Sweetened Condensed Milk (SCM) is a beloved ingredient in countless desserts and beverages worldwide, known for its rich and creamy texture. SCM is produced by evaporating milk and adding sucrose, while Recombined Sweetened Condensed Milk (RSCM) is made by mixing milk solids, water, and other ingredients. These products have a long shelf-life, making them a convenient choice in areas without refrigeration. As producers strive to meet consumer demands for high-quality SCM, understanding key factors such as microbiology, crystallization, and age thickening is essential. By implementing best practices and maintaining a commitment to excellence, producers can provide SCM and RSCM that satisfies both taste and longevity, setting themselves apart in the market.
Shelf-Life and Spoilage Prevention
One of the standout features of SCM is its extended shelf-life. This remarkable durability is a result of the low presence of spoilage organisms within the product. The high concentration of sucrose in SCM creates high osmotic pressure, effectively inhibiting spoilage organisms. To maximize shelf-life, it's essential to ensure that the sucrose content falls within a specific range: above 62.5% to inhibit most spoilage organisms but below 64.5% to prevent sucrose crystallization.
The microbiological quality of SCM hinges on the quality of the raw materials used in production. It is essential to pay close attention to three critical points:
Microbiological problems, particularly post-contamination during filling, can lead to spoilage. To prevent this, state-of-the-art technology, proper filling techniques and hermetic seals are essential.
Crystallization for Texture and Quality
The crystallization of lactose is vital for SCM's texture and mouthfeel. Small lactose crystals (max 10µm long) are preferred to avoid sedimentation and a sandy texture. Achieving this requires precise cooling, seeding with lactose, and maintaining a consistent storage temperature. Fluctuations in storage temperature can lead to larger crystals. Additionally, crystallization of sucrose may occur with high sucrose concentrations and/or low storage temperatures.
Age Thickening: Understanding and Mitigation
Age thickening, characterized by increased viscosity over time, poses a challenge in SCM and other long-shelf-life dairy products. It results from heat-resistant microbial proteases and physicochemical changes in casein. To reduce this, the following is important.
How Sweetened Condensed Milk is made: