On November 5, 2024, Dr. Addie Waxman, North America Manager of Potato Storage at McCain Foods, presented a crucial webinar hosted by the North American Potato Storage Organization (NAPSO), focusing on the importance of the first 45 days of potato storage.
Dr, Waxman’s discussion emphasized the necessity of effective storage decisions to maintain quality and minimize losses. She initiated her presentation with a “Safety Moment,” highlighting the importance of safety resources and protocols in potato storage management.
She reinforced the need for a culture of safety among all personnel involved in handling and storing potatoes.
Make Storage Part of Your Winning Strategy!
Addie Waxman encouraged stakeholders to view storage as a critical component of their overall strategy for potato production.
“Growers have planted, grown, and harvested the crop,” she noted. “Let’s get those potatoes across the goal line with good storage decisions in the First 45 Days!” she said.
Dr. Waxman outlined several key objectives for potato storage, which are vital for maintaining product quality:
- Maintain Quality and Minimize Losses: Effective storage practices help preserve the physical and nutritional quality of potatoes.
- Minimize Carbohydrate and Respiration Loss: Strategies should be implemented to limit carbohydrate depletion and respiration losses.
- Humidity Management: Proper humidity levels are crucial to minimize evaporation loss while preventing condensation that can lead to disease.
- Oxygen and Carbon Dioxide Control: Ensuring adequate oxygen supply while removing excess carbon dioxide is essential for maintaining healthy storage conditions.
- Temperature Management: Maintaining a consistent desired temperature helps prevent deterioration and disease spread.
Other considerations include:
- Dry out wet potatoes
- Prevent disease spread/breakdown
- Maintain processing quality
- Avoid condensation
- Deal with suboptimal potatoes
Dr. Addie Waxman noted that storing potatoes for 9 to 12 months can provide a year-round supply, enhancing the monetary value of the crop.
“Storing potatoes long-term is a win for both packers/processors and growers,” she said. “Growers stand to make more money storing good quality potatoes,” she stated.
Storage Season Begins at Planting
Emphasizing the importance of long-term planning, Dr. Waxman remarked, “Storage season begins at planting!” She reminded attendees that conditions in the field directly affect the storage environment. “What happens in Vegas stays in Vegas,” she said. But in potato storage, “What happens in the fields follows you into storage, come what may….”
This highlights that the challenges and conditions faced during the growing and harvesting process have lasting implications for how potatoes are stored and managed.
Adapting Storage Strategies: Navigating Weather, Staffing, and Crop Placement
Addie Waxman underscored the fact that storage strategies are not static and can be significantly influenced by a variety of factors. Weather conditions play a pivotal role, as circumstances such as delayed or rushed harvests, as well as temperature extremes—whether hot or cold—can directly impact the condition of potatoes being stored.
Similarly, the moisture level during harvesting—wet versus dry—can introduce unique challenges. Staff availability and expertise also factor into effective storage management; being understaffed or lacking quality training can hinder the ability to respond to storage needs effectively.
Furthermore, crop placement is crucial; mismatched varieties, such as low-temperature storage (LTSR) potatoes placed with non-LTSR varieties, or a combination of early sprouting with late sprouting crops, can complicate storage dynamics.
Additionally, placing warm crops on top of cold ones, or mixing healthy and stressed crops can lead to uneven storage conditions, exacerbating the risk of spoilage and loss.
By adapting storage strategies to these variables, managers can optimize conditions and maintain the quality of stored potatoes.
Crop in Storage: Now What?
Once the crop is in storage, Addie Waxman provided guidance on the control features that managers should monitor, regardless of storage design:
- Temperature: Maintain optimal temperatures for the specific crop and variety.
- Relative Humidity: Striking the right balance of humidity is crucial; too much or too little can lead to quality issues.
- Carbon Dioxide Levels: High levels (>2500 ppm) can adversely affect potato quality.
- Airflow Management: Proper airflow is necessary to prevent both over-ventilation and under-ventilation, which can lead to different quality issues.
Decisions Affecting Shrink
Dr. Waxman highlighted how temperature and humidity management directly affect shrinkage in storage. Key points included:
- Over-Ventilation: This can lead to increased shrink and an unappealing appearance, reducing the volume available for processing.
- Under-Ventilation: Conversely, insufficient airflow can lead to a lack of oxygen and increased disease potential.
Delta T Airflow Management
Dr. Waxman also introduced Delta T (temperature differential) airflow management as an effective technique to optimize storage conditions. She explained how to assess the temperature differential:
- Take pulp temperature from the top of the pile.
- Take pulp temperature from the bottom of the pile.
- Calculate Delta T: Top temperature minus bottom temperature, in short. Subtract [Tt – Tb] = Delta T
Dr. Waxman further advised that an optimal Delta T should range between 1.0°F and 1.5°F (0.5°C to 0.75°C). If the differential is less than 1°F (0.5°C), it indicates over-ventilation, while a differential greater than 2°F (1°C) indicates under-ventilation.
