Effect of a pre-treatment of milk with high pressure homogenization on yield as well as on microbiological, lipolytic and proteolytic patterns of "Pecorino" cheese.

The principal aim of this work was to compare Pecorino cheeses obtained from ewes' milk previously subjected to high pressure homogenization (HPH) at 100 MPa with those produced from raw and heat treated ewes' milk. The HPH milk treatment induced a significant increase of the cheese yield and caused a reduction of enterococci, lactococci and yeasts in the curds. Enterococci cell loads remained at lower levels in cheeses obtained from HPH milk over the ripening period.

Effects of sub-lethal concentrations of hexanal and 2-(E)-hexenal on membrane fatty acid composition and volatile compounds of Listeria monocytogenes, Staphylococcus aureus, Salmonella enteritidis and Escherichia coli.

In recent years, the interest in the possible use of natural alternatives to food additives to prevent bacterial and fungal growth has notably increased. Plants and plant products can represent a source of natural alternatives to improve the shelf-life and the safety of food. Some of these compounds, i.

Role of surface-inoculated Debaryomyces hansenii and Yarrowia lipolytica strains in dried fermented sausage manufacture. Part 1: Evaluation of their effects on microbial evolution, lipolytic and proteolytic patterns.

The aim of this work was to study the effects of Debaryomyces hansenii and Yarrowia lipolytica strains, used with lactic acid starter cultures (Lactobacillus plantarum), on the manufacture of dried fermented sausages to understand their role on sausage microbial evolution, lipolytic and proteolytic patterns. The inoculation of the yeast strains did not markedly affect the sausage's microbial flora. The sausages with the yeast strains showed more marked and earlier water activity (a(w)) reductions.

Role of surface-inoculated Debaryomyces hansenii and Yarrowia lipolytica strains in dried fermented sausage manufacture. Part 2: Evaluation of their effects on sensory quality and biogenic amine content.

The aim was to study the effects of Debaryomyces hansenii and Yarrowia lipolytica strains, used with lactic acid starter cultures (Lactobacillus plantarum), in the manufacture of dried fermented sausages in order to understand their effects on volatile profile, biogenic amine content and sensory properties. The experimental data showed that every yeast strain produced a specific profile of volatile metabolic products. The yeasts also gave sausages with distinctive sensory properties.

Effect of high pressure homogenisation of milk on cheese yield and microbiology, lipolysis and proteolysis during ripening of Caciotta cheese.

The principal aim of this work was to compare Caciotta cheeses obtained from cow milk previously subjected to high pressure homogenisation (HPH) at 100 MPa with those produced from raw (R) or heat-treated (P) cow milk. HPH had both direct and indirect effects on cheese characteristics and their evolution during ripening. In particular, HPH treatment of milk induced a significant increase of the cheese yield; moreover, it affected the microbial ecology of both curd and cheese.