Rejection systems are critical to quality control in food processing. These fault detection systems quickly check products for contaminants, weight, missing components, and defective packaging, ensuring consumer safety and satisfaction.
Before food reaches the consumer, automated rejection mechanisms at the production stage can prevent food waste when distributors refuse a product. ReFED estimates that 2% of prepared foods are rejected by buyers, so managing the quality of food products before they leave manufacturing can significantly impact the amount of food waste produced.
Without accurate rejection systems, it is easier for contaminated products to reach consumers even with extensive contaminant removal efforts. When this happens, consumers are at risk of illness or injury from ingesting impurities such as metal components or hazardous chemicals. These incidents are incredibly dangerous and leave production sites vulnerable to recalls, serious legal action, and reputational damage.
By investing in efficient rejection systems, food manufacturing sites can protect consumers and themselves from harm and expensive consequences that may hinder future sales.
The Purpose of Rejection Systems
Rejection systems help to maintain high standards of food quality and operational efficiency, as these automated tools offer greater accuracy and speed than can be achieved when solely relying on human inspections. These systems make it easier to comply with federal food safety regulations set out by organizations such as the FDA, USDA, and BISSC, which each mandate specific quality control measures to safeguard consumers.
These systems prevent contaminated or defective products from reaching the marketplace, which is a vital safeguard of consumers’ health and safety. Thorough inspections can prevent the need to recall faulty products, which protects brands’ reputations and improves consumer trust. Consumers can be wary about purchasing products from brands that undergo a recall for safety reasons, and this can significantly impact brands’ sales and customer loyalty moving forward.
Avoiding recalls through automatic rejection services can help prevent financial losses and keep consumers safe.
Types of Rejection Systems in Food Processing
There is a range of automated rejection systems available for different products. The mechanism varies depending on the weight, size, and type of food product in question.
Air Blast Systems
Air blast rejection systems are common choices for lightweight packaged products. These mechanisms work by using a small nozzle connected to a pressurized tank to deliver a sharp burst of air that knocks a product out of the assembly line when contamination is present. Supervisors can adjust the air pressure of these systems to ensure precision (preventing other non-contaminated items from flying off the belt) and suit different item weights.
These systems are not ideal for heavier items or those that may be damaged and create a mess when the air blast strikes them.
Stop-on-Detect Systems
One automated rejection option that does not remove the item from production is a stop-on-detect system. This system simply halts the production line upon contamination discovery without ejecting the item from the line. These systems work best for heavy or awkwardly shaped products that can be difficult to remove once the line starts. However, stop-on-detect tools can slow production speed in manufacturing environments where contamination occurs more frequently.
Pusher Systems
Another option for removing rejected products is pusher arms. As with the air blasts, these mechanical paddles gently push rejected items off the production belt toward a collection area without stopping production. This is a good option for midweight items like loaves of bread and other packaged goods.
Retracting Conveyor Systems
Retracting conveyor systems are a popular choice for sturdy products and produce. They involve a retracting section of a conveyor belt that allows faulty products to fall into a bin below or onto a second, lower conveyor belt for further inspection and disposal.
Timing the retraction precisely can be difficult, but once the system is fine-tuned, these are great choices for fast-paced environments where entirely stopping the production line would be inefficient and costly.
Diverter Arms and Gates
Some production lines rely on conveyor belt diverter arms and gates to direct contaminated products to different conveyor paths. These systems can sort products into multiple sections and reject products, making it possible for manufacturers to organize rejections based on type and even correct certain rejection-triggering issues, like missing packaging, to reduce waste.
Pneumatic Reject Actuator
A pneumatic reject actuator responds to an X-ray or other scans that indicate a contaminated product. These systems then use gentle air pressure or a small paddle to push rejected products off the production line. This option is gentler and more precise than simple air blasts, making it a great choice for fragile products.
Integrating Vision Inspection Systems
New developments in camera and sensor technology have led to improvements inproduction vision inspection systems. These tools offer manufacturers better detection capabilities and allow them to automatically identify indicators of poor quality, such as color inconsistencies and irregularities in the size or shape of a product. These systems also include scanning mechanisms like X-rays to detect solid contaminants.
These emerging fault detection systems can be easily integrated with the above rejection mechanisms so that any product with suspected contamination automatically passes through the product ejection unit (or causes the line to stop, depending on the product). These systems also offer data analysis and storage, allowing supervisors to view real-time analytics and compare them to historical data. The precise data analysis can make it easier to enhance quality control and prevent false rejections.
Common Rejection Triggers in Food Processing
Food products may trigger manufacturing rejections during the inspection process for various reasons. The primary goal is always to reduce contamination in the end product, keeping customers safe and preventing costly recalls. Metal detectors and X-rays assess for metal contamination and other solid, foreign bodies.
