NETHERLANDS – A recent study conducted by scientists from NZIO Food Research and Wageningen University and Research (WUR) has unveiled concerning findings regarding microbial contaminants in plant-based ingredients used for dairy alternatives.

The research, which analyzed 88 different plant-based ingredients, revealed highly variable levels of contaminants and a significant presence of spore-forming microbes, particularly Bacillus and Clostridium strains.

The study aimed to enhance understanding about microorganisms present in plant-based ingredients, crucial for informed microbial risk assessments and strategies to mitigate hazards and spoilage risks during the production of plant-based foods.

Spore-forming bacteria, notably Bacillus and Clostridium, were the focus due to their resilience and prevalence in foods of plant origin.

The research highlighted the challenges faced by food manufacturers in controlling contamination by spore-forming microbes.

Despite employing various inactivation and preservation strategies, such as heat treatment or fermentation, the unique nature of plant-based dairy alternatives complicates the removal of spores.

Moreover, even raw plant materials used in these alternatives contain a diverse range of microorganisms, making contamination control a complex task.

Study methodology and findings

Samples of plant-based ingredients, including pulses (e.g., peas, faba beans, chickpeas, mung beans), cereals/pseudocereals (e.g., oats, rice, amaranth, quinoa), and drupes (e.g., coconut, almonds, cashews), were collected from multiple suppliers across different geographical locations.

The samples underwent analysis for various microbial counts, including total viable count (TVC), total aerobic mesophilic spore count (TMS), heat-resistant aerobic thermophilic spore count (HRTS), anaerobic sulfite-reducing Clostridium spore count (SRCS), and Bacillus cereus spore count (BCES).

The study revealed highly variable microbial loads among different ingredients, indicating the influence of uncontrollable factors throughout the production chain.

Particularly concerning was the presence of a significant proportion of spore-forming microbes, notably Bacillus and Clostridium strains, in the samples, posing challenges for removal during processing.

The diversity of contaminants was staggering, with the study identifying 33 different genera of bacteria across the samples.

Moreover, genetic analysis of Bacillus cereus group strains uncovered the presence of toxin genes, signifying the potential for foodborne infections or intoxication.

These findings underscore the complexity and importance of addressing microbial risks in plant-based foods, highlighting the need for stringent quality control measures to ensure consumer safety.

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