Food

Controlled production, packaging, transportation and storage processes are essential to produce high-quality and healthy food

Humidity

Importance of humidity control in food processing:

1. Prevent condensation on the product or processing equipment leading to excess moisture in or on the product or it’s container. The presence of moisture can lead to:

• blockages in machines and within pneumatic conveying systems
• slower processing due to slower transport speeds
• issues with packaging operations, for example, clumping of powdered or granular products, labels not adhering to bottles and paper-based packaging absorbing moisture.
• quality issues
• shortening of shelf life through bacterial and fungal growth

2. Reduce the production time of foods that would traditionally be dried naturally, e.g. cured meats.

3. Ensure optimum humidity levels are maintained throughout the stages of production to guarantee the quality of final product, in terms of flavour, aroma and texture, this is particularly relevant to baked goods.

Optimal humidity conditions for packaging, transportation and storage:

As with food production processes, packaging humidity requirements vary according to the product; cracker and wafer packaging is carried out at 35-40 %RH compared to 20 %RH for instant coffee.

Humidity control is vital in transportation and storage of fresh fruit and vegetables.  If the humidity is too low, water loss will occur resulting in mould and decay.  Fruit generally requires lower humidity conditions than vegetables.

If conditions aren’t controlled process efficiency, output, and product quality are impacted resulting in lower profitability.

Temperature

Maintaining a low temperature when producing, packaging, transporting, and storing food is essential to food safety in preventing bacterial growth and toxin formation.

Temperature can frequently be measured using the same device as that used to measure humidity.

Air flow and differential pressure

Food production facilities require a good air flow design to achieve effective removal of contaminants via filtration, pressurisation and temperature and humidity control.

Air velocity meters need to measure reliably at 0.12 – 0.26 m/s to ensure that filters aren’t blocked, and that good air flow persists.

A positive air pressure needs to be maintained between food production areas and outside and a pressure gradient needs to be maintained between raw foods and finished products to prevent cross contamination.  Differential pressure sensors can be used in addition to air flow sensors for monitoring and control.

Another application for air velocity sensors is in the freezing of food. Increased air velocity effects faster freezing times.

Uses of gas in food in the food supply chain

In food production

Liquid nitrogen and CO2 are used in production processes such as the grinding of nutraceuticals, spices, and other ingredients to prevent frictional heat and to retain the organoleptic characteristics, namely flavouring, aroma, colour and appearance characteristics of products.

In transportation and storage

Monitoring and controlling the concentration of gases in the ripening of some fruit is key to ensuring it is in top selling condition when it is bought to market as it is preserved in a protective atmosphere from the time it is picked to delivery to its destination, be it a restaurant or a store. The ripening process is moderated through controlling the concentration of CO2, C2H4 (ethene) and O2 in the atmosphere together with temperature. C2H4 is a plant hormone exuded by various ripe fruits e.g., apples, bananas, and tomatoes which in turn stimulates the ripening of unripe fruits. If fruits are harvested before they ripen and are refrigerated, the ripening process will be interrupted. Once brought out of refrigeration they are exposed to a concentration of ethylene between 100-1000 ppm and specific CO2 and O2 concentrations to control the rate of ripening.

Food packaging

Oxygen, carbon dioxide and nitrogen are used solely or as a mixture to extend shelf life and     prevent degradation of many packaged foods… e..g. meat products, dairy and bakery products.  Removal of the air from the product package and replacing it with a gas, or a gas mixture is known as Modified atmosphere packaging (MAP).  Residual oxygen content is typically below 2%, this can be checked by means of a MAP analyser which will use an oxygen sensor to measure the concentration in the packaging head space.