Rejections may also occur due to weight discrepancies, particularly in dairy and similar products, where an item’s shelf life depends on its precise weight and volume. These weight rejections ensure consumer safety and keep serving sizes consistent.
Another potential trigger is packaging issues such as incorrect labels, missing caps, or broken seals. Barcode or failed print verification can also lead to rejections, as thesecan cause issues for the buyer and distributor. Finally, product deformities, including color and shape issues, can also be causes for rejection, as is often the trigger for rejected produce.
Technical Considerations for Effective Rejection
Manufacturers must consider the size and speed of their production lines when choosing an effective rejection mechanism. The size and speed of the belt itself can render certain rejection options useless. Product characteristics such as size, weight, and shape also play a role in determining which automatic line ejection methods are best.
The right automated rejection system also depends on the shape and layout of your facility, as larger mechanisms may not be suitable for tightly packed spaces.
Finally, production managers must consider the hygienic design requirements for the rejection systems that handle food. Non-contact mechanisms, such as air blasts, may be best for non-packaged foods.
Industry-Specific Applications
Manufacturers must also choose their rejection mechanisms based on their industry. For instance, bakery products, packaged goods, and beverages tend to suit push mechanisms, while meat and poultry items may require diversion gates.
Dairy products should consider incorporating weigh scales and either push paddles or retracting belts. Lightweight confectionery items are often compatible with air blasts and pneumatic ejections.
Benefits of Advanced Rejection Systems
Advanced rejection systems save manufacturers money by reducing food waste and minimizing redundant production costs. These automated systems also increase output and efficiency, especially if you implement automated solutions that don’t necessitate stoppages. Careful screenings ensure food safety and quality, making compliance with federal regulations easier.
The data collection and analysis involved in automated rejection systems also contribute to process improvements, fewer false rejections, and enhanced quality control.
Challenges and Solutions
Automated rejection systems are not without their drawbacks. First, high-speed production lines may find these processes slow their manufacturing (especially when detections lead to stopped belts). However, the increased efficiency of not relying solely on manual checks tends to make any delays or stops worth it.
Additionally, some production sites that manufacture a variety of products on the same line may struggle to implement rejection mechanisms. It is possible to use several rejection mechanisms on the same line and divert products between them to maintain quality control efforts. The clean-in-place requirements for rejection mechanisms can also be challenging, but are manageable for production sites with established, rigorous sanitation standards.
Some are concerned about the need to balance detection sensitivity with productivity. This balance is achievable with careful tuning and trial and error testing, which a professional can assist with during installation.
Finally, some fear the challenge of integrating these tools with existing systems, and for those manufacturers, a custom solution often produces the best results. By having an expert assess your facility’s needs and tailor a solution for your business, you can easily integrate these systems into your production line.
Future Trends in Food Processing Rejection Systems
As food processing rejection systems develop, manufacturers can expect to see an increase in AI and machine learning integration with the current data analysis systems. Rejection systems will continue to become more adaptable, creating Smart inspection mechanisms. These systems will also become more sustainable as technology shifts to reflect growing climate concerns.
Additionally, while some models already offer this, more rejection systems will allow for remote monitoring and control. Smarter systems may offer predictive maintenance reminders that prevent major repairs and save manufacturers money in the long term.
Choosing the Right Rejection System
When choosing a rejection system, manufacturers should consider their site’s specific needs. These specifications include things like the size and weight of the products, the layout of the facility, and the rate of production. It can be helpful to consult experts about the potential for custom solutions.
Working with a provider willing to tailor the rejection mechanisms allows production sites to create flexible systems that work for various products and streamline the installation and calibration processes to maximize efficiency.
Production sites should also consider the ROI for these systems and evaluate the cost of initial setup against the money saved by avoiding recalls and reducing the need for staff to conduct manual inspections. While the initial investment can seem intimidating, it is almost always worth it compared to the lasting consequences of a consumer safety incident or quality recall, which can tarnish brand reputation and lead to major delays in production while diminishing future sales.
Lastly, manufacturers should understand the implementation timeline and training requirements for new rejection systems. Working with experts to customize and install these systems may speed up the timeline and provide training guidance that streamlines employees’ transition experience.
Overall, investing in automated rejection systems is critical to protecting consumer safety and maintaining regulatory compliance. These mechanisms efficiently enhance food safety and quality control without interfering with productivity, ultimately saving manufacturers money by preventing recalls and other costly consequences of contaminated or inferior products.
Manufacturers should learn how rejection systems work in food processing and consider implementing these systems to boost efficiency, safety, and compliance. Let TDI Packsys help with installation, training, and maintenance.