She noted that for some piles and crate storages it’s hard to get readings, and storage managers may have to rely on sensors – although this might be an imperfect assessment, it is still better than no assessment at all.
Common Question Addressed
The most frequently asked ramping question Dr. Waxman gets in the field, is: “I brought my potatoes into storage cold. Should I warm them up to 55F for wound healing?”
Her personal/professional advice was clear, admitting that there are different opinions out there from others on this topic: “Do not heat up to 55°F for wound healing,” she recommends.
Instead, she said, ramp up to set point and hold there. Accept a delayed wound healing period. Keep in mind that microorganisms are slowed in growth at lower temperatures. Consider chemistries, if needed.
Crop Placement: Key Considerations for Optimal Storage
Effective crop placement is crucial for maintaining the quality and health of stored potatoes. Dr. Waxman emphasized the need to determine the optimal temperature for both ramping and final holding based on critical factors such as crop health, pulp temperature, and specific variety characteristics.
When managing a storage environment with both stressed and healthy crops, it is essential to recognize that the placement of these crops can significantly impact their condition. Stressed crops should ideally be positioned closer to the entrance for easier access and monitoring, allowing for quicker intervention when necessary.
Additionally, Dr. Addie Waxman addressed the challenges of storing mismatched varieties, specifically the differences between low-temperature storage (LTSR) and non-LTSR potatoes. The appropriate management of these varieties involves careful temperature setting; for instance, non-LTSR potatoes should be kept at their optimal set point of 48°F and unloaded promptly to avoid compromising quality.
Meanwhile, LTSR varieties, which can tolerate lower temperatures, should be gradually ramped down to a target temperature of 44°F to take advantage of their inherent traits.
The placement of warm crops on top of cooler ones can also lead to significant issues. Heat from the upper layers can create an unfavorable microclimate for the cooler potatoes below, increasing the risk of spoilage and disease.
By strategically managing crop placement and understanding the interactions between different varieties, storage managers can optimize the conditions in their facilities, ensuring the longevity and quality of their stored potatoes.
Stressed Raw Placement in Storage
In her discussion on optimal crop placement within storage, Dr. Waxman emphasized the importance of strategically managing stressed raw potatoes. She indicated that it is significantly easier to remove raw potatoes that are closer to the storage entrance, allowing for more efficient handling and minimizing potential losses.
Stressed raw potatoes, which may be bruised or damaged, pose a higher risk for disease development, making it crucial to monitor their condition closely.
Dr. Addie Waxman advised that storage managers should flag affected areas by the pipe locations, both at the top and bottom, to identify where airflow can be maximized to facilitate drying and reduce moisture accumulation.
Managing Crop Health and Variety Compatibility
She also highlighted the challenges posed by mismatched varieties in storage. For instance, non-low-temperature storage (non-LTSR) varieties should be placed in a manner that allows for quick removal when necessary. The ideal scenario involves setting non-LTSR varieties to their optimal temperature of 48°F and unloading them as soon as possible.
Meanwhile, remaining low-temperature storage (LTSR) varieties can be gradually ramped to a new target temperature of 44°F. This careful management not only preserves the quality of each variety but also maximizes the benefits associated with their unique storage capabilities.
In instances where early and late sprouting varieties are stored together, Dr. Waxman cautioned that the entire pile must be treated according to the weakest link. This means that early sprouting potatoes should be removed promptly to prevent them from affecting the overall quality of the late sprouting varieties.
By treating storage challenges with a tailored approach, managers can ensure that each type of potato retains its market value and quality for processing.
Addressing Temperature Variations
Temperature management is another critical aspect of potato storage that Dr. Waxman emphasized. Variations in harvest temperatures can create complications within the storage environment.
For example, if some potatoes are harvested at 65°F while others are at 48°F, airflow dynamics can lead to condensation zones, which can threaten the integrity of the stored crop. To mitigate these risks, Dr. Waxman recommended flagging the pipes that have potential condensation zones and implementing directed airflow strategies to manage the varying temperatures effectively.
Additionally, contacting chemical companies and notifying schedulers about any potential issues can enhance responsiveness to storage challenges.
Conclusion
Dr. Addie Waxman’s presentation during the NAPSO webinar provided essential insights into effective potato storage practices. By understanding crop conditions prior to storage, implementing best practices for airflow and temperature management, and addressing the unique challenges posed by various potato varieties, growers and storage managers can enhance the quality and profitability of their stored crops.
As the potato industry continues to advance, the strategies discussed in Dr. Waxman’s presentation serve as vital resources for professionals dedicated to optimizing potato storage practices. For more insights and resources, please visit the NAPSO website, where a comprehensive array of tools and information is available to support industry professionals.
Source: Dr. Addie Waxman, North America Manager of Potato Storage at McCain Foods
Contact:
[email protected]
Image: Dr. Addie Waxman. Picture supplied.
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