Microbiological risks of plant-based products
The market for plant-based meat and dairy substitutes has grown significantly in recent years, thanks to increasing consumer demand. First seed milks appeared on the shelves, followed by plant-based alternatives to cheese. These new products differ in terms of composition and production, and can therefore pose a variety of risks when consumed.

The trend has encouraged pioneering food producers to develop innovative vegan food products for niche markets, thus stimulating a sustainable transition in the food sector.

These products may contain ingredients such as soy, coconut milk and various seeds such as almonds, cashew nuts and walnuts.

Different seeds and nuts are used as raw materials in the production of seed cheese. The basic steps are usually as follows:

  1. Preparation of seeds or nuts: The selected seeds or nuts must first be cleaned and properly prepared for processing.
  2. Soaking or processing: Seeds or nuts are sometimes soaked to make them softer and easier to use. They are then ground or processed using appropriate machinery or equipment.
  3. Preparation: Ground or processed seeds are added to other ingredients such as salt, spices, and sometimes yeast or probiotics for cheese fermentation.
  4. Fermentation: The mixture is fermented to develop the cheesy taste and texture. This process helps the cheeses to develop their distinctive flavour and texture.
  5. Moulding and drying: The fermented mixture is poured into a mould and allowed to dry. This helps the cheese to firm up and develop further.
  6. Maturing: The cheeses are then matured for a certain period of time to further enrich their flavour and achieve the desired texture.

These steps usually vary depending on the specific recipe and the method used by the manufacturer. Creativity and a combination of different vegetable ingredients in the production of seed cheeses allows the creation of a wide variety of tasty cheeses.

Although these products are generally considered by consumers to be healthy foods, it is important to highlight that they can also present food safety risks. Microbiological risks can arise from the contamination of seeds during harvesting, processing and storage with pathogenic bacteria that can persist for long periods of time in these low moisture foods.

In recent years there have been several cases of illnesses caused by vegetable cheeses made from seeds. The bacteria causing the outbreaks included Salmonella and Listeria monocytogenes .

Other pathogens have been identified in other plant-based products, for example, Cronobacter sakazakii was detected in vegan sausages, and Staphylococcus aureus and Bacillus cereus were sampled in another study. Among the recalled products, seed milks are also frequently found with potential microbiological contamination due to insufficient pasteurisation, including Cronobacter sakazakii and Clostridium botulinum.

Liebermann and colleagues (2023) investigated the fate of food-borne pathogens during the soaking and drying of nuts used in the production of plant-based products. The soaking of walnuts at 22 °C for 24 hours showed a significant increase in foodborne pathogen populations. The authors concluded that the conditions suggested in online recipes support the growth of pathogens.

Bartula and colleagues (2023) found that foodborne pathogens multiply faster in plant-based milk (almond, coconut and cashew) than in ultra-high temperature milk under certain conditions (8°C and 20°C).

Mukuna and colleagues (2021) tested 43 (31%) of 138 samples from almond, cashew and soy milk alternatives positive for Enterobacteriaceae. Antibiotic resistance to various drugs has also been shown.

In view of the above, the following questions arise:

  • What are the risks of these types of substitute products?
  • To what extent do pathogens occur in plant-based products?
  • What is the food safety culture of these new vegan food producing companies?
  • What knowledge do consumers have about the risks of these products?

To answer these questions, the food safety authority should extend its monitoring plan for plant-based fermented ready-to-eat products. In addition, food businesses producing such products should pay more attention to their food safety systems (HACCP) and consumers should be made aware of the potential risks.


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