# A 15-Minute Exposure to Locally Available Disinfectants Eliminates Escherichia coli from Farm-Grown Lettuce While Preserving Quality in Ghana

## TL;DR

A 15-minute treatment with local disinfectants can safely remove E. coli from lettuce in Ghana without harming its quality.

## Contribution

A low-cost, practical method using locally available disinfectants to eliminate E. coli from lettuce while preserving quality.

## Key findings

- All three disinfectants eliminated E. coli from lettuce after 15 minutes.
- Sequential disinfectants preserved 100% structural integrity, while salt–vinegar caused 16% mushiness.
- Multi-drug-resistant E. coli isolates were common in both Accra and Tamale.

## Abstract

We evaluated the effectiveness of three locally available disinfectants in reducing Escherichia coli (E. coli) contamination of wastewater-irrigated lettuce while preserving structural integrity. We conducted a quasi-experimental study using lettuce from two farms (Accra and Tamale) in Ghana. Disinfectants tested included (i) salt combined with vinegar, (ii) sequential salt and potassium permanganate, and (iii) sequential vinegar and potassium permanganate. Structural integrity (stem crispness and leaf mushiness) was assessed at 5, 10, and 15 min. E. coli counts and antibiotic resistance were determined pre- and post-disinfection. All three disinfectants preserved structural integrity of lettuce at 5 and 10 min. At 15 min, sequential disinfectants preserved 100% structural integrity, while the salt–vinegar mix caused mushiness in 16%. Pre-disinfection E. coli counts were 9720 cfu/g for Accra (Inter Quartile range, IQR: 3915–14,175) and 72 cfu/g (IQR: 36–189) for Tamale. All disinfectants eliminated E. coli after 15 min. Multi-drug-resistant isolates were common (45% in Accra and 30% in Tamale), particularly against “Watch, restricted use” antibiotics. A 15 min exposure of lettuce to locally available disinfectants, particularly when used sequentially, can eliminate E. coli contamination while preserving structural quality. This practical, low-cost intervention can empower households, vendors, and farmers to limit lettuce-borne diarrheal diseases and antimicrobial resistance transmission.