Non-bacterial ropiness/sliminess in milk — physical and physiological causes Which of the following are recognized non-bacterial reasons for ropiness or sliminess in milk and milk products?

Introduction / Context:
While many cases of ropiness are microbial (for example, Enterobacter or Alcaligenes), plant managers must also recognize non-microbial contributors. These physical or physiological factors can mimic microbial spoilage, leading to misdiagnosis if not considered.

Given Data / Assumptions:

• We are focusing on non-bacterial causes of stringiness/sliminess.
• Examples include components entering milk from udder pathology and cooling-induced protein films.
• Cream thickness can affect perceived viscosity at the top layer.

Concept / Approach:
Mastitis can introduce fibrin clots and leucocytes that yield stringy strands; aggressive cooling can form protein films that behave like threads; high-fat cream layers can appear viscous or slimy. These effects can be mistaken for microbial EPS-driven ropiness, so differential diagnosis requires microscopy, culture, and somatic cell counts.

Step-by-Step Solution:
List non-bacterial mechanisms: mastitis-derived fibrin/leucocytes, thick cream, protein films.Acknowledge each mechanism can create ropiness-like symptoms.Choose the comprehensive option covering all listed factors.

Verification / Alternative check:
Dairy quality manuals underscore verifying microbial growth before attributing ropiness to bacteria, recommending SCC tests and protein film assessments.

Why Other Options Are Wrong:
Each single cause is only part of the picture; “none” ignores well-known physical/physiological contributors to apparent ropiness.

Common Pitfalls:
Immediate assumption of microbial spoilage without SCC or culture; failure to evaluate milk cooling profiles.

Final Answer:
All of the above.