The Process of Making Plastic Cream: A High-Fat Dairy Product

In the dairy industry, not all creams are created equal. While most people are familiar with light cream or whipping cream, there’s a lesser-known but industrially significant product called plastic cream. With a fat content ranging from 60% to 85%, plastic cream is a thick, paste-like dairy product that plays a key role in butter oil production and milk standardization. Despite its high fat content – comparable to butter – plastic cream maintains a unique fat-in-water emulsion structure, setting it apart from butter entirely. Let’s break down what plastic cream is, how it’s made, and why it matters to dairy processing.

What is plastic cream? 🔗

Plastic cream is the most viscous type of cream produced in the dairy industry. Its texture resembles a thick paste rather than a pourable liquid, which is why it earns the name “plastic.” According to the U.S. Dairy Export Council, plastic cream typically contains around 80% milkfat. It looks and feels similar to butter in consistency, but here’s the crucial difference: butter is a water-in-fat emulsion (where tiny water droplets are dispersed in a continuous fat phase), while plastic cream remains a fat-in-water emulsion (also called oil-in-water), even at these extremely high fat levels.

This distinction matters because the emulsion type determines how the product behaves during further processing. Since plastic cream keeps fat globules suspended in an aqueous (water-based) phase, it can be handled and processed differently than butter – particularly when the goal is to extract pure milk fat or to blend it with other dairy components.

Composition of plastic cream 🔗

The typical composition of plastic cream is roughly 80% fat, 18% water, about 0.7% protein, 1% lactose, and 0.1% ash. Compared to heavy cream (which has about 36-37% fat and 57% water), plastic cream has far less moisture and non-fat solids. This concentrated composition is what makes it so valuable as a raw material for producing butter oil and for adjusting the fat content of standardized milk products.

How is plastic cream different from butter? 🔗

At first glance, plastic cream and butter seem almost identical – both contain around 80% fat and have a thick, semi-solid texture. However, they are fundamentally different products due to their emulsion structure.

During butter manufacturing, cream is churned until the fat-in-water emulsion breaks and inverts into a water-in-fat emulsion. The fat globules clump together, releasing buttermilk, and the result is a continuous fat phase with small water droplets trapped inside. Plastic cream, on the other hand, never undergoes this phase inversion. The fat globules remain dispersed in the aqueous phase, held in place by their natural fat globule membrane consisting of phospholipids and proteins.

This difference in emulsion type has practical consequences. Plastic cream can be more easily converted into butter oil through centrifugal separation because its fat is still in a form that separators can efficiently handle. It can also be blended directly with skim milk to produce standardized milk – something that’s more complex to do with butter, which first needs to be melted and re-emulsified.

Methods of preparing plastic cream 🔗

There are two primary methods for producing plastic cream, and both require that the starting material – whether cream or whole milk – is pasteurized before processing to ensure microbiological safety.

Method 1: Re-separation of normal cream 🔗

The first and more common approach involves a two-step separation process. Fresh whole milk is first run through a standard cream separator to produce normal cream with a fat content of about 30-40%. This cream is then passed through the separator a second time – a process known as re-separation – to further concentrate the fat.

During re-separation, the cream is typically heated to around 50°C to ensure the fat is in a liquid state, which improves separation efficiency. The centrifugal force pushes the heavier skim milk fraction outward while the lighter fat concentrates at the centre, yielding a cream with 60-85% fat content. The by-product of this second separation is a low-fat fraction sometimes called “separator buttermilk,” which can be recycled back into the process or used in other dairy products.

Method 2: Using a plastic cream separator 🔗

The second method uses a specially designed plastic cream separator that can produce high-fat cream directly from whole milk in a single pass. These separators are engineered with specific disc configurations and pressure settings that allow them to yield cream with fat content approaching 80% without the need for a re-separation step.

As noted in dairy technology literature, modern cream separators can be adjusted to produce cream with fat levels ranging from as low as 25% to as high as 80%. The fat content is controlled by adjusting the back pressure on both the skim milk and cream outlets. A tighter restriction on the cream outlet concentrates more fat into a smaller volume, resulting in higher-fat cream.

While this single-pass method is more efficient, it requires specialized, higher-capacity equipment and precise process control, making it more suitable for large-scale dairy operations.

Key processing considerations 🔗

Producing plastic cream isn’t simply about spinning milk faster or longer in a separator. Several factors need careful management to ensure a stable, high-quality product.

Temperature control 🔗

Temperature plays a critical role throughout the process. The milk or cream must be warmed to approximately 50°C before separation. At this temperature, milk fat is fully liquid, which allows for more efficient separation. If the temperature is too low, solid fat crystals can interfere with the process and reduce separation efficiency. If it’s too high, there’s a risk of damaging the fat globule membrane and causing unwanted fat release.

Pasteurization 🔗

Whether starting from whole milk or pre-separated cream, pasteurization is essential before the plastic cream separation step. This heat treatment destroys pathogenic bacteria and inactivates enzymes like lipase that could break down fat and cause off-flavours during storage. For cream with very high fat content, care must be taken during pasteurization – as the DairyPulse technical resource notes, heat treatment of heavy creams can sometimes cause partial churning if not properly managed.

