Information on levels and types of microbes present in plant-based ingredients is scarce. See NIZO’s latest publication to find out how NIZO contributes to filling this white space and what was found in over 80 different ingredients, including pea, faba bean, oat, almond and coconut.

microbial contaminants

Prevent food waste and ensure food safety

When producing foods and beverages, quality and microbial stability are key prerequisites to ensure consumer safety and prevent unnecessary food waste. To achieve this, we need to know how to best predict potential risks and how to control microorganisms during and after food processing. This requires data and knowledge about the amount and types of microorganisms that may be introduced through the ingredients, as well as their growth and resistance characteristics. Such data are still largely lacking for plant-based ingredients and alternative foods.

Microbes in plant-based ingredients: from general ecology to safety risks

In collaboration with scientific and industrial partners, NIZO has isolated and identified bacteria (mostly spore-formers) from 88 different plant-based ingredients. The results show that the microbial loads of such ingredients vary widely not only between but also within ingredient groups, and can reach up to 5.3 Log10 CFU/g. In particular, spore-forming species that survive heat treatments have been detected, many of which are notorious for spoiling foods (e.g. by affecting colour, taste, odour and consistency) if the microorganism can grow in the finished product. Importantly, even food safety can be at risk if the spore-former, such as Bacillus cereus, can produce toxins during or after processing. In addition to financial losses, product recalls can result in damage to a brand’s reputation. Control measures to prevent this start with knowing what species are present in the ingredients and what we know about their resistance and growth characteristics.

The consortium coordinated by NIZO is of great value for Tetra Pak to reach market agreement with the other consortium partners on microbial challenges with plant-based products. The NIZO publication provides novel understanding of the microflora in the raw materials and accentuates current challenges with methods for the analysis of different plant- based raw materials. For me personally as a microbiologist, it has provided confirmation of my assumptions on what are the key challenges with plant-based products compared to milk. To have solid, reliable data is so much better than just your own educated guess. Stated by Birgitta Svensson, Ph.D., Technology specialist microbiology at Tetra Pak Processing Systems AB.

Access publication HERE

In this open access paper, the authors describe which types and concentrations of spore-formers are commonly found in different plant-based ingredient sources, including pathogenic species. This, along with information on the inactivation and growth properties of the various microorganisms encountered, is a critical component needed for microbial risk assessment. Such evaluation supports the effective design of conditions and formulations for plant-based food processing.

Reliable risk assessment and safety by design

The consortium will continue to determine spore inactivation and growth kinetics to better predict and minimize the food safety risks associated with the presence of spore forming bacteria in plant-based ingredients.

This work was funded by the European Union’s Horizon 2020 Research and Innovation Program under the Marie Skłodowska-Curie grant agreement No. 721456 (PathSense) and No. 956126 (E-MUSE) and by the Topsector Agri & Food (grant No. LWV21011), and was supported by industrial partners Ripple Foods, The Coca-Cola Company, SPX FLOW, Tetra Pak, Bel, Arla Foods, Yili, HP Hood LLC, FrieslandCampina and Cosun.  

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