Developing an Organic Pathogen Reduction Process for Spices

Spices are important food commodities and are growing in consumption. A 2017 U.S. Department of Agriculture report showed more than 260% increase in spice consumption by U.S. consumers over an 18-year period.

Spices belong to a group of low-moisture foods that are often assumed to be low risk in terms of food safety; however, these foods can be contaminated with harmful pathogens such as Salmonella. Within the 40-month period between January 2007 and April 2010, FDA reported 457 laboratory-confirmed illnesses, 68 hospitalizations, and one death in the United States caused by pathogen-contaminated spices. While the safety of spices is of the utmost concern to the spices industry, spice-associated recalls and outbreaks continue to make headlines.

Salmonella is the most common bacterial pathogen associated with spices. In a 2017 FDA study, investigators collected spice samples from retail establishments and from the import entry point to the U.S. to test for Salmonella prevalence. The study showed that the pathogen’s prevalence in shipments at import was significantly higher than in retail spices—6.6% and 0.25%, respectively.

These findings support the industry guidance by the American Spice Trade Association (ASTA) to apply a pathogen reduction treatment to products prior to their placement in retail stores. The study holds an even greater significance for the U.S., as most spices consumed here are imported. So, whether a spice is imported or grown domestically, it is crucial for the spice industry to continue to focus on food safety to protect consumers.

Once the Food Safety Modernization Act was signed into law, the spice industry changed course to focus on preventive-based controls to ensure food safety. Spice companies are required to conduct a hazard analysis, identify hazards that are reasonably likely to occur, and establish preventive controls for such hazards. The rules apply to both domestically produced and imported food. Many spice companies have demonstrated good corporate citizenship by implementing preventive food safety measures.

Now, more than ever, food safety is top of mind for today’s consumers. According to an international consumer study from the Mars Global Food Safety Center (GFSC), more than half of respondents identified food safety as a top-three global issue. Consumers also indicated that the issue has been exacerbated by the current global COVID-19 pandemic. Consumer demands for foods that are fresher, safer, and healthier continue to challenge spice manufacturers and processors to find more innovative food safety technologies.

Conventional Pathogen Reduction Technologies

Spices are primarily used for flavoring and coloring food. Therefore, it is essential to preserve the natural sensory and nutritional qualities of spices while achieving food safety. Currently, the most common pathogen reduction processes are:

• Irradiation;
• Fumigation with ethylene oxide (EtO); and
• Steam treatment.

Irradiation works by exposing food to radiant energy such as gamma rays and X-rays. EtO is a flammable, colorless gas that is widely used for sterilization, mainly for medical equipment. Steam treatment exposes food to very high temperatures for a predetermined time period.

A study published in the Journal of Food Science in 2017 assessed these three methods to determine if spice quality was affected (2017;82:1208–1215). After an analytical assessment, the results showed that all three processing technologies negatively impacted the quality and sensory integrity of spices. Irradiation affected the color of onion powder and resulted in the nearly complete loss of measured volatile compounds. EtO processing altered the visual and odor qualities of cumin seeds. Steam processing of black peppercorn resulted in a change in odor, supported by altered levels of volatiles. Steam processing also created visual differences for cumin seed.

In addition to changes in food quality, there are other factors to consider when using conventional technologies. The global pandemic has triggered a sharp increase in demand for irradiation and EtO supply for pharmaceutical and medical purposes, which has caused an interruption in the supply chain for spices, with a significant delay in microbial reduction treatment. This trend is expected to continue as the world navigates through the pandemic.