How to Test for Lead in Spices:

A Guide to Detecting Heavy Metals

Reviewed and Approved by Steven Rogers, Chemistry Manager, Certified Laboratories 

1-Minute Summary 

  • Lead and other heavy metals like mercury, arsenic, and cadmium in spices don't have published limits by the FDA or the American Spice Trade Association, but there are efforts to minimize their presence. 
  • A strong food safety program with a robust hazard analysis and risk assessment is recommended for Quality Control professionals in the food industry.
  •  Spices can absorb heavy metals from the soil, thus warranting regular testing of finished products for lead and other heavy metals. 
  • Customer assurance regarding product safety can be achieved through consistent laboratory testing, verifying the absence of harmful heavy metals. 

Ensuring Food Safety: Testing for Lead and Heavy Metals in Spices 

The worldwide demand for spices and seasonings is growing, owing to increased demand for packaged foods and changing consumer lifestyles, particularly in the Asia Pacific region. However, many consumers want to be sure what they're eating is safe, especially when it comes to lead and other heavy metals – a long-time area of concern in the spice industry.  

That means quality control and quality assurance are vital to helping the spice industry realize its forecast growth. In this blog post, we will dive into the process of testing for lead and other heavy metals in spices.  

Periodic table of elements lead symbol on black pepper plant.  

Spice plants can absorb heavy metals like lead from the soil, making it an ongoing issue.  

How Do Lead and Other Heavy Metals Contaminate Spices? 

Heavy metal contamination in spices often originates in the growth phase of the spice plants. This contamination can occur through soil that has been polluted with heavy metals from various sources such as mining activities, industrial waste discharge, or the use of sewage sludge and contaminated water for irrigation.  

The uptake of heavy metals like lead, cadmium, and mercury by the plant's roots can lead to accumulation in the edible parts of the spice plants. Soil type, pH level, and the specific plant's ability to uptake heavy metals all contribute to the degree of contamination.  

Once the spice is harvested, further possibilities for contamination may occur during processing and transport. This can include the use of machinery with heavy metal components or storage in containers with lead-based materials. 

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How to Test for Lead and Other Heavy Metals in Spices 

Given the nature of the growth phase of spices and other potential points of contamination, testing for heavy metals is vital to safeguard your customers and protect your brand. Lead has always been a point of concern, but it's important to test for mercury, arsenic, and cadmium, too, as they are known to cause serious health problems in humans.  

Your first step is to send a representative sample from different parts of the batch to a reputable chemistry testing laboratory that is skilled in heavy metals testing. From there, the lab technicians will take over. 

 Inductively coupled plasma mass spectroscopy instrument testing for heavy metals like lead in spices.  

Once the sample is prepared, an Inductively Coupled Plasma Mass Spectroscopy Instrument is used to detect and quantify lead and other heavy metals.  

How Does a Laboratory Test for Lead in Spices? 

We take a deep dive into how to test for heavy metals in foods and other consumer products in this blog post. But, to summarize… 

  • The lab will homogenize the sample to ensure potential contaminants are evenly distributed. 
  • Acid digestion is the most common procedure used to extract heavy metals from the spice sample. 
  • The sample is first treated with acid to break down organic material and then heated in an oven to evaporate the solvent until all that remains is the inorganic residue. 
  • This is then dissolved in water and analyzed for heavy metals.
  • Certified Laboratories uses Inductively Coupled Plasma Mass Spectroscopy (ICP-MS) to detect and quantify the heavy metals present in the sample. 
  • Typically, spices are analyzed for lead, but you can include other metals for your samples. 

How Much Lead is Allowable in Spices? 

Here is where the topic grows hazy and often frustrating for manufacturers.  

While it's common knowledge that lead and other heavy metals cause health problems, the U.S. FDA does not establish specific limits on heavy metals in spices or other foods. However, FDA has announced "Action Levels" for lead in certain baby foods 

Instead, the Agency has historically issued cautionary statements to Americans that provide guidelines for eating certain foods susceptible to lead or heavy metal contamination, like seafood and rice-based baby food.  

So, at the Federal level in the United States, there is no clear answer. 

What About California Prop 65 Limits for Lead and Other Heavy Metals? 

Prop 65 provides a little more clarity on the issue. While it does not establish specific "limits" for these substances, it does set "safe harbor" levels. These levels consist of No Significant Risk Levels (NSRLs) for carcinogens and Maximum Allowable Dose Levels (MADLs) for reproductive toxicants. The safe harbor levels for the mentioned metals are shown in the table below.  

Table: Prop 65 Heavy Metals Levels for Spices



No Significant Risk Level (NSRL) 

Maximum Allowable Dose Level (MADL) 


15 micrograms per day 

0.5 micrograms per day 



0.3 micrograms per day (for inorganic mercury compounds) 


10 micrograms per day (for inorganic arsenic compounds) 



4.1 micrograms per day 



What Does the ASTA Say About Lead in Spices? 

The American Spice Trade Association, like FDA, doesn't publish limits for lead or other heavy metals in spices. However, the association is committed to minimizing heavy metals in spices and works with regulatory bodies to establish heavy metal limits for spices that are "protective and achievable". 

Where Does that Leave a QC Professional When it Comes to Safety? 

  • Start by developing a strong food safety program that includes a robust hazard analysis and risk assessment for your ingredients and manufacturing process. This is where a good food safety management system and properly implemented HACCP plan serve you well. It should go without saying, but follow Good Manufacturing Practices (GMPs), too.  
  • If there is sufficient risk – and given the nature of spices and their propensity to absorb heavy metals from the soil, there likely is – test your finished products for lead and possibly other heavy metals.  
  • Your customers want to know that the products that bear your label are safe, and laboratory testing is a great way to verify your product safety.  

When it comes to testing for lead in spices, Certified Laboratories has the chemistry testing expertise to provide you with accurate, comprehensive results with competitive turnaround time, so reach out for a quote. 

Topics: spices