Dairy, among other categories of perishable foods, requires the strictest food safety and quality standards, particularly as it relates to extended shelf life (ESL) and aseptic products.

Methods of thermal processing and product handling are required to protect against the potential for product spoilage (or worse) by bacteria such as clostridium botulinum (precursor to the toxin botulism) and other less-harmful spoilage bacteria. These methods meet the requirements of the Food and Drug Administration (FDA) and other regulatory and standardization agencies for low-acid products such as milk and other plant-based products. Producers must ensure absolute certainty in hygiene and food safety, while protecting the nutritional value of the product. 

This approach encompasses not only ensuring acceptable microbial quality of raw materials, but also strongly leverages the hygienic design and operation of equipment critical for processing these products. The most important of these procedures is ultra-high temperature (UHT) processing to support the ESL or aseptic format. This is the essential and final kill-step the product is exposed to prior to packaging.

Aseptic and ESL processing via steam injection

Aseptic processing commercially sterilizes products such as milk, cream, flavored milks and plant-based beverages by rapidly heating to temperatures above 285°F for a brief holding period of four seconds. This destroys all microorganisms, including spore-forming thermophiles. Product is then rapidly cooled, minimizing heat damage prior to homogenization and filling into shelf-stable sterile packaging. Low-acid aseptic products are governed by the FDA via 21 CFR Part 113. ESL dairy products are governed by state authority via the Pasteurized Milk Ordinance (PMO).

ESL processing is similar to that of aseptic processing but only requires products to be brought to a temperature above 280°F for a holding period of two seconds. Packaged ESL product requires refrigeration and can maintain a shelf life of up to 120 days. Innovative equipment suppliers have developed UHT processing equipment capable of producing products in either the aseptic or ESL formats on the same system.

Due to the sensitive nature of milk and milk-like products, the type of thermal processing selected is critical to the quality and taste of the finished products.

Thermal degradation is of primary concern. To reduce potential thermal degradation, it is paramount to heat and cool products as rapidly as possible while still adhering to all regulatory and quality standards. Rapid heating is best achieved through culinary steam injected or infused directly into the product. Rapid cooling is best achieved through immediate exposure of the product to a vacuum environment. These two processes are independent but controlled to ensure that the amount of steam added is the same as the amount of vapor removed in the vacuum process — such that the product is neither concentrated nor adulterated — thereby meeting Grade A dairy standards.

Low-acid aseptic processing enables products to have a “clean label,” maintaining shelf stability for up to 11 months without the need for preservatives. Due to the short, controlled nature of the heating and cooling process, products are minimally affected, ensuring enhanced flavor retention, nutritional value and product integrity.

Dairy manufacturers use one of two methods of direct heating for UHT processing — steam infusion or steam injection: Steam infusion passes the product through a steam atmosphere (milk-into-steam in a vessel); steam injection introduces steam directly into the product flow (steam-into-milk in a venturi). Both methods are followed by flash cooling to remove vapor and prevent dilution.

The choice of system, system design, filler and package are very product dependent as well as very consumer dependent. To ensure product integrity and system efficiency, it is crucial that the choice of process, filler and packaging is made based on the particular products and volumes being processed.

Plant-based ESL and aseptic

Plant-based products are processed using the same methods as dairy products and in many cases fall under the same regulatory jurisdiction. Traditional pasteurization processes can achieve a refrigerated shelf-life of roughly 12 to 21 days. ESL products are processed using methods that bridge the gap between standard pasteurization and long-term room temperature storage — thus achieving refrigerated freshness for 60 to 120 days.

A July 2025 report from the Plant Based Foods Association (PBFA) showed that 59 percent of U.S. households purchased plant-based foods in 2024. The top category where shoppers consumed more plant-based foods instead of animal-based products was milk comprising 40 percent of sales, with coconut, oat and almond milk dominating. The report showed plant-based milk-like products comprising 16 percent of the total U.S. milk market.

PBFA data shows July 2024–2025 (year-over-year) plant-based milk sales were up 9 percent. Comparatively, for the same period, plant-based yogurt sales were up 55 percent, and creamers were up 131 percent, with other dairy alternatives experiencing high growth, as well.

This market growth has led many dairy producers in the US to diversify into plant-based products, with some facilities producing up to 50 percent plant-based SKUs and others transitioning to plant-based products exclusively.

Beyond direct production, some dairy farmers are partnering with plant-based companies to pivot their business models, transitioning their land from animal agriculture to growing crops for plant-based dairy to provide an alternative revenue stream.

Holistic integration of ESL and aseptic processing for dairy

The need for heightened quality and consistency in dairy processing has been pushed forward over the past decades by the end-consumers’ desire for value-added nutrition. Processors have leveraged equipment manufacturers to continue to develop better processing equipment and better processing solutions to fulfill this evolving market.Likewise, these enhanced innovations have been met with the support of USDA, FDA and other regulatory and standard setting organizations.

One process integrator in particular has taken things a step further by approaching plant design and operations in a more holistic manner — wherein plant throughput, efficiency and product quality are paramount. This unique approach sets a new bar — raising the standard for dairy processing — particularly as it relates to value-added ESL and aseptic products.

The ability to achieve seamless process transitions — from ingredient receiving and storage, through product separation, batching and blending, thermal processing to ESL and aseptic standards, through storage and routing to fillers — in addition to clean-in-place (CIP) and sterilize-in-place (SIP) provisions for all processing equipment and piping — is a critical element for achieving the holistic integration of ESL and/or aseptic dairy production.

Latest-generation technologies in aseptic processing of perishable dairy products, when properly integrated, yield considerable benefits in product quality, process throughput and production uptime — which collectively yield increased ROI for processors.

The intention of this review is to further explore holistically integrated technologies from Statco-DSI, which has been a leading provider in the development and integration of ESL and aseptic processes for dairy products for more than 40 years. Its systems encompass: plant design, processing equipment and controls, project management, installation and integration with associated upstream and downstream processes or for full-scale brownfield and greenfield projects.

Industry norms for ESL and aseptic facilities show a much higher incidence of product loss than traditional pasteurized plants. This loss (shrink) can be upwards of 7 to 8 percent of the overall plant’s production. Statco-DSI’s comprehensive approach to plant design and ESL and aseptic process solutions have proven to operate at less than 1 percent shrink. When compared to conventional facilities, it’s clear that Statco-DSI's approach makes an excellent case study for closer review.