Study Finds 29% Of All Pre-Grated Cheeses Adulterated With Palm Oil

A recent study found that 29 percent of all samples of pre-grated hard cheeses sampled were “certainly adulterated with palm oil.”

That combined with nearly half of the adulterated samples possessing lipid fractions composed of greater than 50 percent palm oil “shows a rather brazen attitude in this industry regarding the commission of fraud through the adulteration of these products,” said the study, which was published in the journal Molecules.

Hard cheeses are a widely consumed product througouut much of the world and pre-grated products made from these cheeses are popular as a condiment for many foods, noted the study, which was written by Colleen L. Ray, Madison P. Bylo, Jonny Pescaglia and C. Michael Greenlief of the University of Missouri’s Department of Chemistry; and James A. Gawenis of Sweetwater Science Laboratories, Glasgow, MO.

The majority of these pre-grated products are composed of grated cheese with small amounts of antimycotic preservatives such as potassium sorbate, which was used in many samples in this study. Anticaking agents such as cellulose powder were also used in
most samples tested.

Adulteration of these cheese products has previously been discovered involving the addition of cellulose powder as a filler at levels far beyond those sufficient to prevent caking, the study noted.

Nuclear Magnetic Resonance (NMR) spectroscopy analysis of food products is a powerful tool for the detection of adulteration, according to the study. It is ideal for analysis of this type due to high sample throughput, the ability to discriminate based on structural differences of metabolites with similar masses, and the ability to examine samples in either their native state or with little sample preparation.

Analysis of cheese via NMR has been performed for quite some time, the study said. However, previous works were typically focused on aqueous extracts in order to determine point of origin, or a combination of origination and the process of cheese ripening.

The aim of this study was to create and test a method for the analysis of hard cheese products with the aim of detecting vegetable oil adulterants.
The method was designed to be rapid in order to facilitate its use in high-throughput situations. The difference in lipid profiles betwen cheese and vegetable oils makes the detection of adulterated cheeses relatively straightforward with a simple ratiometric analysis.

For the study, nine ungrated samples and one grated sample of various cheeses were analyzed to ascertain a lipid profile of unadulterated cheese samples. Of these baseline samples, three were Parmesan, two were Romano, and one was Asiago. To gain a broader understanding of cheese lipid profiles, one sample of Mimolette, one sample of Piave cheese, and one sample each of ungrated and pre-grated Mozzarella were also analyzed.

All market survey grated hard cheese samples were obtained from retailers, restaurants, and public school cafeteria kitchens. All samples were composed of Parmesan, Romano, Asiago, and combinations thereof. Canola, grapeseed, peanut, olive, high oleic sunflower, high oleic safflower, high linolenic safflower, soybean, and palm oils were purchased from local and online retailers and used as received.

“This study revealed a previously undiscovered method of adulterating pre-grated bovine hard cheeses for economic purposes,” the study said. “Palm oil itself is a clever adulterant owing to its semi-solid state at room temperature, similar color to cheese, and low price compared to cheese.”

The 52 samples tested in this study are “by no means an exhastive survey of all pre-grated hard cheeses sold, however, it does reveal a new frontier in food adulteration,” the study continued. The method described in the study “will make the detection of this new type of food adulteration straightforward and aid in combating the problem.”

“The analysis of food products with NMR spectroscopy is a powerful tool for the detection of adulteration,” said Greenlief, director of the MU Proteomics Center and Nuclear Magnetic Resonance Facility and corresponding author of the study. “It is ideal for analyses of this type due to a high sample throughout, the ability to discriminate based on structural differences of metabolites with similar masses, and the ability to examine samples in either their native state or with little sample preparation.”

“Food adulteration leads to a product that is cheaper to produce but is sold as the original product,” Ray said. “This results in consumers buying a product that is not what they expected and is often inferior to the unadulterated version. Therefore, we wanted to explore the authenticity of these products.”
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