Evaporated and condensed milk are two types of concentrated milk from which the water has been removed. Evaporated milk is milk concentrated to one-half or less its original bulk by evaporation under high pressures and temperatures, without the addition of sugar, and usually contains a specified amount of milk fat and solids. This gives regular evaporated milk—the shelf life differs with the fat content—up to 15 months of shelf life. Condensed milk is essentially evaporated milk with sugar added. The milk is then canned for consumer consumption and commercial use in baking, ice cream processing, and candy manufacture. This product has a shelf life of two years. When concentrated milk was first developed in the mid-1800s before the advent of refrigeration, many used it as a beverage. However, with the exception of some tropic regions, this is rarely the case today.

Question

In 1852, a young dairy farmer named Gail Borden was on a ship headed home to the United States from the Great Exhibition in London. When rough seas made the cows on board so seasick that they could not be milked, infant passengers began to go hungry. Borden wondered how milk could be processed and packaged so that it would not go bad. This was a problem not only on long ocean voyages but on land, as well, because at the time, milk was shipped in unsanitary oak barrels and spoiled quickly.
When Borden returned home, he began to experiment with raw milk, determining that it was 87% water. By boiling the water off the top of the milk in an airtight pan, Borden eventually obtained a condensed milk that resisted spoilage. On another trip, this time by train to Washington, DC, to apply for a patent for his new product, Borden met Jeremiah Milbank, a wealthy grocery whole-saler. Milbank was impressed with Borden's ideas and agreed to finance a condensed milk operation. In 1864, the first Eagle Brand Consolidated Milk production plant opened on the east branch of the Croton River in southeastern New York.
The outbreak of the Civil War proved to be good for business when the Union Army ordered the condensed milk for its field rations. At the height of the war, Borden's Elgin, Illinois plant was annually producing 300,000 gallons of condensed milk.

Q1 - What are the important processes that address bacterial growth issues which allow these products to store for a long time?

Q2 - Explain how these products are sustainable?

Answer 1

Q1 - Important Processes Addressing Bacterial Growth for Long Shelf Life

1. Evaporation:

   • Both evaporated and condensed milk undergo a process of evaporation where water content is significantly reduced. This reduction in moisture creates an environment that is less hospitable for bacteria and other microorganisms, thereby reducing the potential for spoilage.

2. Heat Treatment:

   • The milk is subjected to high temperatures during the evaporation process. This heat treatment not only helps in concentrating the milk but also kills many harmful bacteria and pathogens present in the raw milk, further enhancing its shelf life.

3. Airtight Packaging:

   • The concentrated milk products are packaged in airtight containers, which helps prevent the entry of air, light, and moisture. This minimizes the risk of contamination and spoilage from the environment.

4. Addition of Sugar (Condensed Milk):

   • In the case of condensed milk, sugar is added during processing. The high sugar content acts as a preservative, inhibiting microbial growth due to osmosis, where the sugar draws moisture away from microorganisms, thus preventing their proliferation.

5. Acidification (Optional for Some Products):

   • Although not typically used in evaporated or condensed milk, acidification can be another method for extending shelf life by lowering the pH, making the environment less favorable for bacterial growth.

Q2 - Sustainability of Evaporated and Condensed Milk Products

1. Reduced Waste:

   • The long shelf life of evaporated and condensed milk reduces food waste, as consumers have more time to consume the products before they spoil. This is particularly important in regions where refrigeration and proper storage facilities are limited.

2. Efficient Use of Resources:

   • Concentrating milk allows for more efficient transportation and storage. Transporting concentrated milk is less resource-intensive than transporting fresh milk, as less volume translates to lower carbon emissions from transportation.

3. Extended Seasonal Availability:

   • The production of concentrated milk allows it to be available year-round, regardless of the season or conditions affecting fresh milk production. This consistent availability makes dairy products more accessible, especially in areas with challenging climates.

4. Support for Local Dairy Farmers:

   • The production of evaporated and condensed milk creates a market for local dairy farmers, providing them with steady income. This can encourage more sustainable farming practices and support local economies.

5. Recycling and Packaging Practices:

   • Many manufacturers are shifting toward sustainable practices in packaging, including recyclable or biodegradable materials. Innovations in packaging can also help reduce waste and the environmental impact of dairy products.

6. Less Dependence on Cold Chain Logistics:

   • Since these concentrated milk products do not require refrigeration until opened, they lessen the dependency on cold chain logistics, which can be a significant energy consumer. This can lead to a more sustainable supply chain.

7. Potential for By-product Usage:

   • The process of making concentrated milk can result in by-products that may be used for other purposes, such as feeding livestock, thus maximizing resource utilization.

Overall, the production and consumption of evaporated and condensed milk can contribute to more sustainable food systems by reducing waste, improving resource efficiency, and supporting local agriculture.