Dennis Kihlstadius is the owner of consulting firm Produce Technical Services and widely regarded as an expert on post-harvest handling of climacteric fruit. He has taught the UC Davis Fruit Ripening & Ethylene Management Workshop for 23 years and has worked with commodity boards and companies around the world.
Consumers buy with their eyes and return with their taste buds. That’s why following the correct temperature and ripening protocols is essential for maximizing sales in many produce categories.
You may be familiar already with the details I lay out in the paragraphs below, or this may be new information for you. My goal is to educate on the conditions in which various produce items perform best so the industry can offer better, more consistent product and sell more.
I’ve long taught a workshop on fruit ripening at UC Davis, and I am the first to admit what happens in the research lab does not always translate to the real world. It has been my task over the years, working with many commodity associations and boards, to try and implement that knowledge from academia to operations in the real world of produce.
The one constant has been that age-old rule of transportation, storage and ripening: temperature, temperature, temperature.
All of those stages in the logistics channel must maintain the correct temperature, be it for food safety considerations or for the ability of the produce item to ripen and deliver a good eating experience.
Cold chain does not always mean cold; you probably would not accept your bananas at 56 degrees Fahrenheit or below pulp temperature before ripening them – unless you asked for “protection” from your supplier.
Following best practices in this area has revolutionized several categories over the years already. Take tomatoes, for instance.
Tomato transformation
When I started back in the late 80s, almost 85% of the tomatoes in the supply chain were below 50 degrees, which is the threshold of quality.
Below 55 degrees, two key things can happen in a tomato. They will get “mealy” inside, and the flavor enzymes are physically destroyed and never return. So you get a tomato that tastes like cardboard and has a poor “mouthfeel” for the end user. Not what you want when you are looking for a repeat sale.
Back in the day working for the California Tomato Board – it was a board before it was a commission – my “boss” was Ed Beckman, and the Florida Tomato Committee was run by Reggie Brown. Both Reggie and Ed wanted to have the tomatoes grown in California and Florida to have the best taste and shelf life that research could provide for the users of the tomatoes. It did not matter if it was a vine-ripe or a mature green tomato; both had a market and an end user for their attributes.
Once the tomatoes were put on a truck at the packing shed, we usually had no control over them, and everyone had their own temperature “recipe” for those tomatoes. You would not believe what they went through between the packing house to the end user, whether it was a foodservice operator or the consumer purchasing the tomato in a store. Re-packers and the end users were the key to helping me accomplish the goal of a good-tasting tomato.
The tomato industry achieved its temperature handling goals through education at many levels: consumer, trade publications, teaching events like the former Produce Academy held at the PMA Foodservice event. The research was clear, and the goal was to keep tomatoes above 50 degrees when fully ripe.
Bringing the science to the industry was the key to making this happen.
That effort included working with both the receivers, whether retail or foodservice, to change their incoming temperature specifications, and working with re-packers/ripeners to ensure proper ripening temperatures and shipping temperatures.
For many years, the supply chain failed the tomato because no one took seriously what the tomato needed to give a good eating experience.
Today, most everyone from foodservice to retail understands what temperatures you should keep a tomato at. The hothouse tomato industry has grown tremendously in size and prominence. They knew back then they had to have control over their product and demanded proper temperatures if you were going to have their product.
Temperature abuse that can create a mealy texture in a tomato can happen in stone fruit, too. Here’s the physics principle behind it: Water in its liquid form expands 3% in size from 50 degrees to 32 degrees. Have you ever forgotten a beverage can in your freezer? What happened?
Well, think of that same increase in size (3%) happening inside of your produce items. That expansion is what creates that mealy or mushy texture in a chill-damaged piece of produce.
The tomato industry is an example of how a category can be transformed when there is widespread commitment to proper temperature controls.
Bananas are another category for which norms are established and routinely followed, and consistent quality has served the category very well.
Financial implications
I understand logistics and storage is an imperfect world. However, I want everyone to understand that temperature abuse is the number one cause of shrink, disease, scoreable inspection disorders, and poor flavor and texture.
We are talking millions of dollars every year throughout the supply chain with all produce items. It is one of the factors we can actually control if we really want to. We have learned to store and ship bananas and tomatoes correctly over the years. What about the other temperature-sensitive produce items?
The industry as a whole and individual companies should consider this question: Can you afford to continue to treat the following produce items wrong?
- Mangoes – Don’t store below 50 degrees or 54 degrees, depending on the variety.
- Papaya – Don’t store below 50 degrees if you want it to de-green properly.
- Pineapples – Don’t store below 45 degrees.
- Limes – Don’t store below 50 degrees or you will get chilling injury – the brownish sunken area that looks like a continent on the surface.
There are other produce items that could go on this list, of course. The point is we need to pay attention to the produce items that need to be kept above 50 degrees. The best resource for information on proper temperatures by commodity is the Produce Facts section of the UC Davis Postharvest Technology Center.
Today’s consumers want their produce ready to eat, and if they have a poor eating experience, they go to social media to voice their complaints.
Here’s one final thought. Chilling injury occurs as a result of both time and temperature. There are PhDs studying this. My quick way for you to think about it is: You do more damage to a mango at 48 degrees in your warehouse for 2-3 days than by delivering it on a truck for 8-10 hours at 38 degrees.
If you are a retailer at store level and you put temperature-sensitive items in your cooler overnight – the cooler being 34-36 degrees – you are doing damage to them. Train your personnel to order those items daily or more regularly. Time in the backroom cooler destroys their shelf life and eating attributes.
Don’t get me started about the organics sitting on the reefer racks because someone thinks they will last longer from the refrigeration. That is wrong, and the customers of organics are paying more for those items usually. Refrigeration lowers the resistance and causes more disease issues for tropicals and other temperature-sensitive items.
It is time to change the design of stores to where we have two temperature reefers in the backrooms, and the backrooms also need to be larger to provide space for the produce that should not be put in the cold box if you are not going to have a 50-55-degree cooler.
The opportunity for better tasting fruit is out there, and temperature is key.
Making necessary changes across the supply chain to support that goal will take some time and resources, but based on what we’ve seen with the tomato and banana categories over the years, it is a worthwhile investment.