Vietnamese Dairy Factory Case Study: Food Safety Cooling System Upgrade Achieves Zero Non-Conformities with ZILLION

Introduction

Food and beverage manufacturing has some of the most demanding requirements for process cooling equipment of any industry. Cooling systems in food plants must not only deliver precise temperature control for product quality — they must also satisfy food safety regulations, hygiene standards, and third-party audit requirements including HACCP, FSSC 22000, and EU Food Hygiene Regulations. A cooling system failure in a dairy processing plant is not just a production problem; it can trigger a product recall affecting thousands of consumers.

This case study covers how a Vietnamese dairy products manufacturer resolved chronic cooling system problems in their yogurt and fermented milk production lines by replacing an aging and hygiene-inadequate cooling system with a ZILLION industrial water-cooled chiller and cooling tower solution. The plant achieved Food Safety Certification renewal without non-conformities for the first time in three years, reduced cooling-related product losses by 94%, and increased production throughput by 18%.

The Challenge: Outdated Cooling Infrastructure Threatening Food Safety Certification

Background

The customer operates a dairy processing facility in Binh Duong Province, Vietnam, producing pasteurized yogurt, fermented milk drinks, and cheese products for the domestic Vietnamese market and for export to Cambodia and Laos. Their cooling demand is concentrated in two areas:

• Fermentation cooling: Yogurt and fermented milk require precise temperature control at 38-42 degC during the fermentation phase, maintained for 4-6 hours. Temperature deviation of more than 2 degC during fermentation causes off-flavors and incorrect texture.
• Cold chain pre-cooling: Finished yogurt pots are rapidly cooled from 38 degC to below 8 degC within 90 minutes to prevent over-fermentation in the package.

The existing cooling system consisted of two aging ammonia-based refrigeration plant (the plant's original system, installed 15 years prior) serving both the cold storage and the production lines — a configuration that created cross-contamination risks and operational inflexibility.

Problem 1: Ammonia System Approaching End-of-Life with No Budget for Replacement

Ammonia (R717) refrigeration systems are highly efficient but require specialized maintenance expertise and regular safety monitoring. The plant's ammonia system was 15 years old with corroded piping in several sections, and a recent audit revealed that the system's leak detection equipment was no longer compliant with Vietnam's updated industrial refrigeration safety regulations (QCVN 02:2020/BCT). Estimated replacement cost for a comparable ammonia system: VND 4.2 billion (USD 170,000).

Management was unwilling to commit this level of capital to a 15-year-old ammonia technology when modern HFC-based systems offered better energy efficiency and lower maintenance complexity. However, continuing to operate a non-compliant ammonia system posed regulatory and food safety risks.

Problem 2: No Dedicated Cooling for Fermentation Vessels

The yogurt fermentation vats (8 x 5,000-liter vessels) were being cooled by the same ammonia system that served the cold storage rooms. This created two problems:

• Temperature conflict: Cold storage operates at -5 to 0 degC; fermentation requires 38-42 degC. The same system serving both created temperature instabilities in both processes.
• Scheduling inflexibility: Fermentation cycles had to be scheduled around cold storage peak demand periods, causing inconsistent fermentation times and quality variation between batches.

The plant was manually adding ice water to the fermentation jacket to supplement cooling — an approach that was both labor-intensive and unable to provide the precise temperature control required for consistent product quality.

Problem 3: HACCP Non-Conformity Related to Cooling Infrastructure

The plant's most recent FSSC 22000 audit identified a Critical Control Point (CCP) non-conformity related to the cooling system: the shared ammonia system did not have adequate backup capacity to maintain product temperature during a refrigeration failure event. The auditor's recommendation was to either install a dedicated backup refrigeration system or to implement a validated product hold procedure during refrigeration failures.

The hold procedure option required documenting every cooling-related production interruption — averaging 3-4 events per quarter — and holding entire batches pending quality review, creating significant waste and administrative burden.

The Solution: ZILLION HFC-Based Water-Cooled System with Dedicated Fermentation Cooling

System Design Philosophy

Rather than replacing the ammonia system, ZILLION's engineering team designed a hybrid solution that:

• Provided a new, independent HFC-based (R410A) water-cooled chiller dedicated to the production cooling load (fermentation and pre-cooling)
• Utilized the existing ammonia system exclusively for cold storage (where ammonia's high efficiency is most valuable)
• Eliminated the cross-connection between production cooling and cold storage, removing the CCP identified by the FSSC 22000 auditor
• Provided full N+1 redundancy on the production cooling circuit

Selected Equipment

Food Safety Compliance Design Features

• All process cooling circuits use food-grade propylene glycol — no ammonia in production areas
• Automatic temperature logging every 60 seconds — HACCP records generated automatically with timestamp, value, and alarm status
• Alarm integration with plant SCADA — any cooling deviation triggers immediate operator notification via SMS and visual alarm
• N+1 chiller redundancy — automatic transfer to backup chiller within 30 seconds of primary failure, ensuring continuous cooling during equipment faults
• Stainless steel cooling tower sump — meets food industry hygiene standards, no FRP materials in contact with process water
• Sanitary piping and valves — all process water piping uses sanitary-grade tubing and clamp fittings for cleanability

