Dairy Microbiology Lecture II

Study Notes

Lecturer: Karima Galal Abdel Hameed, Professor of Milk Hygiene, Head of Food Hygiene Department, Faculty of Vet. Med., SVU
Date: 21/14/2024
Lecture type Lecture II

Classification: Microorganisms in milk are categorized as:
- Non-pathogenic (desirable & spoilage)
- Pathogenic (disease-producing bacteria)

Classification based on origin:
- Disease of animal origin (Zoonotic)
- Disease of human origin (Epidemic)
- Disease of both animal & human origin
- Disease of environmental origin
Causative organisms:
- Bacteria & Viruses
- Fungi & Protozoa
- Allergens & toxins

Animal & human origin: Zoonotic diseases (raw milk) & Epidemic disease (heat-treated milk) originate from animals and humans, respectively. Environmental origin occurs.
Environmental origin: Diseases come from the environment.

Bovine tuberculosis: Chronic infectious bacterial disease caused by Mycobacterium bovis from drinking infected raw milk. Gram-positive bacterium, acid-fast bacilli.
Brucellosis: Chronic infection leading to recurrent/chronic fever in humans due to contaminated unpasteurized dairy products or contact with infected animals. Causative organism: Brucella.
Leptospirosis: Sporadic bacterial disease with varying severity transmitted via contact with infected animal urine. Causative organism: Leptospira.
Listeriosis: Bacterial disease characterized by monocytes in peripheral blood of immunocompromised patients and elders. Causative organism: Listeria monocytogenes.
Pasteurellosis: Common wound infection following animal bites. Causative organism: Pasteurella multocida.
Anthrax: Acute bacterial infection; can be fatal rapidly. Causative organism: Bacillus anthracis.
Actinomycosis: Bacterial disease affecting submaxillary bone in humans, causing lumpy jaw, and affecting the udder in animals. Causative organism: Actinomyces bovis.

Foot and Mouth Disease (FMD): Acute, highly infectious viral disease affecting cloven-footed animals (cows, buffaloes, sheep, goats). Causative organism: Foot and mouth disease virus (Picornaviridae).
Rabies: Zoonotic, fatal viral disease affecting the central nervous system. Causative organism: Rabies virus.
Cow pox: Viral infection between cattle and milkers via skin contact, during milking. Causative organism: Cow pox virus (Poxviridae).
Tick-borne encephalitis: Viral disease affecting goats. Causative organism: Tick-borne encephalitis virus.
Rift Valley fever (RVF): Viral zoonosis, affecting animals and humans, can cause severe disease and significant economic losses; sheep and goats are susceptible. Causative organism: RVF virus (Phlebovirus genus).

Toxoplasmosis: Protozoal disease transmitted through ingestion of raw or improperly pasteurized milk containing trophozoites. Causative organism: Toxoplasma gondii trophozoite.
Amoebiasis: Protozoal disease caused by ingestion of raw or improperly pasteurized milk containing cysts. Causative organism: Entamoeba histolytica cyst.

Q fever (Coxiellosis): Acute febrile disease of humans caused by Coxiella burnetii. Dairy animals are a reservoir, ticks and insects can transmit the disease and milk can be a transmission vehicle.

Many methods exist for diagnosing and controlling various diseases. These include testing for the causative organisms, treating affected animals, and controlling the environmental spread of the disease.