Institutional kitchens, grocery stores, and food manufacturers are all businesses that generate a large volume of inedible food scraps as part of their operations. Conventionally, these have ended up in landfills where they release methane, a potent greenhouse gas. But a fast-growing number of kitchens and retailers are beginning to change this story by putting in place programs to collect and separate food scraps from their waste streams so they can be recycled sustainably. 

If you’re a food service or food retail manager at a site with a food scraps diversion program in place, you probably appreciate everything that it takes to keep it going smoothly. And, chances are, you know that bin contamination is one of the most common stumbling blocks such programs face. 

What is bin contamination? 

Food scraps bins become contaminated when inorganic material ends up in them. More often than not, these include: 

• Gloves
• Hairnets
• Plastic cups
• Straws
• Produce stickers 
• Non-compostable service-ware 

Why is bin contamination a problem? 

Contaminated food waste in bins can create a number of issues for the firms that transport and recycle it. Stray bits of plastic or metal, for example, slow the overall efficiency of recycling facilities because they have to be removed, while inorganic materials – especially glass or stretch wrap – can damage equipment. For these reasons, many haulers and recyclers will charge a fee for removing contaminants from a customer’s waste. 

Bin contamination is not only costly for businesses, but it also undermines a sustainable food system. When a recycler receives a load of food scraps that it decides is too contaminated, it may reject it altogether and send it to be landfilled or incinerated. Moreover, chemicals found on packaging, micro-plastics, and other inert materials that get into bins can find their way into the finished product (e.g., compost), affecting soil quality and even ending up in waterways and food supplies.

How to find the root causes of bin contamination 

If your business or facility kitchen is experiencing bin contamination, use the following three questions to perform a quick self-assessment to find a possible root cause. To answer a question, determine if the tell-tale signs listed underneath it reflect your own observations. If so, consider the correlating list of solutions we recommend as ways to course correct your program to get better results. 

1. Are staff involved? 

A lack of knowledge among staff is one thing, but a lack of buy-in is another. If staff don’t feel that efforts to divert wasted food from landfills matter, they may be less inspired to make sure non-organic materials stay out of bins. Very often this lack of interest comes down to organizational blindspots—how transparent is your program to staff and management? 

The Tell-Tale Signs

At the New York State Pollution Prevention Institute (NYSP2I), our work with food service providers and food retailers found that staff play a pivotal role in troubleshooting contamination. However, they are not always explicitly included in a program’s design. The following barriers are commonly cited as reasons that staff may not always participate: 

• Feedback vacuum: Staff are not regularly involved in discussions about program performance or efforts to improve it. 
• No sense of purpose: Accomplishments aren’t celebrated, such as the number of days passed without contamination or a tally of the total number of pounds of food waste that have been diverted from a landfill. 
• Old habits die hard: Separating out food waste may be completely new to most staff, so mistakes happen as they learn to break old habits and form new ones.

Recommendations  

Building a foundation of trust and ownership among staff and management around food waste diversion won’t happen overnight. However, we’ve found that making the following changes can help staff not only appreciate and understand the purpose behind a food scraps program, but to develop a sense of ownership in it:  

• Maintain a program board with goals and purpose that is visible to everyone.
• Incentivize staff to identify opportunities—have a public board where employees can post ideas.
• Celebrate small and large victories with staff on an ongoing basis.
• Reinforce the importance of the program routinely in conversation and staff huddles.
• Ask staff how they would improve the existing process.
• Provide timely constructive feedback and helpful nudges to encourage staff as they develop new habits. 

2. Are people confused? 

Confusion is one of the most common reasons a food scraps program can go awry. If staff or customers aren’t sure about basics like what goes into a food scraps bin or where bins are located, then contamination is only a matter of time.

The Tell-Tale Signs

Our work with industrial food service providers and food retailers found the following recurring themes on the issue of confusion:  

• It’s a well-kept secret: Most staff or customers—or both—aren’t aware that a food scraps collection program exists. 
• Differences aren’t obvious: It’s too difficult to distinguish bins designated for food scraps from those for other forms of waste, or compostable service-ware looks very similar to the non-compostable versions. 
• Mixed messages: Signage is limited, inconsistent, or non-existent. Likewise, if managers don’t fully understand how the system works, they’re unlikely to instruct staff correctly on using it.  

Recommendations 

First, determine who is getting confused. Kitchen staff? Management? Vendors? Or are customers the ones who don’t understand your existing system well? Then consider one or more of the following tactics to close the knowledge gaps: 

• Train customer-facing staff to mention the food scraps program when interacting with customers.
• Put cards, flyers, or stickers about the program in conspicuous locations.
• Add prominent signage near each bin location with information (and images) of how to source-separate.
• Add additional prompts or visual indicators, such as distinguishable bin lids, stickers, or more distinct receptacles for each waste stream.
• Update service-ware so that compostable and non-compostable versions are distinct from each other, or switch to only reusable or only compostable materials.

3. Are you making the same mistakes over and over again? 

A successful food scraps program requires a lot of planning and foresight. But even the best laid plans don’t always go as expected—and that’s OK. What matters is how you respond when things go wrong. By having a strategic process guiding your program, you will be better positioned to anticipate bumps in the road and, importantly, be ready to use those as opportunities to improve. 

The Tell-Tale Signs 

Don’t wait for contamination to happen—periodically take the pulse of your program by spot-checking bins, performing short audits, and other basic performance assessments. Below are some observations to take as red flags that process-level changes are needed.  

• Cognitive overload: There are too many sources of contamination. 
• No time to think: Staff are too busy to spend time separating out food waste. 
• Out of sight: Food scraps bins are located far from where staff are working. 
• Overflowing: The trash bins fill up too quickly, so staff use food scraps collection bins instead.
• Inseparable: Food waste and packaging are too difficult to completely separate.

Recommendations

Consider the process-level changes below, which can be implemented in response to red flags like those above.   

• Use magnetic screens inside bins to catch metal flatware.
• Add more bins to alleviate congestion at one location.
• Reduce sources of contamination (e.g., condiment cups, straws, or take-out cups).
• Regularly review and re-assess your approach to find inefficiencies or other opportunities to save staff time and help them work more effectively.
• Update procedures and onboarding material for new staff members to include food scraps separation process.
• Empty bins more frequently. 

Ready to troubleshoot more? 

A deeper look at the recommendations above—along with many more—can be found in Contamination in Food Scraps Bins: A Troubleshooting Guide for Food Retail and Food Service Managers, a practical tool we developed at NYSP2I. It includes a printable poster that staff can use to quickly track contamination when it happens.    

To create the tool, our specialists worked closely with food service providers and food retailers to better understand why bin contamination happens and what can be done to avoid it. They then took what we learned and translated it into simple troubleshoots for bin contamination, so businesses can build more resilient food scraps programs. 

We have a growing library of practical resources for preventing or diverting food waste. All of these are available to organizations, businesses, and communities anywhere in the world at no charge.

© 2023 Rochester Institute of Technology. Funding provided by the Environmental Protection Fund as administered by the New York State Department of Environmental Conservation. Any opinions, findings, and/or interpretations of data contained herein are the responsibility of Rochester Institute of Technology and its New York State Pollution Prevention Institute and do not necessarily represent the opinions, interpretations or policy of the State.