Emulsion stability 🔗

Maintaining the fat-in-water emulsion at such high fat levels is inherently challenging. The fat globules in plastic cream are packed very closely together, and even minor disturbances – rough handling, temperature swings, or excessive agitation – can destabilize the emulsion and cause partial phase inversion. Proper handling protocols and temperature-controlled storage are essential to keep plastic cream in its desired emulsion state.

Applications of plastic cream in the dairy industry 🔗

Plastic cream is not a retail product – you won’t find it on supermarket shelves. It’s an industrial intermediate used primarily in two areas: butter oil production and milk standardization.

Butter oil and anhydrous milk fat production 🔗

One of the most important uses of plastic cream is as a starting material for manufacturing butter oil, also known as anhydrous milk fat (AMF). AMF is a nearly pure fat product containing at least 99.8% milk fat, with almost all water and non-fat solids removed. It is widely used in the food industry for bakery products, confectionery, chocolate, ice cream, and the production of recombined milk.

The AMF production process from cream involves concentrating the fat to about 75% or higher (which is essentially what plastic cream already achieves), then using a homogenizer to cause phase inversion – breaking the fat-in-water emulsion and converting it into a water-in-fat system. After phase inversion, further centrifugal separation concentrates the fat to approximately 99.5%. The final product is then vacuum-dried and cooled for packaging. Starting with plastic cream rather than regular cream reduces the number of concentration steps needed, making the process more efficient.

Preparation of standardized and recombined milk 🔗

Plastic cream is also used to adjust the fat content of milk to meet regulatory standards or commercial specifications. In standardized milk production, plastic cream can be blended with skim milk or low-fat milk to achieve precise fat levels – for example, 3.0% for whole milk, 2.0% for reduced-fat milk, or 1.0% for low-fat milk. Because plastic cream has such a high fat concentration, only a small quantity is needed to raise the fat content of a large volume of milk.

In countries that rely on recombined milk (where fresh milk supply is insufficient), plastic cream can serve as an alternative to butter oil. Skim milk powder is dissolved in water, and plastic cream is blended in to provide the required fat content. This approach can be simpler than using AMF because it avoids the need to melt and re-emulsify a solid fat product.

Other dairy product applications 🔗

Beyond butter oil and standardization, plastic cream can be used as a high-fat ingredient in the manufacture of cheese, frozen desserts, and other value-added dairy products. Its concentrated fat content means that manufacturers can efficiently boost the richness and mouthfeel of products without adding excessive volume.

Storage and shelf life 🔗

Plastic cream has a notable advantage when it comes to storage: it can be frozen for long-term preservation. In the frozen state, plastic cream has excellent keeping quality and can be stored for extended periods – potentially several years – without significant deterioration. This makes it an economical option for dairy operations that need to stockpile milk fat during periods of surplus production and use it later when demand increases or fresh milk supply is limited.

The frozen storage capability also provides an advantage in terms of transportation economy. Because plastic cream has roughly 80% fat versus the 36% in heavy cream, the same amount of milk fat can be shipped in less than half the volume, reducing both shipping costs and storage space requirements.

Challenges in plastic cream production 🔗

While plastic cream is a valuable industrial product, its production comes with specific challenges. The high fat concentration makes it inherently unstable compared to lower-fat creams, requiring strict adherence to temperature and handling protocols. Any lapse can lead to partial churning or emulsion breakdown, resulting in an unusable product.

The equipment requirements are also significant. Producing plastic cream requires high-performance centrifugal separators capable of handling the extreme fat concentrations, along with temperature-controlled piping, storage tanks, and filling systems. For dairy operations using the plastic cream separator method, the capital investment in specialized equipment can be substantial.

Quality control is another important consideration. The fat content, emulsion stability, and microbiological quality of plastic cream must be carefully monitored at every stage of production. Modern dairy plants use inline sensors and automated control systems to maintain consistency, but smaller operations may find achieving the required precision more difficult.

Why plastic cream matters for the dairy sector 🔗

Plastic cream may not be glamorous, but it’s a workhorse of the dairy industry. It enables efficient production of butter oil and anhydrous milk fat, supports milk standardization programs, and provides a compact, shelf-stable form of milk fat for transportation and storage. In countries like India, where ghee and butter oil are essential dietary staples, and in regions that depend on recombined milk products, plastic cream plays a particularly important role in the dairy supply chain.

As dairy processing technology continues to advance – with more efficient separators, better inline monitoring, and improved cold chain logistics – the production and use of plastic cream is likely to become even more streamlined and widespread.

What do you think? How might the growing demand for recombined dairy products in developing countries influence the production and trade of high-fat cream products like plastic cream? And in what ways could improvements in separator technology further reduce the cost and complexity of plastic cream production?

References

1. https://www.thinkusadairy.org/assets/documents/Customer%20Site/C3-Using%20Dairy/C3.7-Resources%20and%20Insights/03-Application%20and%20Technical%20Materials/Cream_Spec.pdf
2. https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/cream
3. https://dairyprocessinghandbook.tetrapak.com/chapter/centrifugal-separators-and-milk-standardization
4. https://ebooks.inflibnet.ac.in/ftp04/chapter/cream-separation-in-dairy-industry/
5. https://dairypulse.org/cream/
6. https://dairyprocessinghandbook.tetrapak.com/chapter/anhydrous-milk-fat-amf-and-butter-oil
7. https://dairyprocessinghandbook.tetrapak.com/chapter/recombined-milk-products
8. https://www.uoguelph.ca/foodscience/node/1929/