Post-harvest is a critical phase of agriculture. Optimised handling and processing of crops ensure the best quality of the product, increasing its value, and minimising waste.
In a recent live session of Food For Mzansi’s Gather to Grow, experts explored the nuances of different handling techniques, the importance of understanding your crops, and the technical aspects of packaging materials.
Neo Hlongwane, a researcher and quality controller at Barenbrug Seed SA, and Tapiwa Masimba, a production manager, provided tips on best practices in handling and processing harvested crops to minimise damage, contamination, and spoilage, which include sorting, cleaning, and packaging procedures.
Importance of crop knowledge
Hlongwane encouraged farmers to understand their crops, recognising what a healthy crop looks like to identify issues early on.
“You must know how your crop looks when it is healthy or when it is good for humans or animals to consume and then after that, after knowing what a healthy crop looks like, you can tell when there is something on your field that doesn’t look good,” he said.
Masimba shared that different crops require distinct handling techniques to prevent damage, giving the example of tomatoes compared to potatoes. In addition to this, he discussed the different temperatures required for storage and transportation with crop species. Methods of sorting crops are also essential to ensure quality and uniformity.
Removing contaminants
Masimba shared that contaminants vary from soil to insects. Initial cleaning begins in the field and continues through mechanised washing and sorting processes in packing facilities.
“The process already starts from the one who is harvesting in the field. Whatever they can visually see while harvesting, they should, if they can, take it out if it’s a leaf which is maybe diseased or something like that. The people harvesting already start the process of removing contaminants.
“Then when it goes to the pack house, the final process [is] where the people are now taking everything into detail,” he said.
Hlongwane comments that packaging must consider shelf life, transportation, and market presentation.
“The shelf life matters the most because you can’t just take a product to a store and within a week it is already spoiled. That is something that is not acceptable, so I think making sure that the product that you are using is up to standard,” he shared.
Masimba added that techniques such as specific perforations in packaging and using nitrogen to stabilise products are employed to maintain quality. He noted that crops are graded based on size and quality and that customer specifications can significantly impact handling and presentation.
Temperature, humidity, and moisture control
Hlongwane discussed that temperature control is essential for reducing natural senescence of crops after harvest. It helps slow down the process until the product reaches the end user.
“All the crops have a specific temperature, moisture content, and relative humidity they can thrive in because too much or too little, your product is going to spoil or the quality is going to degrade,” he said.
Masimba added that suitable temperature ranges can prevent pathogen growth, thereby extending shelf life. Consistency in temperature is crucial from field to end user to avoid reducing shelf life.
“The biggest factor is don’t let it fluctuate, because the moment it fluctuates, in most cases, you also lower the shelf life of your product. Whatever temperature you put on the product, just maintain it until it gets to the end user.”
Masimba shared that there are methods to compensate for fluctuations and stabilise temperature, like the use of nitrogen gas.
He noted that technology helps in detecting issues that are not easily visible to the naked eye. It is useful in processes such as automation in packing, shredding, sealing, and improves efficiency. “The ultimate goal is to feed the population quickly, efficiently, and affordably.”
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