Dairy | Issue Cover Collection Published in 2023

Lately, concern about the protease AprX has increased due to its ability to survive UHT treatment and spoil UHT milk. Efficient prediction methods for UHT milk spoilage are currently lacking. The present study aimed to gain more insight into the variability between Pseudomonas strains regarding proteolytic potential. The variability in aprX expression levels in four Pseudomonas strains were related to physical stability, milk proteolysis, and peptidomic cleavage patterns of milk proteins. A positive relationship was observed between the relative expression of aprX and milk proteolysis during storage. The peptide formation analysis showed a similar protein hydrolysis pattern between strains, and high hydrolysis of αs1-caseins during long-term spoilage, putatively due to the activity of AprX, was observed.

Whey cheeses have been produced from the very early steps of cheesemaking practices as a sustainable way to utilize whey, which is the main by-product of cheesemaking. The production of whey cheese is based on the denaturation of whey proteins by heating to 88–92 °C. The specific processing conditions and aspects of the microbiology of whey cheeses are discussed. The special characteristics of whey cheeses, including a high pH and high moisture content, make them susceptible to microbial growth. Due to the limited shelf life of these products, extended research has been carried out to extend the shelf life of whey cheese. Sustainable preservation approaches, such as modified atmosphere packaging, the addition of herbs and/or plant extracts, and bio-preservation methods, are reviewed. Moreover, novel whey cheeses focused on functional properties have developed over the last 10 years.

Podolica is an ancient cattle breed subjected to protection from extinction. The scarce milk production of this breed is used for making caciocavallo Podolico, a cheese with a notable reputation. The present investigation aimed to find specific traits to protect the cheese from imitations. Variant A of α-lactalbumin, a typical characteristic of Podolica milk, was present only in 14% of the animals and cannot be used as a molecular marker. Other peculiarities, such as the low protein-to-fat ratio and some aroma descriptors of the cheese, could be included in a multi-functional protocol for authentication. From this perspective, suitable selection strategies for increasing the frequency of α-lactalbumin A should be evaluated.

The detection of lame cows is a challenging and time-consuming task for dairy farmers. Meanwhile, many farmers use the milking time to monitor the condition of their animals. This study dealt with the question of whether lame and non-lame cows show different behaviors in a milking parlor. A 3D accelerometer attached to the milking cluster detected hind leg activity. Video recordings of head movements, weight shifting, and stepping with the front legs were analyzed. The lame cows showed more hind leg activity during milking, as well as more front steps and weight shifting than the non-lame cows. No relationship between lameness and head movements was seen.