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Food Safety Focus (146th Issue, September 2018) – Incident in Focus

Control for Safe Delivered Foods

Reported by Dr Ken CHONG, Scientific Officer,
Risk Communication Section, Centre for Food Safety

Background

Two food poisoning clusters involving customers consuming delivered food prepared from the same premises were reported in July 2018.  In recent years, food ordering mobile apps are getting more popular.  Comparing with traditional way of ordering, customers can make food orders from premises in a wider area through the apps and the courier service provided by the app companies. 

Food Safety Risk of Delivered Foods

Under this operation of delivery service, comparing with traditional delivery, prepared foods may need to wait longer as delivery persons have to pick up foods from premises.  In some cases, delivered foods may be purchased in bulk and delivered in insulation containers to an open area for picking up by individual customers.  These may result in additional time in delivery and/or distribution.  Delivered meals are usually perishable foods.  If there is improper time temperature control during delivery, microorganisms including pathogen that may be present in foods can grow rapidly to a large number and make people sick.  Indeed, similar to traditional way of ordering, delivering foods without time or temperature control can increase food safety risk.  As such, proper time temperature control is important to address the potential food safety risk arising from delivered meals.

Example on keeping time for ordering by mobile apps.

Time Temperature Control for Safe Delivered Foods

Keeping hot food hot and cold food cold, i.e. above 60°C and at/below 4°C respectively, can keep delivered foods safe.  Most pathogenic bacteria grow and multiply rapidly at temperatures between 4°C and 60°C.  This range of temperatures is therefore called the “temperature danger zone”.  Delivered foods can be maintained out of this danger zone by ways such as using insulated containers, keeping foods in a warmer or cooler before delivery, and avoiding preparing food too early, etc.
Under the time-temperature contral for food safety, if foods are delivered within the temperature danger zone, time control in advance will become the only gatekeeper. There are two time limits, two-hour and four-hour, for keeping perishable foods: 

Time within Temperature Danger Zone

The time for foods being kept within the temperature danger zone is cumulative, i.e. it is needed to add up each and every time period that the foods have been left under ambient temperature, including handling, storage, transportation, etc. (See figure).  Individual ready-to-eat ingredient may be prepared in advance and left under ambient temperature before serving.  If there is no further processing or other means to control the growth of microorganisms, the time that the ingredients have been left under the temperature danger zone should be added up to work out the total time under the two-hour and four-hour principle.  As such, for food delivery, both food handlers and delivery persons have to work out the arrangement together to fulfill time temperature control requirements to ensure food safety.

Key Points to Note:

1.  Delivered meals are usually perishable foods.  Microorganisms that may be present in foods can grow rapidly to a large number and make people sick if there is improper time temperature control during delivery.  
2. Keep hot food hot and cold food cold for safe delivered foods (i.e. above 60°C and at/below 4°C respectively). If not, the two-hour and four-hour principle should be followed for perishable foods that have been kept in the temperature danger zone.
3.  Add up all time periods that the foods, including individual ingredients, have been left under the temperature danger zone to work out the total time

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