Condensed milk
Condensed milk, commonly referring to sweetened condensed milk (while "condensed milk" can also refer to unsweetened evaporated milk), is a thick, preserved dairy product obtained by partially removing water from a mixture of cow's milk and nutritive carbohydrate sweeteners, such as sugar. It must contain at least 8% milkfat by weight and 28% total milk solids by weight, with the added sweeteners serving to inhibit spoilage by creating an environment unsuitable for microbial growth.[1] The product is typically pasteurized and may be homogenized for uniformity, and it is shelf-stable when unopened due to its high sugar content, which acts as a natural preservative.[1] Invented by American inventor Gail Borden Jr. in 1856 through a vacuum evaporation process that removed water while preventing contamination by airborne impurities, sweetened condensed milk provided the first reliable method to preserve milk without refrigeration, significantly improving access to safe dairy nutrition in the 19th century.[2] Borden's innovation, patented as U.S. Patent No. 15,553, gained widespread adoption during the American Civil War when the Union Army used it to supply troops, transforming the dairy industry from localized production to large-scale manufacturing and distribution.[2] Today, it remains a staple in global food production, particularly in regions with limited refrigeration. In the food industry, sweetened condensed milk is prized for its rich texture and sweetness, serving as a key ingredient in confectionery items like toffees and fudges, where interactions between milk proteins (casein) and sugars contribute to desirable viscoelastic properties.[3] It offers a nutrient-dense option especially valuable for vulnerable populations like athletes or those in challenging conditions such as during conflicts or disasters.[4] Beyond these applications, it enhances baked goods, desserts, and sauces, providing both flavor and structural benefits due to its concentrated composition of 8–9% fat and 43–45% sucrose.[5]Overview and Types
Definition and Composition
Condensed milk is a dairy product derived from cow's milk by partially removing water through evaporation, resulting in a thick, concentrated liquid. It encompasses two primary varieties: sweetened condensed milk, which includes added nutritive carbohydrate sweeteners such as sugar to enhance preservation and flavor, and unsweetened condensed milk, commonly known as evaporated milk, which relies on concentration and sterilization for stability without added sugars. This process typically removes approximately 60% of the water content from fresh milk, concentrating the natural components while maintaining the whey protein to casein ratio unless adjusted with milk constituents.[6][1][7] The basic composition of condensed milk varies between its sweetened and unsweetened forms. Evaporated milk typically features about 74% water content, with the remainder consisting of milkfat, proteins, and lactose. It must contain at least 6.5% milkfat and 23% total milk solids by weight, including a minimum of 16.5% milk solids-not-fat, providing a rich profile of approximately 7-9% fat, 7-9% protein, and 10-12% lactose. Sweetened condensed milk has about 27% water content, requiring a minimum of 8% milkfat and 28% total milk solids, with typical formulations including 8-10% milkfat, 8-10% protein, 40-45% added sugar, and the balance as concentrated milk components, which collectively lower the water activity to inhibit microbial growth. These proportions ensure a nutrient-dense product that retains essential dairy elements like casein and whey proteins in heightened concentrations compared to fresh milk.[7][1][8][9][10] Physically, evaporated milk exhibits a viscous, creamy, pourable texture attributable to the evaporation process, which increases the density and intermolecular interactions among proteins and fats. Sweetened condensed milk, in contrast, has a thicker, syrupy texture due to the added sugars. When canned, evaporated milk is preserved through heat sterilization, achieving extended shelf stability lasting up to two years unopened, while sweetened condensed milk is preserved by the high sugar content and can remain stable indefinitely at room temperature without further sterilization. However, upon prolonged heating, such as in culinary applications, sweetened condensed milk is particularly prone to caramelization through Maillard reactions and sugar browning, producing a golden color and enhanced flavor but potentially leading to thickening or crystallization if overheated.[11][12][13][12] Legal standardization ensures consistency and safety, with regulatory bodies like the U.S. Food and Drug Administration (FDA) defining minimum solids and fat levels for proper labeling as condensed or evaporated milk, preventing misbranding and guaranteeing quality. For instance, FDA regulations under 21 CFR 131.120 and 131.130 mandate specific compositional thresholds and pasteurization to meet these standards, while international guidelines from the Codex Alimentarius provide similar minima, such as 7.5% milkfat and 25% total solids for evaporated milk equivalents. These definitions prohibit the addition of non-milk fats or excessive fillers, preserving the product's integrity as a concentrated dairy form.[1][7][14]Sweetened vs. Evaporated Milk
