Milk Bacteria and Gastrointestinal Tract

Milk is highly nutritious and offers a conducive setting for microbial activity. Nevertheless, the microbial constitution of milk is complex. Origins of these microbes vary from within the animal (colonies in the mammary glands) to external ones such as handling and storage equipment. This chapter will review the predominant microorganisms in cow, goat, sheep, buffalo, donkey, camel, yak, and human milk. The assessment reveals that different microorganisms play diverse roles with relevance to the dairy sector and human health. The chapter will identify certain microbes that are essential in the fermentation of milk, for example, Lactobacillus. Others such as Pseudomonas are a cause for concern because they facilitate spoilage, whereas certain species such as Escherichia coli and Listeria monocytogenes are pathogenic. On the other hand, it will acknowledge health-promoting bacteria (probiotics) such as bifidobacteria and lactobacilli. The role of probiotics in extending the shelf life of fermented dairy products is also discussed. In essence, it will review different types of milk and highlight technologically relevant microorganisms.