Wastewater treatment techniques for application in fat recovery from waste ice cream

Authors: Plumier, Benjamin; Garcia, Rafael; Renye Jr, John; Miller, Amanda; McAnulty, Michael

Submitted to: Journal of Dairy Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/22/2025
Publication Date: N/A
Citation: N/A

Interpretive Summary: Waste generated during the manufacturing of ice cream costs companies millions of dollars annually due to lost product and disposal fees. This waste material is comprised of valuable food-grade materials, including milkfat, protein and sugars. This study investigated the potential for using coagulation, flocculation, and dissolved air flotation, processes commonly used in wastewater treatment, for the separation of milkfat from waste ice cream. Flocculation was found to be the most efficient method for removing fat from ice cream and was able to separate fat faster and with less mechanical mixing than existing techniques. The aqueous material recovered after fat extraction was shown to support the growth of lactic acid bacteria and yeast, suggesting it can serve as a fermentation substrate for production of antimicrobial peptides or ethanol, respectively. Further studies are needed to develop methods for separating the extracted fat from the chemical flocculant, and to determine potential applications for the extracted fat and fermentation end products.

Technical Abstract: Ice cream is a popular dairy food in the United States. Unfortunately, there is a significant loss of product during production, despite being of acceptable quality. There are many valuable components in waste ice cream (WIC) that can be utilized if separated. To investigate the potential of wastewater treatment techniques as a means of recovering fat from WIC, a variety of flocculants were tested on five ice cream varieties. The flocculation procedure was able to concentrate 89% to 100% of the total fat in 50%-70% of the original volume. The amount of fat recovered was consistently superior to that recovered from previous centrifugation techniques. Increasing ice cream temperature resulted in similar fat recovery, but required the use of significantly less flocculant, decreasing from 25ml at 13.5°C to 6.7ml at 38°C per 100 g ice cream. Additionally, the remaining aqueous stream was shown to support the growth of lactic acid bacteria and yeast, resulting in the production of the broad spectrum bacteriocin thermophilin 110 and ~10% ethanol, respectively. This study demonstrates the potential for utilizing flocculation strategies to efficiently concentrate fat from waste ice cream for recovery, and to generate a defatted stream for use in ethanol and bacteriocin production.