Sweetened condensed milk and evaporated milk represent the two main variants of condensed milk products, both derived from fresh cow's milk with approximately 60% of the water removed to achieve concentration. Sweetened condensed milk is produced by evaporating whole milk under vacuum to preserve flavor, followed by the addition of sugar at 40-45% by weight, which not only imparts sweetness but also serves as a primary preservative by creating a high-sugar environment that inhibits microbial growth.[15] In contrast, evaporated milk is unsweetened, involving the partial removal of water from milk to create a double concentration, after which it is homogenized to ensure even fat distribution and then subjected to heat sterilization in sealed cans to eliminate pathogens and extend shelf life.[16] The key differences between these products lie in their composition and preservation methods, which directly influence their uses and longevity. Sweetened condensed milk contains about 28.5% total milk solids, 8.5% milk fat, and 42% sugar, resulting in a thick, syrupy texture ideal for sweet applications like desserts and beverages where added sweetness is desired. Evaporated milk, however, adheres to standards of at least 6.5% milk fat and 16.5% total milk solids with no added sugars, providing a neutral, creamy profile suitable for versatile savory or general cooking purposes, such as in soups, sauces, or as a fresh milk substitute when diluted. Regarding shelf life, unopened sweetened condensed milk can remain stable indefinitely at room temperature due to the preservative effect of sugar, requiring no post-sealing sterilization, whereas unopened evaporated milk typically lasts 1-2 years under similar conditions, thanks to the sterilization process, though flavor may degrade after six months.[17][18][19] Regional naming conventions can add confusion to these distinctions. In the United States, "condensed milk" commonly refers specifically to the sweetened variety, while "evaporated milk" denotes the unsweetened type; however, in some other countries, evaporated milk is known as "unsweetened condensed milk," leading to potential mix-ups in international contexts.[15][20]History
Invention and Early Development
Early methods of milk preservation date back to ancient civilizations, where boiling milk to reduce its water content was practiced in regions such as India to create khoya, a concentrated dairy product formed through thermal desiccation at atmospheric pressure.[21] Similar techniques involving boiling and concentration were employed in the Middle East for producing thickened milk products, though these were primarily for local consumption and lacked the scalability of later innovations.[22] Modern condensed milk, however, emerged in 19th-century Europe through pre-commercial experiments aimed at longer-term preservation. In France, Nicolas Appert conducted pioneering work on food preservation in the early 1800s, developing a canning method that included sealing heated dairy products, such as milk, in airtight glass containers to prevent spoilage; he received official recognition for this process in 1810.[23] Appert's approach focused on thermal processing rather than evaporation, but it laid groundwork for vacuum-based techniques by demonstrating the viability of sealed preservation for liquids like milk.[24] The development of condensed milk as a distinct product is credited to American inventor Gail Borden Jr., who was motivated by the rapid spoilage of fresh milk during long sea voyages, particularly after witnessing infants fall ill on a return trip from England in 1851 due to contaminated or unavailable supplies.[25] Borden sought to create a stable alternative by evaporating milk under vacuum to remove water while retaining nutrients, applying for a U.S. patent on this process in 1853; the patent was initially rejected for lack of novelty but granted in 1856 as U.S. Patent No. 15,553 after refinements, including the addition of sugar to inhibit bacterial growth.[26] Early prototypes faced significant challenges, as unsealed or insufficiently sweetened batches remained prone to spoilage despite vacuum evaporation.[27] Borden's breakthrough came with a successful 1856 trial shipment of his sweetened condensed milk aboard a ship to England, where it arrived unspoiled and demonstrated the method's potential for safe transport over extended periods.[28] This experiment validated the vacuum evaporation technique for preserving milk's quality during maritime journeys, addressing a critical need in an era without widespread refrigeration.[29]Commercialization and Global Spread
