Nadgoundi felt that while we are undergoing a transition from a traditional linear economy to a circular economy, increased focus is required on the food safety aspects.
“The food manufacturing chain involves sourcing, food processing, packaging, supply chain and ultimately the consumer. Ensuring food safety involves active involvement of all stakeholders. They need to implement good manufacturing practices and adopt a risk based approach,” said Nadgoundi.
He added, “A risk based approach involves assessment of risks under categories such as chemical, biological and physical. This is used to identify significant risks and its mitigation plan. Implementation of such a plan can lead to quantified food safety compliance for all involved in the food chain.
Nadgoundi gave examples of food manufacturing, and the risk assessment approaches which can be deployed. According to him, at the food manufacturer level, it is the responsibility of the brand owner to extend risk assessment to all the input sources that go into the formation of a food pack. And an integrated approach is important while doing this risk assessment.
“We need to understand that all these inputs are by the industry. They need to implement practices that ensure food safety compliance for their outputs which become inputs for making the food pack. After assessing the inputs, there is consideration of a manufacturing process like GMP. Then there is transit, storage and distribution which can also bring certain risks which needs to be assessed. The brand owners need to undertake stability and shelf life studies. This will involve predictive microbiology, predictive chemistry and predictive assessment of different storage and consumption conditions,” he said.
He also pointed out that one step down the line, we have the packaging converter. Their risk assessment would involve assessment of individual inputs which could be substrates such as aluminum, films, paper, glass, metal etc along with additives such as inks and adhesives. Then the GMP involved in converting these packaging needs to be thoroughly assessed.”
Food safety compliance for adhesives
Nadgoundi explained the safety compliance practices for adhesive manufacturers. He said “The adhesives used in flexible film laminates are bicomponent polyurethane adhesives. These adhesives rely on reactive chemistry to get the desired bond.”
Nadgoundi said, “When we look at manufacturing of adhesives, our risk based approach is extended to our inputs which involve polyols and monomers, solvents, reagents, catalysts and backbone modifiers. Then GMP compliant atmosphere is maintained to manufacture the food safe adhesives.
He added, “To assess the inputs, we do supplier qualification through audits and approvals. Then each lot is assessed by inward inspection. This provides us the confidence that we have consistent inputs and they result in consistent outputs. These collective considerations form our assurance of food safety.”
"While ensuring food safety, clear interpretation and identification of scope is very important. At times, we experience that query comes from end producer to converter and it is redirected straight to the adhesive manufacturer. The risk assessment requires a subject matter expertise and as adhesive manufacturer we many not know the risks associated with the substrates, inks or other additives that go in flexible laminates. Instead a logical approach with a supplier specific questionnaire is needed. For e.g. when we buy isocyanates, we use a supplier specific questionnaire to identify the risk associated with that input. The converter can do the same for each input in the laminate. Such a logical approach will help in a constructive manner to establish food safety compliance."
- Pravin Nadgoundi
Risk assessment approach for adhesives
According to Nadgoundi, Bicomponent adhesives present the risk of extended curing. When there is reactive chemistry active with associated film, paper or foil in the laminate, there is a significant risk of migration. This can impact the food components.
These bicomponent adhesives have a NCO and OH component. When they are mixed as per manufacturer’s recommendations the first reaction forms the polyurethane prepolymers. In the second phase, such prepolymers start reacting with atmospheric moisture to form extended chain of polymers. In physical terms this creates the desired bond to complete the laminate.
When we look at this chemistry, both stages of curing are important, the physical curing offers the desired initial tack to process laminates at the converters without the risk of delamination. The second phase which is chemical curing is extremely important from a food safety compliance point of view.
Nadgoundi mentioned, “Generally for the products that we are offering or are available in the industry, it takes 5-6 days for completion of the curing process. If the food processor starts using these laminates before the completion of curing process, there is a potential risk of aromatic amine formation which are carcinogenic in nature.”
Laminates should not be used for food processing unless both physical and chemical curing reactions are completed.
The Brilliant unit is capable of producing up to 30 tonnes of adhesive in a single shift
Estimating risks associated with extended curing
Nadgoundi explained the detail methodology for estimating extended curing risks with adhesives. “The estimation of significant risks is done by preparation of laminates by adhesives and testing them in the laboratory. We use our in house pilot laminator to fabricate a standard laminate structure. It is a representative structure formed with 12 microns polyester and 50 micron LDPE. A flexible pouch of 200cm2 area is formed using this laminate.
To simulate migration 3% acetic acid is filled in the pouches in 100ml quantities. The pouch is kept at 70 degree celsius for two hours to thermally accelerate the reaction of unreacted monomers with the contents of the pouch. Then reagents are used to identify the formation of aromatic amines by colouring them.
The samples are then evaluated under UV spectroscopy and GC. The exercise is continued at an interval of 24 hours till there is a saturation and a safe level of chemical curing is reached. We can see that at successive interval of 24 hours when the extracts are taken the colour can be seen as fading which is a physical indication of the concentration of developed aromatic amines.
Then as part of GLP, there is an evaluation by third party lab. What we measure has to be symmetrical with another set of measurement. After performing all these tests, we arrive at a chemical curing recommendation which is provided in the TDS of the product. If the converter follows this recommended duration for curing, then adhesives are 100% safe to be used for food packaging.
He added, “Similar to curing duration test, there are assessments made in line with global standards for residual volatiles and isocyanates.
In conclusion, Nadgoundi said, “Such collective assessment at our level and from third parties forms our basis for the food safety documentation that we provide to customers.This is how at Brilliant Polymers, we complete our commitment and this is how we claim that the adhesive that we offer to industry is food safe.”