Oxygen sensors with lead will be banned under Restriction of Hazardous Substances (RoHS) legislation from 2024 so will shortly be replaced by lead free electrochemical sensors. Omni Sensors and Transmitters Figaro KE25-LF series will succeed the KE25 series, the sensors will not only meet the lead free RoHS requirements but will excel amongst other oxygen electrochemical sensors in terms of selectivity to oxygen in the presence of CO2 as the KE25 series does. Furthermore, Figaro have recently released a new lower cost TGS 4260 Oxygen sensor for use in oxygen deficiency monitors to check the atmosphere is safe for operators in inert gas food storage areas, fruit transport and storage, breweries and other food and beverage production areas

Omni Sensors supplies a range of NDIR CO2 sensor modules which can be integrated into an analyser, CO2 probes and CO2 room transmitters.  The CO2 modules and probes contain high performance, accurate, stable reliable dual wavelength CO2 sensors which outperform single wavelength sensors using ABC (automatic background correction) logic in terms of measurement accuracy and stability.

Refrigerant gases are also used indirectly in the food supply chain to chill and freeze foods.  Omni Sensors and Transmitters supply a range of sensors and pre-calibrated modules and transmitters for leak detection. F gas guidance

Moisture content of food powders and grains

Food production processes that involve drying, roasting or frying require rapid moisture analysis of the product during processing in order to optimise processing.  An example of such a process is coffee bean roasting. An unprocessed, ripe coffee bean should contain around 45–55% moisture.  Processing and drying will then take its moisture content down to 10–12%. During the roasting process, the free moisture will evaporate first and at a later stage, the bound moisture will evaporate. Moisture affects the duration of a roast; beans with a moisture content of less than 10 percent will roast much faster owing to reduced free moisture content. In this case, the roaster operator needs to change the roasting profile by charging the beans at a lower heat level and maintain a lower amount of energy supply during the first roasting phase.

Fresh crop coffee beans typically have a high moisture content of > 14%.  In this instance the roaster operator will include a pre-drying phase before starting the first phase of roasting.

Moisture content and water activity are important parameters in both raw and baked goods, e.g. fruit, mushrooms, flour, granulates and biscuits. Levels impact both the quality and the shelf life of the product.

Omni Sensors supplies a range of capacitive and near infrared moisture analysers which provide instantaneous moisture and water activity measurements.

Omnisensors and transmitters offer a range of sensors and transmitters for use across the food supply chain. 

Humidity and Dew point: EE072 Humidity and Temperature Probe with Sigma 05 modular platform, EE310 High-end humidity and temperature sensor up to 180 °C, EE220 Humidity and Temperature Transmitter with Interchangeable Probes.

Temperature: EE074 Temperature Probe with Modbus RTU and Sigma 5 platform, EE220 Humidity and Temperature Transmitter with Interchangeable Probes, EE300Ex-M3 Intrinsically Safe Temperature Transmitter,

Air velocity and mass flow:  EE576 compact air velocity probe, EE660 low velocity air flow sensor

Pressure: EE600, PU/PI, PS 27, PS17, P26, P34 differential pressure sensors

Gas sensors: EE 895 and EE 894 CO2 sensor modules, EE 850 duct mount CO2 transmitter, EE 820 CO2 transmitter, EE872 CO2 probe + Sigma 05 platform, CO2 Flow evo, CO2 basic evo module, CO2 evo transmitter,  Ethylene Flow Evo, PAS ethylene sensor, Anarex fruit storage sensor, KE25, KE50 and KE12 O2 sensor, KE-LF series O2 sensor, SK25F O2 sensor,  Refrigerant gas sensors; TGS 2630, 3830 and 832

Wireless monitoring control solutions: e.gs EE 242 base station, EE244 modular wireless transmitter + EE872/EE07/EE03 for various combinations of humidity, temperature and CO2, EE245 room transmitter

Aranet wireless CO2 sensor + Aranet Pro base stn

Aranet Wireless temperature sensors: Aranet T Compact, Aranet T/RH, Aranet T/RH IP67, Aranet T/RH probe, Aranet t-probe, Aranet PT100 sensor, Aranet PT100 transmitter, Aranet PT1000, 0-10V and 4-20mA transmitter

Moisture meters-application specific: FSA automatic grain analyser,  FS3 coffee moisture meter,  FSG food analyser RH2 water activity meter

Why use Omni Sensors?

Omnisensors and Transmitters, located near Leamington Spa, England provides friendly support, product advice and ensures timely delivery.  We supply quality designed and engineered sensors.