http://capridairyworld.org/files/pdf/RUMIN-physico-chem-published.pdf

Physico-chemical characteristics of goat and sheep milk

Listeria monocytogenes is a Gram positive, aerobic, facultative anaerobic and nonacid fast bacterium, which can cause the disease listeriosis in both human and animals. It is widely distributed thoroughout the environment and has been isolated from various plant and animal food products associated with listeriosis outbreaks.

Contaminated ready-to-eat food products such as gravad and cold-smoked salmon and rainbow trout have been associated with human listeriosis in Sweden. The aim of this study was to analyse the occurrence and level of L. monocytogenes in
gravad and cold-smoked salmon (Salmo salar) products packed under vacuum or modified atmosphere from retail outlets in Sweden. Isolated strains were characterized by serotyping and the diversity of the strains within and between
producers were determined with PFGE (Pulsed-field gel electrophoresis). The characterized fish isolates were compared with previously characterized human strains.
L. monocytogenes was isolated from 11 (three manufacturers) of 56 products analysed. This included gravad salmon products from three manufacturers and cold-smoked salmon from one manufacturer. The highest level of L. monocytogenes found was 1500 cfu/g from a cold-smoked salmon product but the level was low (<100 cfu/g) in most of the products. Serovar 1/2a was predominant,
followed by 4b. Three products of gravad salmon harboured more than one serovar. PFGE typing of the 56 salmon isolates detected five Asc I types: four types were identical to human clinical strains with Asc I and one was identical and one was closely related to human clinical strains with Apa I. Isolation of identical or closely related L. monocytogenes strains from human clinical cases of listeriosis and gravad and cold-smoked salmon suggested that these kinds of products are possible sources of listeriosis in Sweden. Therefore, these products should be considered risk products for human listeriosis.

Listeria monocytogenes, a food-borne pathogen

Here, we review what is known about the microorganisms present in raw milk, including milk from cows, sheep, goats and humans. Milk, due to its high nutritional content, can support a rich microbiota. These microorganisms enter milk from a variety of sources and, once in milk, can play a number of roles, such as facilitating dairy fermentations (e.g. Lactococcus, Lactobacillus, Streptococcus, Propionibacterium and fungal populations), causing spoilage (e.g. Pseudomonas, Clostridium, Bacillus and other spore-forming or thermoduric microorganisms), promoting health (e.g. lactobacilli and bifidobacteria) or causing disease (e.g. Listeria, Salmonella, Escherichia coli, Campylobacter and mycotoxin-producing fungi). There is also concern that the presence of antibiotic residues in milk leads to the development of resistance, particularly among pathogenic bacteria. Here, we comprehensively review these topics, while comparing the approaches, both culture-dependent and culture-independent, which can be taken to investigate the microbial composition of milk.

The complex microbiota of raw milk

Increasing the concentrations of beneficial polyunsaturated fatty acids in milk produced by dairy cows in high-forage systems

Traditional cheeses: Rich and diverse microbiota with associated benefits

Somatic cells of goat and sheep milk: Analytical, sanitary, productive and technological aspects ☆

Milk and Cheese Fatty Acid Composition in Sheep Fed Mediterranean Forages with Reference to Conjugated Linoleic Acid cis-9,trans-11

This review summarises the last 10 years' knowledge established on the relationships between the management of animals (genetics, physiology and feeding) and the sensory quality of cheese. In the production of full-fat raw milk cheese, the cow's breed can modify the texture of cheeses because of differences in fat in dry matter content due to variations in the fat/protein ratio in milk. Within the same breed, large differences in texture and taste were observed between cheeses issued from milk differing by the genetic variant of β-casein (in dairy cows) or αs1- casein (in goats). Except in very early or late lactation, the physiological stage had no significant effect on cheese sen- sory characteristics. In contrast, mastitis has a well-known negative impact on cheese sensory pro- perties. Feeding dairy cows or goats with corn silage by comparison with hay or grass silage leads to whiter cheeses and sometimes to differences in flavour. Conserving grass as silage, by compari- son with hay, has no important effect on cheese sensory characteristics, except on colour, which is yellower with grass silage. Conversely, major differences in sensory characteristics were observed between cheeses made with milk produced by cows fed winter diets (based on hay and grass silage) or turned to pasture in the spring. Several recent experiments showed a significant effect of grass' botanical composition on cheese texture and flavour. Those effects are due to the presence in milk of specific molecules or structures directly induced by feeding (carotenes and terpenes) or produced by the animals (plasmin, fatty acids and casein micellar structures) according to their genetic or phy- siological characteristics or under the effect of specific diets. Milk / cheese / sensory characteristic / feeding / genetic characteristic

/pdf/relationships-between-ruminant-management-and-sensory-1r9stseeti.pdf

A. Pirisi

Papers

Somatic cells of goat and sheep milk: Analytical, sanitary, productive and technological aspects ☆

Milk and Cheese Fatty Acid Composition in Sheep Fed Mediterranean Forages with Reference to Conjugated Linoleic Acid cis-9,trans-11

Relationships between ruminant management and sensory characteristics of cheeses: a review

Basic and incentive payments for goat and sheep milk in relation to quality

Managing Mediterranean pastures in order to enhance the level of beneficial fatty acids in sheep milk