Gail Borden founded the New York Condensed Milk Company in 1857, marking the beginning of commercial production of condensed milk in the United States. The company's first factory opened in Wassaic, New York, in 1861, enabling large-scale manufacturing. Sales experienced a significant boom during the U.S. Civil War (1861–1865), as the Union Army contracted for vast quantities of condensed milk as a portable and non-perishable ration for soldiers, with demand exceeding the factory's initial output capacity.[30][2] In 1866, the Anglo-Swiss Condensed Milk Company established Europe's first condensed milk factory in Cham, Switzerland, founded by American brothers George and Charles Page. In 1867, pharmacist Henri Nestlé developed an infant formula known as Farine Lactée, made from cow's milk, wheat flour, and sugar, which he began marketing as a nutritious alternative for babies unable to be breastfed. By the early 1870s, Nestlé had launched its own production of condensed milk, positioning the company as a direct competitor to Anglo-Swiss, and expanded sales across Europe, including to the United Kingdom and German Empire, while entering the U.S. market through exports and partnerships.[31][32] The global spread of condensed milk accelerated in the late 19th and early 20th centuries, particularly through colonial trade routes. In Asia, it was introduced during American colonization of the Philippines following the Spanish-American War in 1898, where canned condensed milk became a staple import for U.S. military personnel and colonial elites, eventually integrating into local cuisine despite initial hygiene concerns about native foods. By the 1900s, production peaked in major markets, with companies like Borden and Nestlé establishing factories and brands in East Asia, capturing significant shares through targeted advertising. During World War I and II, demand surged globally as militaries relied on condensed milk for its shelf stability and caloric density in rations, further embedding it in supply chains worldwide.[33][34] In the 20th century, condensed milk was heavily marketed in developing regions as a safe, long-life alternative to fresh milk, which was often prone to contamination in areas lacking refrigeration. This positioning drove adoption in tropical climates across Asia, Africa, and Latin America, where it served as an accessible protein source. Corporate milestones included the 1905 merger of Nestlé and Anglo-Swiss, forming Nestlé and Anglo-Swiss Condensed Milk Company, which dominated international trade. Borden, meanwhile, underwent significant restructuring; by the 2000s, its dairy operations were sold amid industry consolidation, with the Borden Dairy Company established in 2009 under new ownership by Grupo Lala following bankruptcy proceedings.[35][36]Production
Manufacturing Process
The manufacturing process of condensed milk begins with raw material preparation, where fresh cow's milk—or occasionally alternatives such as goat's milk—is selected for its bacteriological quality to minimize spore and bacterial contamination. The milk is first pasteurized, typically at temperatures around 72–95°C for 15–30 seconds using high-temperature short-time (HTST) methods, to eliminate pathogens while preserving quality. Standardization follows, adjusting the fat content to approximately 8% and ensuring total solids meet regulatory minima, such as 28% for sweetened varieties under American standards, through the addition or removal of cream or skim milk.[37][38] Evaporation is the core step, conducted in multi-effect falling-film evaporators under vacuum to remove 50–60% of the water content efficiently while maintaining low temperatures of 65–70°C, preventing scorching and protein denaturation. This vacuum pan method concentrates the milk to about twice its original solids level, with pre-heating at 100–120°C for 1–3 minutes often applied beforehand to enhance thermal stability via partial whey protein denaturation. For sweetened condensed milk, cane or beet sugar syrup is added during or after evaporation, achieving a sugar concentration of 62.5–64.5% in the water phase to act as a preservative; the mixture is then homogenized at 5–7.5 MPa (50–75 bar) to stabilize the emulsion and control viscosity, followed by rapid cooling to 18–30°C with lactose seeding to promote fine crystal formation (<10 μm) and prevent grittiness.