Never heard of a manufacturing facility having separate storage conditions of 4degC and 5degC. How did you operationally achieve such a minute difference ? I rather doubt most systems could consistently measure it.
Pasteurization for eggs afaik is typically targeted for safety at a specific bacterial species (eg Salmonella). From memory egg is (not surprisingly) sensitive quality-wise to the maximum temperature. Some pathogenic spores (and theoretically some veg. species) can survive Salmonella pasteurization hence chilled storage.
The precise storage temp. for safe chilling storage varies with textbook/location/author. Most hover around 4-5degC which in practice is usually implemented as a limit, eg < 5degC. Some pathogenic bacteria can grow below this, eg L.monocytogenes.
In UK, from memory, home storage chilled refrigerator sections are regulatory limited to max. 8degC although recommended to target 5degC. A reflection of practical control capability. Australia no idea.
PS - just saw the previous post. No personal experience with eggs so my comments were not specific to liquid egg, maybe this form has some particular risk factor / Local Regulatory requirements which require freezing. Maybe simply a shelf-life criterion.
PPS - here are USDA requirements (maybe different process conditions to Australia) -
Safe Handling and Storage of Egg Products
Safe handling and storage is necessary for all egg products to prevent bacterial contamination. Here are recommendations from USDA:
- For best quality, store frozen egg products up to one year. Check to be sure your freezer is set at 0 °F or lower. After thawing, do not refreeze.
- Thaw frozen egg products in the refrigerator or under cold running water. DO NOT THAW ON THE COUNTER.
- If the container for liquid products bears a "use-by" date, observe it. Follow the storage and handling instructions provided by the manufacturer.
- For liquid products without an expiration date, store unopened containers at 40 °F or below for up to 7 days (not to exceed 3 days after opening). Do not freeze opened cartons of liquid egg products.
- Unopened dried egg products and egg white solids can be stored at room temperature as long as they are kept cool and dry. After opening, store in the refrigerator.
- Reconstituted egg products should be used immediately or refrigerated and used that day.
- USDA Commodity Dried Egg Mix should be stored at less than 50 °F, preferably in the refrigerator (at 40 °F or below). After opening, use within 7 to 10 days. Reconstitute only the amount needed at one time. Use reconstituted egg mix immediately or refrigerate and use within 1 hour.
40degF = 4.4 degC
50degF = 10 degC