Business and public health impacts of food safety upgrading among pork vendors in Vietnam

Training of pork vendors in traditional wet markets; enrollment of interested vendors in a voluntary food safety grading program; promotion of the grading program to consumers in these markets.

All vendors in treatment markets (including vendors not selected to participate in the study) will be invited to a training session in which they are given instruction on good food hygiene practices. At the training, 50% of study vendors in the market (up to five vendors) will be drawn for assignment to the ‘training + subsidy’ (T2) sub-treatment. In addition to training, T2 vendors will also receive free supplies (e.g., easy to clean surfaces, bleach, handwashing stations) to facilitate the practices on which they have been trained. The remaining 50% of vendors (up to 5) in each T market will be assigned to receive ‘training only’ (hereafter referred to as T1). Provision of free materials to a subset of vendors is intended to induce experimental variation in food ratings within T markets.
Vendors who have completed training will be given an opportunity to enroll in a voluntary food safety grading program. Within two weeks of the training session, a surveillance team employed through the study will visit each of the vendors enrolled in the program to observe their food safety practices. Vendors will not be informed of surveillance visits ahead of time, and surveillance officers will not initially identify themselves to vendors, so that vendors' routine practices can be observed. Vendors will be assigned a food safety grade based on the observations of the surveillance team and given signage indicating this grade. After the initial surveillance round, each treatment market will receive one to two randomly timed surveillance visits per month, during which a team of two surveillance officers will each visit two randomly selected vendors (with replacement each month) simultaneously. Vendors’ safety ratings will be updated according to the results.

2023-10-23

2024-05-15

Total bacteria count (logCFU/g)
Salmonella (presence/absence)

Index of hygiene practices
Consumers choose vendor based on food safety
Expenditure of vendors on food-safety related inputs
Value of pork sales per hour (as a correlate of hygiene practice index in T vs. C markets)

Consumers' stated reason for selecting vendor is one of: food safety, cleanliness, or high food safety rating
Value of pork sales per hour: natural logarithm of the value of pork sales per hour, based on reported purchase amount at the start of the day, time of the end-of-day vendor interview, and observed pork remaining at the end-of-day interview
Index of hygiene practices: standardized inverse-covariance weighted average (Anderson, 2008)

68 pork markets will be randomized to Treatment or Control status. 10 vendors will be enrolled in the study in each Treatment market, 5 vendors will be enrolled in each Control market. A baseline survey will be conducted in each market. Intervention activities will commence in Treatment markets within a week of the baseline survey. Surveillance visits and updating of food safety grades will continue for 3 months. Follow-up data collection will be conducted approximately 3 months after baseline data collection. A second follow-up round of data collection may be conducted after an additional 3 months, subject to funding availability.

Market-level treatment assignment: in office by a computer
Vendor-level treatment assignment: via public drawing in Treatment markets, at the end of the training session

Market (for training and offer of enrollment in food safety grading program)
Vendor (for provision of equipment, within Treatment markets)

Yes

68 markets

510 vendors up to 1020 consumers (15 per market)

34 markets Treatment, 34 markets Control
170 vendors T1, 170 vendors T2, 170 vendors Control
510 consumers Treatment, 510 Consumers Control

analysis plan