Food manufacturing processes are increasingly making use of temperature profiling methods. Food suppliers use oven dataloggers to perform process monitoring and testing programs in the development of reliable quality assurance procedures. Of course, the goals in processing these products are to ensure presentation and cooking time consistency. Accomplishing these goals first requires a significant amount of research to establish exactly what is happening inside the industrial oven during the heat processing such as the heat distribution.
In the processing of nut products, for example, oven temperature dataloggers are used for both oil and dry roasting, where they continually monitor and verify roaster temperatures. In recent years, food product recalls have raised awareness of health hazards such as salmonella in almonds, pistachios and peanut butter. These have prompted industry-wide use of temperature monitoring devices to verify equipment and thermal remediation processes to reduce microorganisms. Given that any existing salmonella likely has already dried on nut products before they reach the thermal processing stage, the bacteria are incredibly resistant to heat. Furthermore, different types of nuts vary widely as to the method and variation of heat to apply, and not all heat treatment methods ensure the same result.
Roasting potatoes is another example of a food processing application that requires iterative profiling to find the proper heat treatment process. In practice, it can be difficult to reproduce a crisp quality product. This lack of uniform temperatures or a single process methodology across companies means that the industry cannot take product quality for granted.
In search of effective heat treatment methodology, processors often undertake a series of oven temperature profiling exercises in order to measure oven performance and see if their product is reaching the correct core temperatures during the process. Additionally, workers also need to view other factors such as the ambient air temperatures around the oven. Due to the way that many ovens are loaded, there exists a complex movement of hot air inside, resulting in both high- and low-temperature spots.
To undertake a quantitative analysis of their processes, a datalogging solution is required. However, because many temperature recorders exist for this purpose, it can make the initial research stage intimidating. Among the types of loggers typically used in heat treatment applications in food processing are oven temperature dataloggers, USB thermocouple dataloggers, wireless dataloggers and handheld data collectors.
Oven Temperature Dataloggers
These temperature profiling devices are placed in a stainless steel thermal barrier, which protects the electronics during their exposure to the high oven temperatures. The datalogger, inside its thermal barrier, enters the oven along with the roasting product. In this way, users can monitor the process temperature from several different points and view any combination of air, tray and product temperatures. Fast-response and high-accuracy probes are available along with models capable of taking the necessary surface and air temperature measurements.
USB Thermocouple Dataloggers
Less specialized USB dataloggers also are available for those just needing a quick solution for thermocouple connection without extensive functionality. USB thermocouple dataloggers interface with various thermocouple types — commonly one per temperature point — and an enclosure is necessary. Often, the dataloggers can connect with many different styles of Type K thermocouples to monitor extreme temperature ranges, supporting high sample rates. Typically, the data is gathered by removing the dataloggers from each oven and taking them to a computer to interface via USB ports.
Thermocouple dataloggers utilizing wireless communication capabilities form a user-friendly solution to manage the temperature data. A common setup incorporates one logger per temperature point: the wireless thermocouple units accept one thermocouple each and will record data at any desired interval, from once a second to once an hour.
Whether wired, USB or wireless, some datalogging devices store data but require the use of temporary data cards, which need replacement over time. To get around this, some dataloggers are available that can store up to 250,000 temperature readings for extended logging. Several communications options exist, including a USB communication cable to communicate with a PC for quick setup and download of stored data. Some models also include a long-life battery option for years of extended operation as opposed to a standard battery.
Handheld Data Collectors and Datapads
Portable data collectors and datapads are another option for users to streamline data gathering and accessibility. The temperature data is gathered by using the handheld collector at the oven to plug the unit into and extract the data. It then can be transported to a computer, eliminating the need to purchase memory cards. Data also can be collected remotely using wireless loggers and collectors. This allows continual logging with shorter breaks in data collection, less travel for the user, on-site data collection in graph, legend and summary format, and the ability for users to reconfigure loggers in the field.
The companion handheld collector links wirelessly to its compatible dataloggers for real-time monitoring and data download. Instead of having to walk up to a datalogger to read the temperature and bring each to a PC, the information is shown on the spot and stored on the data collector. With these devices — many of which use touchscreens — users can name their logger, select a sample rate, set high and low alarms, and choose the logging start time. Data then is collected by the loggers and downloaded to the computer via a micro USB cable.
By making upper and lower limit settings on the collector, users are able to easily monitor the recorded data in real time for irregularities such as a rapidly decreasing or uneven temperature. Once uploaded, data is saved in comma separated variable (.csv) format, making it suitable for import into spreadsheet packages such as Microsoft Excel or graphed on a PC.
Many different software choices exist, either sold separately from the logger or included with it. Many utilize a spreadsheet-style package that eases setup and automatic data download. Users also can get graphic analysis of historical and online data along with advanced reporting. Datalogger status is viewed and controlled from a single screen, with all settings savable for reuse, and security functions are available to protect all data and setup configurations. Graphing and charting capabilities can give detailed analysis of the temperature profile, and users can build entire databases containing data exported into Excel or as a .csv file for customizable data analysis.
Installation of an oven datalogger or another automated datalogging solution allows factories and plants to collect and analyze critical process temperature data at high accuracy. For example, now users are able to experiment with different strategically placed baffles that redirect airflow and to try out different layout and loading of their product on trays, helping to improve product quality. This trial and error is easily verifiable — after each change, the temperature is logged and the data downloaded onto a PC for detailed analysis using the software.
Once a process has been optimized by configuring parameters such as oven temperature, airflow, product location and other parameters, production can be confidently increased. To maintain the right consistency from this point onward, users can carry out periodic checks with their dataloggers to ensure that quality control and batch-to-batch productivity are maintained.