For process water used in dairy plants, what is the recommended microbiological limit for proteolytic and/or lipolytic organisms to avoid product spoilage and enzyme-mediated defects?

Introduction / Context:
In the dairy industry, process water quality directly influences product safety and shelf life. Proteolytic and lipolytic microorganisms produce enzymes that degrade proteins and fats, causing bitterness, rancidity, or texture defects. Setting strict microbiological limits for these organisms in incoming and utility water helps maintain product quality in milk, cheese, yogurt, and ice cream plants.

Given Data / Assumptions:

• Water is used for equipment rinsing, ingredient dilution, and CIP steps.
• Proteolytic/lipolytic organisms are measured as counts per milliliter.
• Industry guidance sets low allowable counts to minimize enzyme carryover.

Concept / Approach:
Even small populations of protease- and lipase-producing microbes can release thermostable enzymes that survive pasteurization and later degrade dairy products. Practical standards therefore constrain these counts to very low levels. Among the listed choices, the commonly cited criterion is not more than 10 per ml, balancing practical monitoring with stringent quality control to prevent spoilage issues and off-flavors.

Step-by-Step Solution:

Verification / Alternative check:
Historical QA/QC guidelines and plant SOPs frequently prescribe very low allowable counts for these functional groups due to their outsized impact on flavor and texture stability.

Why Other Options Are Wrong:

• Counts of 15 or 20 per ml increase risk of enzyme carryover and spoilage.
• Count of 5 per ml is more stringent than typical practice and may be unnecessarily restrictive given monitoring variability.

Common Pitfalls:
Relying solely on total plate count; functional groups like psychrotrophs with proteolysis/lipolysis can cause defects even when overall counts are modest.

Final Answer:
10 proteolytic and/or lipolytic organisms per ml