Delighted that Our Paper on Fresh Produce Trade and "Choke Points" is Published in EJOR!

The three of us worked very hard on this paper, "Fresh Produce Spatial Price Equilibrium on General Networks: Capturing Commodity Quality Deterioration Through Endogenous Transportation Time Delay Functions with Capacities," and it took three revisions (a record for me, I must say) before acceptance. My co-authors on this paper are Samirasadat "Samira" Samadi, who is one of my PhD students, and Professor Deniz Besik of the Robins School of Business at the University of Richmond.

The paper was published in a volume of the European Journal of Operational Research (EJOR) this past week, which was extra exciting since it also was the last week of classes of the academic year at UMass Amherst!

The link to the journal publication of the article is here: https://www.sciencedirect.com/science/article/abs/pii/S0377221726003759.

The work was inspired by many challenges associated with fresh produce transportation and quality of the commodities because of issues such as drought as in the Panama Canal and now the essential shutdown of the Strait of Hormuz because of the war on Iran. We capture endogeneous transportation delays due to capacity reduction on links and the impact on quality of fresh produce as it travels from supply markets to demand markets. The case study in the paper is on the global trade of bananas, a nutritious and very popular fruit, which is also important for food security. We also propose commodity quality trade network performance measures, supply-based, demand-based, and network-based, that can be applied for an individual commodity or across all commodities.

We are grateful to the EJOR Editor, Professor Mike Yearworth, who handled out paper, and to the reviewers for their comments and suggestions. My co-authors and I very much believe in the relevance and importance of the research that resulted in this paper.

Our Latest Paper on Multicommodity Trade of Fresh Produce with a Case Study on Bananas Is Now Published!

I am thrilled that the paper, "Multicommodity Fresh Produce Trade Networks with Quality Deterioration Under Congestion and Transportation Capacities," that I co-authored with Deniz Besik of the University of Richmond is now published in the Journal of Global Optimization! Plus, the paper is published open access and can be read and downloaded on the link: https://link.springer.com/article/10.1007/s10898-025-01507-3.

Deniz presented this paper last year at the EURO Conference in Copenhagen:

The paper contains a very interesting case study on bananas, the most widely traded fruit globally, and demonstrates the impacts on fresh produce quality of transportation disruptions and delays. The work was inspired by recent challenges to transportation on the Panama Canal because of insufficient water, leading to congestion. The paper shows that because of negative transportation impacts, consumers may pay higher prices for bananas of lower quality. 

Deniz will present this paper at the 2025 Commodity and Energy Markets Association Annual Meeting (CEMA) in Houston in a few days, as I head to the EURO Conference in Leeds, United Kingdom, where I have three invited talks!

This was another outstanding collaboration of ours on a highly relevant topic.

My Upcoming INFORMS Webinar: Blood, Sweat, and PPEs

The invitation came from Dr. Patricia Neri, who serves on the Board of the Practice Section of INFORMS. Would I be interested in giving the inaugural webinar in their Practice Series? Very quickly I agreed. There was specific interest in having me speak on perishable product supply chains in the Covid-19 pandemic. I have had multiple interviews in the media on this topic (radio, TV, and print) and it was an opportune venue in which to synthesize thoughts as well as earlier and recent research on supply chains and disruptions.

I have been working on the presentation slides for my webinar, which is entitled, "Blood, Sweat, and PPEs: Rescuing Perishable Product Supply Chains and Impacting Policy Through Analytics." The webinar will take place on June 12, 2020, with Q&A to follow. The webinar is open to the public and information on registration is available here. Joining me on the Q&A panel will be Dr. Patricia Neri and Dr. Carrie Beam (I thoroughly enjoyed brainstorming with both recently on the title!). Special thanks also to Beth West of INFORMS for handing the logistics for my webinar.

The World Health Organization declared the Covid-19 global epidemics an official pandemic on March 11, 2020, and, even before then, I was hard at work conducting research on disruptions to supply chains because of the coronavirus. On March 12, 2020, my article on the stressed blood supply chain and the coronavirus was published in The Conversation. To this date, the article remains the most read article by a UMass Amherst faculty member, published in the outlet over the past year. It was followed by an invited piece in the INFORMS Analytics Coronavirus Chronicles.

Perishable product supply chains, including a variety of food ones, PPEs (which are time-sensitive), a well as blood supply chains, are some of the supply chain networks that have been most severely impacted in the pandemic. In this webinar, I will discuss our earlier work and present research on such topics and, for the latter, I will emphasize new work that includes the inclusion of labor under different constraints in supply chains. I will also highlight a recent paper on convalescent plasma that I wrote with Dr. Pritha Dutta on what has become a unique market consisting of competition among nonprofits and profit organizations for plasma from Covid-19 survivors for therapies in those suffering from the coronavirus. Finally, I will describe how work in operations research and analytics is influencing policy on a national level in a significant way.

And, since several of you have asked, below, I have highlighted some of the recent media interviews that I have taken part in, which are accessible on the links below. Many thanks for the interest! Hope that you can join me for the webinar.

