Thermal treatments are used to improve milk microbial safety, shelf life, and biological activity of some of its components. However, thermal treatments can reduce the nutritional quality of milk, affecting the molecular structure of milk proteins, such as lysozyme, which is a very important milk component due to its antimicrobial effect against gram-positive bacteria. Jenny milk is characterized by high lysozyme content. For this reason, in the last few years, it has been used as an antimicrobial additive in dairy products as an alternative to hen egg white lysozyme, which can cause allergic reactions. This study aimed to investigate the effect of pasteurization and condensation on the concentration and antimicrobial activity of lysozyme in jenny milk. Furthermore, lysozyme quantity and activity were tested in raw and pasteurized milk after condensation at 40 and 20% of the initial volume. Reversed-phase HPLC was performed under fluorescence detection to monitor lysozyme in milk samples. We evaluated the antimicrobial activity of the tested milk against Bacillus megaterium, Bacillus mojavensis, Clavibacter michiganensis, Clostridium tyrobutyricum, Xanthomonas campestris, and Escherichia coli. Condensation and pasteurization did not affect the concentration or antimicrobial activity of lysozyme in jenny milk, except for B. mojaventis, which showed resistance to lysozyme in milk samples subjected to heat treatments. Moreover, lysozyme in jenny milk showed antimicrobial activity similar to synthetic antibiotics versus some gram-positive strains and also versus the gram-negative strain X. campestris.

The aim of this research was to study the influence of lactation stage and foaling season on some qualitative aspects of milk in South Italian jenny rearing. Milk samples were collected monthly from 23 jennies, that foaled in 2 different periods: spring and summer. On milk, the following parameters were measured: pH and titratable acidity; protein, fat, lactose, dry matter, and ash contents; and somatic cell count. Analysis of variance showed the effect of foaling season and of lactation stage. Milk production was highest in summer at 30 d and 60 d (1.58 and 1.78 L, respectively), and in spring at 120 d (1.25 L). The total protein content was highest in summer lactation at 30 d and 90 d (14.8 and 13.9 g/L). Lactose, dry matter, and ash contents (g/L) were highest in summer lactation at 30 d (54.0, 78.1, and 5.0 respectively). Jenny milk was shown to be poor in protein and fat and rich in lactose. Producing jenny milk could be an interesting, profitable, and alternative activity for farmers, mainly in southern marginal areas.

The study aimed to evaluate the effects of linseed and oregano supplementation to the diet of goats on fatty acid profile and sensory properties of Padraccio, a typical cheese produced during spring through summer in the Basilicata region (southern Italy). Extruded linseed and dried oregano inflorescences were integrated in the pelleted concentrate supplementation (500 g/head per day) in 21 grazing goats that were randomly assigned, 7 per group, to the following experimental treatments: concentrate, concentrate with addition of linseed, and concentrate with addition of linseed and oregano. Pooled milk from each group was used in cheese-making. From a nutritional perspective, integration of extruded linseed in the goat diet improved the fatty acid profile of Padraccio cheese. Moreover, the cheese from this group evidenced the highest scoring on color, flavor, texture, and overall liking.

The occurrence of late blowing defects in cheese produces negative effects on the quality and commercial value of the product. In this work, we verified whether the addition of raw jenny milk to bulk cow milk reduced the late blowing defects in semihard cheeses. During cheesemaking, different aliquots of jenny milk were poured into 2 groups of 4 vats, each containing a fixed amount of cow milk. A group of cheeses was created by deliberately contaminating the 4 vats with approximately 3 log10 cfu/mL milk of Clostridium tyrobutyricum CLST01. The other 4 vats, which were not contaminated, were used for a second group of cheeses. After 120 d of ripening, some physical, chemical, and microbiological parameters were evaluated on the obtained semihard cheeses. Differences in sensory properties among cheeses belonging to the uncontaminated group were evaluated by 80 regular consumers of cheese. Our results showed that the increasing addition of jenny milk to cow milk led to a reduction of pH and total bacterial count in both cheese groups, as well as C. tyrobutyricum spores that either grew naturally or artificially inoculated. We observed a progressive reduction of the occurrence of late blowing defects in cheese as consequence of the increasing addition of jenny milk during cheese making. Moreover, the addition of jenny milk did not affect the acceptability of the product, as consumers found no difference among cheeses concerning sensorial aspects. In conclusion, the important antimicrobial activity of lysozyme contained in jenny milk has been confirmed in the current research. It is recommend for use as a possible and viable alternative to egg lysozyme for controlling late blowing defects in cheese.

The addition of jenny milk during cheesemaking has been recommended as a viable alternative to egg lysozyme for controlling late blowing defects. However, little is known on the sensory properties of the cheeses made with jenny milk. In this study, the effect of the addition of jenny milk during cheesemaking on sensory properties and consumer acceptability of cheese was evaluated. A sensory profile was carried out by 10 trained panelists on 4 cow milk cheese types. Two types of cheeses were made by adding jenny milk to cow milk during cheesemaking; the cheeses were then left to ripen for 45 and 120 d. The remaining 2 cheese types were made with only cow milk and were also left to ripen for 45 and 120 d. The attributes generated by a quantitative descriptive analysis sensory panel were effective for discriminating the 4 products. Among them, added jenny milk samples aged for 45 d had the highest intensity of some appearance descriptors (structure and color uniformity), as well as the highest intensity of sweetness. The analysis of acceptability data obtained from 89 consumers showed that added jenny milk aged for 45 d was the most preferred type of cheese, whereas no significant differences were found among the other products, which had higher intensity of bitter, salty, acid milk, and so on.