Smokehouses are used for heat treatment and to add flavor, color, and aroma to various food products, including pork, beef, sausages, poultry, fish and cheese. A typical process will include most or all of the following steps
- Colors set
Chamber temperature, product temperature, relative humidity (RH%) and calculation of Po-values are critical parameters for smokehouse processing.
The two types of smokehouses are batch and continuous smokehouses. Both types of systems circulate air at the desired process conditions (temperature, humidity, and smoke density) over the surface of the products.
Batch Cooking-Smoking Chambers
Commercial chambers, mostly made from stainless steel, have independent systems for smoke generation and cooking. Smoke generators either using wood smoke or liquid smoke are typically used. Gas, Steam and Electrical Systems are the most common heat sources for ovens. Elaborate air handling systems reduce hot or cold spots, to reduce variation in the finished product. Racks on wheels or rails are used to hold the product and facilitate movement.
Continuous Cooking-Smoking-Chilling Tunnels
In continuous smokehouses, the meat is hung on sticks or hangers and then conveyed through the various zones (smoking, heating, and chilling) within the smokehouse. Following processing in the smokehouse, the product is packaged and stored for shipment. Validation of these can only be performed with TrackSense wireless data loggers.
Temperature Distribution Test
The test is designed to ensure that the chamber is at a uniform temperature and the test must be designed to locate the slowest heating area in the chamber (cold spot).
Once the slowest heating area is located the test probes should be concentrated in that area to determine the parameters required bringing that area of the chamber to a uniform temperature.
New chambers will need temperature distribution studies and chambers that have undergone repairs or redesign also. It is also mandatory to retest existing chambers at a reasonable frequency e.g. every 3 years.
Temperature distribution tests should be performed in each individual chamber both empty and fully loaded
The complex air flows in smoking chambers means that heat transfer is likely to be both temperature and flow rate dependent, so heat distribution testing should be considered with double sensors at the same location, one measuring product heating and the other the local environment temperature.
Heat Penetration Test
The purpose of heat penetration test is to determine the heating and cooling behavior of the product in a specific chamber for establishment of a safe thermal process and evaluating process deviations, to find the “cold spot” in the product, and to ensure that all products receive the required heat.
A Temperature Distribution Test should be completed before commencing the Heat Penetration Test. The goal in conducting these tests is to identify the worst case temperature response expected to occur in commercial production as influenced by the product and the process parameters.
Validation of continuous smokehouses can only be performed with TrackSense® wireless data loggers.
In the Food Industry today many smoked meat products are produced every day using different processing parameters, resulting in development of products with unique identities, but there are several critical factors that have to be monitored and evaluated periodically:
- Acceptable Heat in the chamber affecting the safety and quality of the products
- Accurate temperature measurement system such as E-Val™ Pro & TrackSense® Pro
- Po-Value calculations of the product
- Relative humidity measurements (RH%) affecting the color, texture, skin adhesion, no over drying and the appearance of the products
- RH% measurements using dry/wet bulb technique (psychrometric)
- Validation of continuous cookers can only be performed with TrackSense wireless data loggers.
Failure to measure at the “cold spot” of the product is a major source of error, and therefore a wide range of fittings securing reproducibility for every batch is available.
Before doing any measurements, it is a good idea to use equipment which is complying to:
- ISO 9001 Certification
- FDA 21 CFR 123 & 21 CFR 110
- 21 CFR part 11 Electronic Signatures
- CE & UL Approvals
- cGMP or GAMP
- ISO/IEC 12207 Software life cycle processes
- Guidelines issued by local authorities
Recommended Test Equipment
- The calibrated system should be equipped with sufficient channels to accurately monitor and record temperature and RH% within the process delivery system.
- Use thermocouples or other devices of sufficient accuracy in sufficient quantity to adequately monitor the process temperatures within the chamber.
- The chamber MIG/ETI must conform to applicable regulations and shall have been checked for accuracy against a certified TMD within the past year, preferably more recently.
- The data logger should record the temperatures and RH% of each sensor at sufficient intervals, not to exceed one minute, throughout the test.
- Prior to the actual temperature distribution study, standardization or calibration should be performed in the test chamber if using a cable system.
- One method of calibration is to bundle all sensors and locate them in close proximity to the known MIG or ETI if using a cable system.
- Check the accuracy of the sensors against the reference instrument (ETI). Any single sensor should be within 0.3°C of the reference.
- The maximum deviation between any of the sensors should not exceed 0.6°C.
- Initial temperature should be recorded
- A sufficient amount of temperature sensors are typically positioned in the corners and the middle of the chamber.
- During heat penetration tests the temperature sensors are positioned in the “cold spot(s)” detected by the temperature distribution tests.
- Product temperature sensors are typically positioned in the center of the product (“cold spot”).
- Use two temperature sensors for dry/wet measurements for calculation of the RH%.
- Bring the chamber up to the same temperature as designed for the actual process and allow temperature to equilibrate.
Choosing the System
A thermocouple system like E-Val™ Pro has the advantage of always showing data in real-time, but it can be time consuming to install the thermocouple probes and they could get damaged during loading and unloading.
A wireless data logging system like TrackSense® Pro is logging the data which after the process are downloaded to the computer. This is easier and faster to install in the chamber. To have real time measurements a TrackSense® SKY system is used. Another advantage using the TrackSense® Systems is the capability of using dual sensors, so that Temperature Distribution and Heat Penetration measurements can be performed simultaneously.
To validate the processes according to the predefined acceptance criteria’s the ValSuite™ software is used.
Documentation – Standard ValSuite™ Reports
- Comments: Specifications and test equipment
- Limit Report: Temperature, RH%, Po-Values
- Time Event Markers: Conditioning, Drying, Smoking, Color set, Cook, Chilling
- Advanced Validation Report: Temperature, RH%, Po-Value evaluation of the whole process criteria’s with pass/fail indication
- Statistic Reports: Min, Max, Average, Delta of all parameters
- Word Documents