Freeze-Dried Pet Food Standard NY/T 4839: 6 Metrics Co-Packers Must Align

Since May 1, 2026, NY/T 4839-2025 General Requirements for Freeze-Dried Pet Food has been in force. Six months in, **freeze-dried pet food contract manufacturing** has moved from "we do it by experience" to "we do it to a standard."

If you are evaluating **freeze-dried pet food manufacturers** or already sampling with a co-packer, these six metrics must be aligned at the contract and sample stage. Otherwise, compliance problems surface only after scale-up.

1. Ingredients: Fresh Frozen Meat, Not Re-Thawed Stock

The standard requires:

• Fresh or frozen fresh meat stored at -18°C or below—not room-temperature jerky, not re-thawed stock;
• Species must match the label (chicken is chicken, not duck passed off as chicken);
• Seafood must declare species of origin.

Whether the freeze-dried co-packer runs a dedicated fresh-meat cold room and physically separates it from jerky lines is the first filter.

2. Process: Traceable Lyophilization Curves

Core process parameters:

• Pre-freezing temperature typically -35°C to -40°C;
• Sublimation-stage vacuum ≤ 100 Pa;
• End point measured by **water activity (Aw)**, typically ≤ 0.6.

The standard requires lot-by-lot process curve records. A reliable **freeze-dried pet food co-packer** shows you the actual lyophilization curve, not just a claim that "our freeze-drying is thorough."

3. Moisture and Aw: Both Matter

Many brands only test moisture content (usually ≤ 5%). The standard is more concerned with **water activity**, which predicts microbial growth and shelf life beyond 18 months:

• Moisture ≤ 5%;
• Water activity Aw ≤ 0.60;
• Both tested on every outgoing lot.

4. Rehydration: ≥90% Within 3 Minutes

Whether freeze-dried pieces can substitute raw or stand in for fresh food depends on rehydration:

• In 25°C water, ≥90% rehydration within 3 minutes;
• No obvious sediment, no oil separation after rehydration.

This is the hidden weak point. The freeze dryer is easy to buy; the curve is hard to tune. Poorly tuned pieces rehydrate into mush.

5. Hygiene: Total Count, Coliforms, Salmonella

Hard indicators retained from pet feed hygiene rules:

• Total plate count ≤ 100,000 CFU/g;
• Coliforms ≤ 100 CFU/g;
• Salmonella absent;
• Moisture ≤ 5%.

The co-packer must supply **lot-level outgoing test reports**, not just an annual type-test report.

6. Labeling: Do Not Write "Raw Freeze-Dried" Casually

Key labeling changes:

• Do not loosely write "freeze-dried raw meat" unless the product also meets raw food requirements;
• The standard category is "freeze-dried pet food";
• Ingredient names must follow the feed catalog;
• Drying method (vacuum freeze-drying) and storage conditions must be declared.

Closing

Freeze-dried is booming, but post-standard the competition is no longer "who can do freeze-dried"—it is "who can do it consistently to the standard." Ingredient traceability, process curves, Aw, rehydration, hygiene and labeling should be locked at sampling.

> Brands evaluating freeze-dried can contact **Mixiaoqi pet food OEM/ODM** (Mixiaoqi Guangzhou Pet Technology Co., Ltd.). We sample to the full NY/T 4839 checklist, with lot-level process curves and outgoing test reports.