Results After 18 Months of Operation

Food Safety Compliance

Production Performance

Financial Summary

Why HFC Water-Cooled Was the Right Choice for This Application

• Ammonia separation: Moving production cooling to an HFC-based system eliminated ammonia from all production areas, dramatically simplifying the food safety compliance burden and reducing the plant's regulatory risk profile.
• Dedicated capacity: A standalone production cooling system with its own chiller, tower, and controls eliminated the temperature conflicts that had plagued the shared ammonia configuration for 15 years.
• N+1 redundancy: Two identical chillers with automatic transfer eliminated the CCP identified in the FSSC 22000 audit — the cooling system now provides uninterrupted cooling even during equipment maintenance or failure.
• Food-grade glycol: Using food-grade propylene glycol in the process water circuit provides freeze protection for the tower piping (critical in northern Vietnam's winter months when ambient temperatures drop to 8-12 degC) while remaining safe in the unlikely event of a leak into the process.
• Automated HACCP logging: The ZILLION MTC units' built-in data logging capability replaced 180 hours per quarter of manual temperature recording with automated reports — the food safety team could now focus on value-add activities rather than paperwork.

Key Lessons for Food and Beverage Manufacturers

• Do not share refrigeration systems between cold storage and production cooling — temperature demands are fundamentally incompatible, and sharing creates instability in both processes while creating food safety cross-contamination risks
• Ammonia is excellent for large cold storage but creates regulatory burden in production areas — where possible, separate ammonia systems for cold storage from HFC or CO2 systems for production cooling
• N+1 redundancy is not optional for food safety CCPs — the cost of a single chiller failure triggering a product hold or recall vastly exceeds the cost of standby cooling capacity
• Automated temperature logging is a investment, not just a compliance cost — reducing HACCP documentation from 180 hours to 12 hours per quarter is a significant labor productivity improvement that compounds over years
• Glycol in cooling tower circuits is essential in climates with seasonal freezing risk — 20% food-grade propylene glycol provides freeze protection down to approximately -8 degC, appropriate for all Southeast Asian climates

Equipment Used

• 2x ZILLION ZL-25WS Water-Cooled Industrial Chiller (25 kW each, R410A, full N+1 redundancy)
• ZILLION ZCT-40 Counterflow Cooling Tower (40 kW heat rejection, stainless steel sump)
• ZILLION MTC-DW-12 Dual-Zone Fermentation Temperature Controller (12 kW, HACCP data logging)
• ZILLION MTC-SW-18 Production Cooling Temperature Controller (18 kW, rapid cool-down mode)
• Food-grade propylene glycol circulating system with automatic makeup
• SCADA integration for alarm notification and remote monitoring

Frequently Asked Questions

Q: Can glycol be used in food processing cooling applications?
A: Yes — food-grade propylene glycol is approved for use in food and beverage processing cooling systems. It is the same material used in food processing as a heat transfer fluid in many dairy, beverage, and pharmaceutical applications. The key is to use food-grade (not automotive antifreeze) propylene glycol and to maintain the system with regular concentration testing to ensure the glycol ratio stays above 20% for freeze protection.

Q: What is the energy efficiency advantage of water-cooled over air-cooled for food processing?
A: Water-cooled chillers are typically 10-20% more energy-efficient than equivalent air-cooled units because they can achieve lower condensing temperatures in most climates. In tropical Southeast Asia, where ambient temperatures frequently exceed 35 degC, a water-cooled system with a properly sized cooling tower can achieve condenser water temperatures of 30-32 degC — compared to 40-45 degC for an air-cooled condenser in the same ambient conditions. This 10-15 degC reduction in condensing temperature translates directly to 15-20% lower compressor power consumption.

Q: How does a food processing plant justify the investment in a new cooling system?
A: The calculation should include: (1) avoided product losses from cooling failures, (2) avoided regulatory penalties and audit non-conformity costs, (3) additional production throughput from faster and more consistent cooling, (4) reduced HACCP documentation labor, and (5) avoided ammonia system compliance upgrade costs. In this case, the total annual benefit of VND 2.485 billion against an investment of VND 3.2 billion delivered a 15-month payback — well within the typical 5-year planning horizon for food manufacturing capital investments.

Q: What certifications does ZILLION's cooling equipment carry for food applications?
A: ZILLION's industrial chillers and cooling towers are CE certified for European market access and carry equipment documentation suitable for FSSC 22000, HACCP, and ISO 22000 food safety management system documentation. Food-grade materials of construction (stainless steel sumps, food-safe heat transfer fluids, sanitary piping connections) are available as options for all ZILLION production cooling systems.

Conclusion

The transformation of this Vietnamese dairy plant's cooling infrastructure — from a shared, non-compliant ammonia system to a dedicated, redundant, HFC-based water-cooled solution — demonstrates that food safety compliance and operational efficiency are complementary objectives rather than competing priorities.

The 94% reduction in cooling-related product losses, elimination of all FSSC 22000 non-conformities, and 15-month payback period provide a clear template for food and beverage manufacturers facing similar cooling infrastructure challenges.

For food processing plants currently operating aging ammonia systems, or experiencing cooling-related quality problems or regulatory non-conformities, a dedicated ZILLION water-cooled production cooling solution represents a practical and financially justified path to food safety compliance and operational excellence.