for restaurant 1 and from 5.05 x10² to 2.30 x10⁵ cfu/ml for restaurant 2. Salmonella and Shigella count ranged from 2.54x10³ to 2.04x10⁴ cfu/ml for restaurant 1 and from 3.65x10³ to 2.5x10⁴ cfu/ml for restaurant 2. E. coli was found in 75% of the sample from restaurant 1 and 100% of the sample from restaurant 2.

Conclusion: Improvement in hygiene is needed during preparation and handling of lettuce salad in these restaurants.

Keywords: Lactuca sativa, microbiological quality, restaurants, Rwanda