Checking for Fungi and Toxins in Common Culinary Herbs and Spices

Jim Crocker
14th June, 2024

Checking for Fungi and Toxins in Common Culinary Herbs and Spices

Image Source: Natural Science News, 2024

Key Findings

  • The study in Nairobi County, Kenya, found high levels of fungal contamination in spices and herbs sold in open-air markets and supermarkets
  • Aspergillus and Penicillium species, known for producing harmful mycotoxins, were frequently found in the samples
  • Many samples had ochratoxin A (OTA) levels above safe limits, posing significant health risks like liver and kidney damage
The recent study conducted by the Technical University of Kenya aimed to screen fungal diversity and ochratoxin A (OTA) levels in culinary spice and herb samples sold in open-air markets and supermarkets in Nairobi County, Kenya[1]. This study is crucial because OTA is a toxic secondary metabolite produced by certain fungi, and its presence in food can pose significant health risks. The research revealed a high frequency of Aspergillus and Penicillium species contaminating the samples. These fungi are known producers of mycotoxins, which are harmful substances that can contaminate food products. The isolated species included Aspergillus ochraceous, Aspergillus nomiae, Aspergillus niger, Aspergillus flavus, Aspergillus ustus, Aspergillus terrus, Aspergillus nidulans, Aspergillus clavutus, Penicillium crustosum, Penicillium expansum, Penicillium brevicompactum, Penicillium glabrum, Penicillium thomii, Penicillium citrinum, Penicillium polonicum, and Cladosporium cladosporioides. The study found that the total fungal count on spice and herb samples collected from various sources varied between 6 and 7 CFU/mL. Among imported spices, garlic had the highest fungal diversity, while cardamom had the least. For spices from both open market and supermarket outlets, cloves had the highest fungal diversity, while white pepper had the least. For herbs sampled from the open markets, basil was the most contaminated, while sage was the least. In supermarket samples, parsley, sage, and mint had the highest fungal diversity, and bay had the least. These findings are significant because they indicate the contamination of spices and herbs with OTA at high concentrations. The calibration curve for OTA was saturated at 40 µg/kg, with samples of garlic, cinnamon, red chili, basil, thyme, mint, sage, and parsley having levels above this. Among the spices, imported ginger had the highest OTA levels (28.7 µg/kg), while turmeric from the open market had the least (2.14 µg/kg). For herb samples, parsley from the open market had the highest OTA levels at 29.4 µg/kg, while marjoram from the open market had the lowest at 6.35 µg/kg. This study builds on earlier research that highlights the risks associated with mycotoxin contamination in food products. For example, previous studies have shown that Capsicum products, such as peppers, are highly susceptible to mycotoxin contamination during production, storage, and distribution[2]. Another study conducted in Ankara, Turkey, found that spice samples such as black pepper, red pepper, cumin, and turmeric were contaminated with various mycotoxins, including OTA[3]. The presence of OTA in food products is concerning due to its toxic effects. OTA has been found to cause a range of toxic effects, including hepatotoxicity (liver damage) and nephrotoxicity (kidney damage)[4]. The neurotoxic effects of OTA have also been evaluated, showing that OTA can induce cell death in neuronal cells through oxidative stress and DNA damage[4]. These findings underscore the importance of monitoring and controlling mycotoxin levels in food products to protect public health. The results of the current study demonstrate the widespread contamination of culinary herbs and spices with OTA, often beyond acceptable limits. This highlights the need for informed and sustainable mitigation strategies aimed at reducing human exposure to OTA through dietary intake of spices and herbs in Kenya. Such strategies could include improved agricultural practices, better storage conditions, and regular monitoring of mycotoxin levels in food products. In conclusion, the study conducted by the Technical University of Kenya underscores the significant health risks posed by OTA contamination in culinary herbs and spices. By identifying the fungal species responsible for this contamination and quantifying the levels of OTA present, the research provides a foundation for developing effective strategies to mitigate these risks and ensure the safety of food products.



Main Study

1) Screening of mycoflora and ochratoxin A on common culinary herbs and spices in Kenya.

Published 13th June, 2024

Related Studies

2) Overview of Fungi and Mycotoxin Contamination in Capsicum Pepper and in Its Derivatives.

3) Analysis of Multi-Mycotoxins in Commonly Consumed Spices Using the LC-MS/MS Method for Assessing Food Safety Risks.

4) Cytotoxic Effects of Ochratoxin A in Neuro-2a Cells: Role of Oxidative Stress Evidenced by N-acetylcysteine.

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