(Information provided by http://www.perishablelogisticsalliance.com/eng/history.asp)
In order for companies to transport their goods long distances without perishing, refrigerated transportation means were necessary.
It was by train and ship that most shipments requiring cool temperatures were transported in the late 1800s. Blocks of ice or frozen brine (as many as space would allow) were packed into railcars to help keep the freight cool. Of course, ice will eventually melt and so the train had to stop several times, depending on the distance of the destination, at icing stations along the way in order to load fresh ice. It was through this method that beef was able to be transported in 1857.
In 1868, the first refrigerated box car to use a salt-ice mixture to keep meat frozen was created by William Davis and sold to George Hammond.
The refrigerated box car continued to evolve in the next decade with Gustavus Swift creating an insulated car; however, ice was still needed to cool the freight within.
Finally in 1880, a mechanical refrigerated railcar came into light in the U.S. and in 1889, Florida oranges were finally able to be enjoyed by those in the northeast.
In the 1920s, mechanically refrigerated vans and trucks began to make their way into the light, with dairy companies being among the first customers (for example, ice cream maker Borden Company). The majority of these refrigerated vans/trucks were still kept cool using blocks of regular or dry ice, which weighed around 100-pounds each.
As in railroad transportation, drivers were able to replenish their ice at local truck stops. Since truck drivers stopped every 200-300 miles for new ice, it took longer for them to deliver a refrigerated shipment than it does today.
The number of refrigerated railcars continued to grow from around 50,000 in 1900 to ~183,000 in 1931.
30-35 foot van trailers were soon replaced with 38 to 40 foot semi-trailers in the late 1930s to haul more products at once.
Refrigerated tractor trailers, known as reefers, were soon appearing in great numbers throughout the country in the 1950s and continuing their growth through today.
Today’s reefers use “carbon dioxide as a cooling agent” and are “powered by small displacement diesel engines” (http://www.ehow.com/facts_5050431_reefer-truck.html#ixzz1KwBkY8at).
But technology has far surpassed the “blocks of ice” used in the past with companies such as Road Scholar Transport having ‘Thermal Mapped’ refrigerated trailers, which allow food and pharmaceutical companies to monitor their freight during transport.
Road Scholar Transport’s temperature protect service provides on-demand GPS location of your shipment, unlimited user-defined temperature alerts, online monitoring/reporting, as well as precise documentation of every time the door was opened/closed, the temperature at any given moment, and location at that time.