Interview by UMass Amherst

Article on the Isenberg School Website on Impact on Policy

NBC Boston TV News Interview on Meat Shortages

Radio Interview on Farm Talk

Diaper and Wipe Shortage Radio Interview - Los Angeles

Interview for The Verge on Algorithms in the Pandemic and Supply Chains

Interview in USA Today on Diaper and Wipe Shortages

Interview in Morning Consult on Collateral Damage in the Pandemic

Also, many thanks to the American Mathematical Society and to Mike Breen for hosting me on the podcast on supply chains and Covid-19.

Game Theory and Fresh Produce Supply Chains - It's About the Fruits and Veggies

Is there anything more delicious than a ripe peach or mango? Or, perhaps, you love biting into a sweet, crisp apple? I love my fresh fruit and veggies and, frankly, we are spoiled, in a sense, in the US, where we can savor berries and cherries even in the winter. You probably also enjoy a variety of vegetables and I am not speaking of just French fries.

At the same time, when the "fresh" produce is not so fresh, one gets quite disappointed and the wastage associated with this industry is vast. Quality of fruits and vegetables is a topic, hence, of great research and practical interest and not only for food scientists and economists,  but operations researchers as well.

The first paper that my group published on fresh produce supply chains was: Competitive Food Supply Chain Networks with Application to Fresh Produce, Min Yu and Anna Nagurney, European Journal of Operational Research 224(2): (2013) pp 273-282, a paper that is highly cited and was even recognized by the Editors of the journal in a special session last July at the fabulous EURO conference in Poznan, Poland. You can read my blogpost, which even has photos of delicious pierogies here.

In this paper, we utilized game theory to capture competition among food firms, who differentiate their products, which are perishable, and we applied the model to a case study of cantaloupes, subject also to a disruption. Indeed, there have been some major quality issues resulting in food-borne illnesses in this sector. Quality in this paper was modeled using a generalized network framework with link multipliers and it was assumed that as the fresh produce "moved" over links in the supply chain that a certain percentage would "perish" and would, hence, be discarded.

More recently, we turned to short fresh produce supply chains in the form of farmers' markets.  In the paper, Quality in Competitive Fresh Produce Supply Chains with Application to Farmers’ Markets,
Deniz Besik and Anna Nagurney, which is now in press in Socio-Economic Planning Sciences, we used kinetic formulae to model quality deterioration over time and under temperature conditions. I think that this is super cool and very much enjoy bringing scientific disciplines from chemistry to physics to operations research supply chain modeling.  We then applied the model to apple farms in western Massachusetts, and, since one of the farms was Apex Orchards (one of my favorites), below I have photos of their relatively new store in Shelburne Falls.

And I can't resist sharing the photo below of the bridge of flowers in neighboring Shelburne.

In Amherst, we have a farmers' market from May through October in downtown, which is very enjoyable and also highly social. The Farmers' Market then moves indoors for the winter and whenever we are in town we always visit and purchase produce. You know where it is coming from and when it was picked. Our paper we dedicated to Robert Colnes, who owned an orchard in New Salem and who was a fellow Brown University alumnus. Deniz had interviewed him multiple times. He passed away a few months ago at age 96 and before we could share with him the good news that our paper had been accepted for publication. He was so generous in answering questions.

Last spring/summer I spent several months as a Visiting Fellow at All Souls College at Oxford University (a simply heavenly intellectual and aesthetic experience that will be very hard to top). While at Oxford I would regularly go to the Farmers' Market in the center of Oxford and the photos below capture some of the spirit of it.

The food stalls at the Oxford Farmers' Market are fabulous and there is a wide variety of ethnic cuisines for purchase.


In the paper, Supply Chain Network Capacity Competition with Outsourcing: A Variational Equilibrium Framework, Anna Nagurney, Min Yu, and Deniz Besik, in press in the Journal of Global Optimization, we used game theory, but the governing equilibrium concept was a Generalized Nash Equilibrium (rather than a Nash Equilibrium as in the above papers), since the producers' constraints, and not just their utility functions, depended on the strategies of the other producers.  The case study was to apples in western Massachusetts. We used variational equilibrium to formulate the problem.

What I find so special about the discipline of Operations Research is that you can work on what you love and that includes food supply chains!

Food Supply Chains -- Competing on Freshness and Price

I have recently returned from two weeks in Sweden and I miss Sweden  already.

I  even miss the food, which was fabulous and tasted better than that in the US. I enjoyed the meals in the cafeteria at the School of Business, Economics and Law at Gothenburg University, where I sampled several lunches (and sneaked down for some dark chocolate as well) and the food in the cafes, bakeries, and the restaurants. During the two week period I dined on Swedish, Turkish, Italian, Indian, French, and even Polish cuisine.From my colleagues I learned about the big fresh produce auctions in Amsterdam but that bananas get shipped directly to Sweden.

Just before traveling to Sweden in mid-March, my doctoral student, Min Yu, and I finished the paper, "Competitive Food Supply Chain Networks with Application to Fresh Produce."  In the paper, we model the deterioration of fresh produce over time and under different storage and transportation conditions. In the network model, we also capture the discarding costs associated with the disposal of the spoiled food products and allow for product differentiation.

We utilize variational inequality theory to formulate the game theoretic problem in which the firms compete until a Nash equilibrium is attached.

 A case study in our paper focuses on the cantaloupe market, in which we analyze different scenarios prior to, during, and post a foodborne disease outbreak.