Effetto della temperatura di conservazione del latte, dalla raccolta all'affioramento, sulla microflora del latte, del sieroinnesto e del formaggio Trentingrana

This PhD research is part of a project addressed to improve the quality of Grana Trentino production. The objectives were to evaluated if milk storage and collection procedures may affect cheese-making technology and quality. Actually the milk is collected and delivered to the cheese factory just after milking in 50 L cans without refrigeration or in tanks cooled at 18 °C. This procedure is expensive (two deliveries each day) and the milk quality is difficult to preserve as temperatures are not controlled. The milk refrigeration at the farm could allow a single delivery to the dairy. Therefore it could be a good strategy to preserve raw milk quality and reduce cheese spoilage. This operation may, however, have the drawbacks of favouring the growth of psychrotrophic bacteria and changing the aptitude of milk to coagulation. With the aim of studying the effect on milk and cheese of traditional and new refrigerated technologies of milk storage, two different collection and creaming technologies were compared. The trials were replicated in three cheese factories manufacturing Grana Trentino. Every cheese-making day, about 1000 milk liters were collected from always the same two farms in the different collection procedures (single or double). Milk was processed to produce 2 wheels of Grana trentino every day. During the refrigerated trials, milk was collected and stored at the farm in a mixed tank at 12 or 8 °C and then was carried to the dairy in truck once a day. 112 cheese making day were followed: 56 for traditional technology and 56 for the refrigerated one. Each one of these two thechnologies lead to different ways of creaming: long time in the traditional one and shorter in the new one. For every cheese making day we recorded time, temperatures and pH during the milk processing to cheese. Whole milk before ceraming, cream and skim milk after creaming, vat milk and whey were sampled during every cheese-making day for analysis. After 18 months ripening we opened 46 cheese wheels for further chemical and microbiological analyses. The trials were performed with the aim of: 1 estimate the effect of storage temperatures on microbial communities, physico-chemical or/and rheological differences of milk and skim milk after creaming. 2 detect by culture dependent (plate counts) and indipendent (DGGE) methodolgies the microbial species present in whole, skimmed milk, cream and cheese sampled under the rind and in the core; 3 estimate the physico-chemical characteristics, the proteolytic activity, the content of free aminoacids and volatile compounds in 18 months ripened Grana Trentino cheeses from different storing and creaming of milk technologies. The results presented are remarkable since this is the first in-deep study presenting microbiological and chemical analysis of Grana Trentino that even if belonging to Grana Padano Consortium, it is clearly different in the milk and in the manufacturing technology.

Airway Basal Cell Vascular Endothelial Growth Factor-mediated Cross-Talk Regulates Endothelial Cell Dependent Growth Support of Human Airway Basal Cells

The human airway epithelium is a pseudostratified heterogenous layer comprised of cili-ated, secretory, intermediate and basal cells. As the stem/progenitor population of the airway epi-thelium, airway basal cells differentiate into ciliated and secretory cells to replenish the airway epithelium during physiological turnover and repair. Transcriptome analysis of airway basal cells revealed high expression of vascular endothelial growth factor A (VEGFA), a gene not typically associated with the function of this cell type. Using cultures of primary human airway basal cells, we demonstrate that basal cells express all of the 3 major isoforms of VEGFA (121, 165 and 189) but lack functional expression of the classical VEGFA receptors VEGFR1 and VEGFR2. The VEGFA is actively secreted by basal cells and while it appears to have no direct autocrine function on basal cell growth and proliferation, it functions in a paracrine manner to activate MAPK signaling cascades in endothelium via VEGFR2 dependent signaling pathways. Using a cytokine- and serum-free co-culture system of primary human airway basal cells and human endothelial cells revealed that basal cell secreted VEGFA activated endothelium to ex-press mediators that, in turn, stimulate and support basal cell proliferation and growth. These data demonstrate novel VEGFA mediated cross-talk between airway basal cells and endothe-lium, the purpose of which is to modulate endothelial activation and in turn stimulate and sustain basal cell growth.