[37][38] In contrast, for evaporated (unsweetened) condensed milk, homogenization occurs post-evaporation at higher pressures of 5–25 MPa (50–250 bar) to prevent fat separation, after which the product is filled into sterile cans or pouches. Sterilization is then performed in an autoclave at 110–120°C for 15–20 minutes to achieve commercial sterility, ensuring a shelf-stable product without added sugar. Packaging for both types typically involves hermetic sealing in metal cans or flexible aseptic pouches under sanitary conditions to exclude air and contaminants; the process yields approximately 300 ml of condensed milk from 1 liter of raw milk due to the significant water removal.[37]Quality Control and Variations
Quality control in condensed milk production involves rigorous testing to ensure compliance with international standards, such as those outlined by the Codex Alimentarius Commission. For sweetened condensed milk, key parameters include a minimum total solids content of 73%, with milk solids-not-fat at least 28% and milk fat at least 8%, to guarantee proper consistency and shelf stability. Viscosity is monitored to fall within approximately 560 to 800 mPa·s (or centipoise), which affects pourability and product uniformity during packaging. Bacterial load is assessed post-sterilization, with standards requiring less than 500 colony-forming units (CFU) per gram via aerobic plate counts to prevent spoilage.[39][40][41][42] Control measures emphasize pH monitoring, typically maintained between 6.0 and 6.5 during processing to optimize stability and inhibit microbial growth without promoting unwanted reactions. Microbial testing employs standard plate count methods for both aerobic and anaerobic bacteria, alongside checks for osmophilic fungi and pathogens like Bacillus cereus. Hazard Analysis and Critical Control Points (HACCP) protocols are integral, focusing on preventing contamination at critical stages such as raw milk reception, evaporation, and sterilization, through sanitation, temperature controls, and employee hygiene to minimize cross-contamination risks.[39][42][43] Variations in condensed milk production adapt to diverse consumer needs and regional preferences. Non-cow milk sources, such as soy or almond, are used in vegan formulations, where plant-based milks are evaporated and sweetened to mimic traditional texture and flavor; plant-based versions have increased in popularity since 2020 for vegan and lactose-intolerant consumers.[44][45] Low-fat options, like sweetened condensed skimmed milk with a maximum of 1% milk fat, cater to health-conscious markets, while organic lines utilize certified organic milk to meet sustainability demands. Regional adaptations reflect high consumption of sweetened condensed milk in Asian markets, such as Indonesia and Malaysia, where it enhances palatability for local beverages and desserts.[40][46] Production challenges center on controlling the Maillard reaction, a non-enzymatic browning process between milk proteins and sugars that can alter color and flavor if not managed through time-limited exposure at elevated temperatures during processing and low temperatures below 55°C during storage. Shelf-life testing evaluates stability under varying temperatures, from 7°C for refrigerated conditions to 55°C for accelerated simulations; for UHT-treated evaporated condensed milk, products maintain quality for 6-9 months by monitoring browning kinetics and microbial stability, while sweetened varieties achieve 12+ months unopened via sugar preservation.[47][48][49]Nutritional Profile
Key Nutrients and Calories
Condensed milk, available in sweetened and evaporated varieties, provides a concentrated source of macronutrients due to the removal of about 60% of the water from fresh milk. Per 100 grams, sweetened condensed milk contains approximately 321 calories, 8 grams of protein, 8 grams of total fat, and 55 grams of carbohydrates, with the majority of the carbohydrates (around 54 grams) coming from added sugars. In contrast, evaporated milk is unsweetened and less calorie-dense, offering about 134 calories, 7 grams of protein, 7 grams of total fat, and 10 grams of carbohydrates per 100 grams, primarily from natural milk sugars like lactose.[50][51] The following table summarizes key macronutrients per 100 grams for both types, based on USDA data:| Nutrient | Sweetened Condensed Milk | Evaporated Milk |
|---|---|---|
| Calories (kcal) | 321 | 134 |
| Protein (g) | 8 | 7 |
| Total Fat (g) | 8 | 7 |
| Carbohydrates (g) | 55 (54g sugars) | 10 (10g sugars) |
| Dietary Fiber (g) | 0 | 0 |