Compositional, microbiological, biochemical, volatile profile and sensory characterization of four Italian semi-hard goats' cheeses

Distinctive Traits of Four Apulian Traditional Agri-Food Product (TAP) Cheeses Manufactured at the Same Dairy Plant

This study aimed to highlight the distinctive features of four Traditional Agri-food Products (TAP), namely, Caprino, Pecorino, Vaccino, and Cacioricotta cheeses produced at the same dairy plant to reveal any possible relationships between their microbiological and biochemical characteristics. Two distinct natural whey starter (NWS) cultures were used during Caprino and Vaccino cheesemaking, whereas no starter was used for the other cheeses. Cacioricotta retained the highest concentrations of salt and residual carbohydrates. Lactic acid bacteria dominated the microbiota of the cheeses. Furthermore, staphylococci represented an additional dominant microbial population in Cacioricotta. Although culture-dependent analysis showed that the use of NWS cultures only slightly affected the microbial community of cheeses, 16S metagenetic analysis showed that Lactobacillus helveticus dominated both the NWS cultures and the corresponding Caprino and Vaccino cheeses. This analysis indicated that Staphylococcus equorum and Streptococcus thermophilus dominated Cacioricotta and Pecorino cheeses, respectively. The highest peptidase activities were found in either Caprino or Vaccino. Enzymes involved in the catabolism of free amino acids and esterase showed the highest activity in Pecorino cheese. Each cheese showed a distinct profile of volatile organic compounds, with Pecorino being the richest cheese in carboxylic acids, ketones, and esters, related to lipolysis. The results of this study contribute to valorizing and safeguarding these TAP cheeses, sustaining local farming.

Expression of recombinant human alpha-lactalbumin in the milk of transgenic goats using a hybrid pomoter/enhancer

To improve nutrient content of goat milk, we describe the construction of a vector (pBLAC) containing a hybrid goat β -lactoglobulin (BLG) promoter/cytomegalovirus (CMV) enhancer. We also describe the generation of transgenic goats expressing rhLA by somatic cell nuclear transfer (SCNT). Of 334 one-cell stage embryos derived from three transgenic cell lines and 99 embryos derived from non-transgenic (NT) cells surgically transferred to the oviducts of 37 recipients, two recipients delivered two kids (2%) from the non-transfected line and five recipients delivered six kids (1.8%) from transgenic cell lines, three of which died within 2 days. Compared to the NT donor cells, transfection of donor cells does not negatively affect the development of nuclear transfer embryos into viable transgenic offspring. However, the clone efficiency in cell line number 1 was lower than that in numbers 2 and 3, and in the NT lines (0.9% versus 1.9% 2.4% and 2%; P < 0.05). Two transgenic cloned goats expressed rhLA in the milk at 0.1-0.9 mg/mL. The mammary gland-specific expression vector pBLAC with hybrid BLG/CMV can drive the hLA gene to express in vitro and in vivo. These data establish the basis for use of a hybrid promoter/enhancer strategy to produce rhLA transgenic goats.

Mammals, Milk, Molecules, and Micelles

After a brief description of my family background and school days, my professional career as a dairy scientist is described under three headings: research, teaching, and writing. My research activities fall into four areas: biochemistry of cheese, fractionation and characterization of milk proteins, heat stability of milk, and dairy enzymology. Finally, I offer some advice to young scientists.

Microbial stability and safety of traditional Greek Graviera cheese: characterization of the lactic acid bacterial flora and culture-independent detection of bacteriocin genes in the ripened cheeses and their microbial consortia

The microflora of four batches of traditional Greek Graviera cheese was studied at 5 weeks of ripening, and 200 lactic acid bacteria (LAB) isolates were phenotypically characterized and screened for antilisterial bacteriocins. The cheeses were also analyzed for organic acids by high-performance liquid chromatography and for the potential presence of 25 known LAB bacteriocin genes directly in cheese and their microbial consortia by PCR. All batches were safe according to the European Union regulatory criteria for Listeria monocytogenes, Salmonella, enterobacteria, and coagulase-positive staphylococci. The cheese flora was dominated by nonstarter Lactobacillus casei/paracasei (67.5%) and Lactobacillus plantarum (16.3%) strains, whereas few Streptococcus thermophilus (3.8%), Lactococcus lactis subsp. lactis (0.6%), and Leuconostoc (1.9%) organisms were present. Enterococcus faecium (9.4%) and Enterococcus durans (0.6%) were isolated among the dominant LAB from two batches; however, enterococci were present in all batches at 10- to 100-fold lower populations than mesophilic lactobacilli. Sixteen E. faecium isolates produced antilisterial enterocins. In accordance, enterocin B gene was detectable in all cheeses and enterocin P gene was present in one cheese, whereas the consortia of all cheeses contained at least two of the enterocin A, B, P, 31, L50A, and L50B genes. Plantaricin A gene was also amplified from all cheeses. Mean concentrations of lactic, acetic, citric, and propionic acids in the ripened cheeses exceeded 1.5% in total, of which approximately 0.9% was lactate. Thus, organic acid contents constitute an important hurdle factor for inhibiting growth of pathogens in traditional Graviera cheese products, with LAB bacteriocins, mainly enterocins, potentially contributing to increased cheese safety.