Lettuce: Predicting high risk plantings to manage postharvest pinking


FV 413a - Lettuce: Predicting high risk plantings to manage postharvest pinking

Start Date: 
Completion Date: 
Project Leader: 
Dr Jim Monaghan, Harper Adams University
FV 413a

Industry representative: Emma Garrod

HDC project cost: £125, 455


The Problem:

Following harvest some lettuce can produce pink colouring in the butt and ribs of the outer leaves. This is termed Pinking and, in spite of the development of new varieties with claims of reduced pinking, continues to present substantial problems for producers with both UK and imported crops. Poor product on the shelf reduces sales and leads to more complaints and consumer dissatisfaction. A recent review of research into lettuce pinking (FV 413) identified that issues such as high rainfall/over irrigation have a direct influence on expression of pinking. This project aims to establish the environmental conditions and timings that correlate with pinking in harvested heads of Iceberg and Cos lettuce. Guidelines for identifying high-risk crops will be developed based on local meteorological and crop input records enabling growers to manage crops through the supply chain to the benefit of the customer.
The mycotoxin research has been successfully implemented by the cereal industry with the generation of Guidelines and Codes of Practices to minimise risk and a HGCA mycotoxin risk assessment scheme where growers input agronomic factors and rainfall data to predict a low, moderate of high risk of exceeding legal limits of fusarium mycotoxins. This has led to growers clearly understanding the risk factors and modifying their agronomy accordingly.


Benefits to industry
Pinking losses are hard to quantify, but can account for substantial customer complaints at certain times of the year and batch rejections. The importance of the work to the industry can be gauged from the willingness of seven businesses to provide crop samples for the study.
• Anglia Salads – Essex
• Jepco – Lincolnshire
• G’s – Norfolk/Cambridgeshire/W. Sussex
• PDM – Shropshire
• Huntapac – Lancashire
• Kettle – Fife
• Intercrop - Kent
These businesses account for the great majority of UK wholehead lettuce production.
The results of the investigation will be available to the industry through the final report, HDC website, HDC news and presentation to the BLSA and other grower groups as appropriate.
It is anticipated that no additional resources would be necessary for growers to use the guidelines or simple model developed in the work. The project will provide information to help QC teams fulfil their current responsibilities.
Aims and objectives:
Project aim(s):
To investigate preharvest environmental factors that influence postharvest pinking in lettuce
Project objective(s):
• Identify the key preharvest environmental conditions and timings that correlate with postharvest pinking in Cos and Iceberg lettuce
• Produce guidelines for identifying Cos and Iceberg crops at risk of postharvest pinking