Kitchen equipment advice (commercial)

Commercial kitchen equipment maintenance

Regular maintenance and good hygience practice can help keep your kitchen equipment safe and in good working order.

Fridges 

• Follow the manufacturer's instructions
• Do not put it next to a source of heat 
• Use a fridge thermometer and keep food below 8°C
• A packed fridge will not work as well as one which allows air movement
• Keep dry foods at the top
• Keep cooked meats or foods that are ready to eat in the middle
• Keep food that requires cooking, such as raw meat at the bottom
• Do not leave the door open for too long
• Clean the door seals with detergent and disinfectant to remove mould growth

Fridge breakdown

• Throw away spoiled food 
• Clean the inside of the fridge when the power has come back

Freezers

 

• Follow the manufacturer's instructions
• Follow instructions on food packaging
• Keep the temperature of the freezer between minus 18°C and minus 22°C 
• Label food packaging and containers with date of cooked and use-by dates
• A well-stocked freezer is more energy efficient
• Do not allow ice to build up inside freezers
• Defrost freezer units by following manufacturer's instructions

Freezer breakdown

• Keep the doors shut and keep air vents clear
• If raw food still has ice crystals and has not been exposed to any contamination you can refreeze it provided the temperature has not reached above -3°C (if higher cook the food straight away or throw it away)
• Ready to eat food with no ice crystals should be thrown (if ice crystals are present and there has been no risk of contamination, and the temperature is lower than -3°C, then you can eat the food, following the preparation and cooking instructions)
• Clean the inside of the freezer, removing food debris, once the power comes back

If a power failure lasts for more than 8 hours throw away the food.

Microwave cooking

Keep your microwave oven clean:

• Cleaning with a detergent and disinfectant will remove dirt and reduce bacteria that have built up - this will ensure that your microwave works efficiently
• Check your microwave manual for recommended cleaning products and methods
• Only use utensils and containers that have been approved for microwave use - poor use may result in damaging the microwave oven, or making the food unsafe

Cook food properly:

• Heat leftovers and pre-cooked food to at least 70°C - food should be very hot and steaming
• Liquids containing meats (like casseroles and stews) must be boiled for roughly five minutes to ensure the pieces of meat are heated through
• Stir things halfway through cooking to avoid cold spots
• Cook food for the minimum time recommended, then test for thorough cooking - juices in chicken, beef, pork and fish should run clear

Ice machines

 

• Connect your machine directly to a mains water supply
• Keep it in an area free from dirt and dust, ideally off the ground and in a position which provides ventilation and easy access
• Service the machine following the manufacturer's instructions
• Remove dust, grime and limescale regularly
• Clean all ice handling equipment, such as buckets and tongs or spoons, regularly throughout the day
• Do not allow ice to be transferred by hand - train staff in proper handling procedures
• Do not store bottles, cans or glasses in the ice intended for human consumption
• Ensure scoop handles are not in contact with ice

Vacuum-packing machines

• Follow the manufacturer’s guidance and service it regularly
• Change the oil as necessary
• Regularly check seals and replace them if they are damaged to prevent a poor vacuum
• Do not dual-use machines. If you use a vacuum packer for raw meat you can't use it next for ready-to-eat foods
• If you buy a second hand machine, check its history. If it was used for raw foods and you want to use for ready-to-eat foods, you will need to dismantle it for cleaning and disinfection

Packaging specifications for bags

• Make sure they are puncture proof
• Make sure they meet your temperature specification such as for sous-vide cooking
• Check that they are heat sealable
• Ensure they are suitable for food use

Shelf life of vacuum packed foods

• The spores of Clostridium and Bacillus species are heat resistant and grow in the absence of oxygen
• To prevent bacteria growth follow a maximum shelf life of 10 days for vacuum-packed products stored at 3-8°C
• A chilled shelf life of 10 days or more is permitted if one or more of the following are met:
  • pH of 5 or less throughout the product
  • Aw of 0.97 or less throughout the product
  • Heat treatment of 90°C for 10 minutes or equivalent throughout the product
  • Salt of 3.5% (aq) or greater throughout the product
  • Any combination of factors proven to inhibit growth or toxin production by C. botulinum

Read more about vacuum packed foods.

The Food Standards Agency offers free online training on vacuum packing.

Sous vide waterbath

Cleaning:

• Use potable water as heat transfer media
• Discard water and clean waterbath after every use
• If possible, put equipment through a hot dishwasher cycle 

Cooking:

• Sous vide or “under vacuum” processes commonly feature cooking at lower temperatures over extended periods than often found in commercial settings.
• If the process is defined as critical to food safety, then a suitable time/temperature combination must be achieved

The table below shows exerts of time/temperature controls for Listeria monocytogenes.

Temperature at the slowest heating point (°C)	Time (minimum)
60	43.48
65	9.30
70	2.00
75	26 seconds
80	26 seconds

The table below shows E.coli 0157 time/temperature controls.

Temperature (°C)	Time (minimum)
60	93 minutes
65	13.6 minutes
70	2 minutes
75	18 seconds
80	3 seconds

Calculating cooking time:

Time to waterbath equilibration + Time to thermal centre of product achieving cooking temperature + Desired cooking time = Total time a product should be placed in the waterbath

This could be done once for each recipe mimicking a “worst case scenario” and then checked using a calibrated temperature probe each time the product is prepared. 

When to do temperature measurements:

• At the start of the sous-vide to check water temperature
• At the start of cooking time to make sure thermal centre (the middle of the thickest part) of the product is at desired temperature
• During process to check water temperature
• Check thermal centre at end of process to confirm temperature has been maintained

All process temperatures should be measured at the thermal centre of the product. The coolest part of a product during cooking, usually the middle of the thickest part of the product. 

 Take into account:

• The time it takes for the water in the bath to reach the desired temperature after putting the product in the water
• How long it takes for the product to reach correct temperature at the core
• When checking the product temperature, you will need to use expanding foam tape and a needle nose thermometer to ensure bag integrity is maintained

Calibration:

• All instrumentation should be of sufficient accuracy and precision – minimum of ± 1°C, preferably ± 0.5°C
• Calibration frequency for working thermometers should be at least annually.
• Valid calibration certificates should be kept on file for all instrumentation used in the validation of heat-chill processes
• Boiling water vs. Iced water “Calibration” is not sufficient to accurately calibrate a needle nose probe thermometer.