Evaluating Potential Risks of Food Allergy and Toxicity of Soy Leghemoglobin Expressed in \u3ci\u3ePichia pastoris\u3c/i\u3e

Scope: The Soybean (Glycine max) leghemoglobin c2 (LegHb) gene was introduced into Pichia pastoris yeast for sustainable production of a heme-carrying protein, for organoleptic use in plant-based meat. The potential allergenicity and toxicity of LegHb and 17 Pichia host-proteins each representing ≥ 1% of total protein in production batches are evaluated by literature review, bioinformatics sequence comparisons to known allergens or toxins, and in vitro pepsin digestion. Methods and results: Literature searches found no evidence of allergenicity or toxicity for these proteins. There are no significant sequence matches of LegHb to known allergens or toxins. Eleven Pichia proteins have modest identity matches to minor environmental allergens and 13 Pichia proteins have significant matches to proteins from toxic sources. Yet the matched allergens and toxins have similar matches to proteins from the commonly consumed yeast Saccharomyces cerevisiae, without evidence of food allergy or toxicity. The demonstrated history of safe use indicates additional tests for allergenicity and toxicity are not needed. The LegHb and Pichia sp. proteins were rapidly digested by pepsin at pH 2. Conclusion: These results demonstrate that foods containing recombinant soy LegHb produced in Pichia sp. are unlikely to present an unacceptable risk of allergenicity or toxicity to consumers

Approaches to assessing safety of novel and genetically modified foods

Evaluation of novel and genetically modified (GM) foods for consumption is critical to regulatory review processes globally for potential risks of food allergy or toxicity as well as for marked changes in nutrients. So far the current evaluation process has proven to be adequate in identifying potential risk. However, assessing safety may be difficult in the future as complex genetically engineered products are continually produced. There are also very few methods available for fully evaluating whole foods. It is therefore necessary to consider improved methodologies and strategies to ensure that the present level of safety of GM-derived and novel foods are maintained. The goal of this study was to employ various techniques suggested in the risk assessment protocol to assess the safety of foods. Different heme (six) and Rubisco (four) proteins intended to be used in a GM food product were evaluated for potential risks of toxicity and allergenicity. Bioinformatics analyses comparing amino acid sequences of these proteins to known allergens and toxins on well curated databases such as AllergenOnline.org and the IUIS Allergen Nomenclature Database revealed that the proteins had low sequence identities to known allergens and toxins suggesting there is no evidence for their safety concern. Further by using, a murine model of sensitization and elicitation together with a basophil mediator release assay, we assessed whether the food matrix (lipids) as well as processing may have an effect on peanut allergenicity. No significant differences were observed when defatted and non-defatted raw or roasted peanut extracts were used to sensitize and elicit an allergic immune response in the mouse model. Also, the different processing methods, boiling, dry roasting and Ghana roasting compared to raw peanuts did not show a significant effect on peanut allergenicity in the mouse model. Thus, this study was not able to explain the differences in prevalence rates of peanut allergy in different parts of the world where different forms of processed peanuts are consumed. The mouse model and mediator release assays showed similar results suggesting that additional proteins and foods may need to be tested in the mouse model and compared to human studies

Evaluating Potential Risks of Food Allergy and Toxicity of Soy Leghemoglobin Expressed in \u3ci\u3ePichia pastoris\u3c/i\u3e

Scope: The Soybean (Glycine max) leghemoglobin c2 (LegHb) gene was introduced into Pichia pastoris yeast for sustainable production of a heme-carrying protein, for organoleptic use in plant-based meat. The potential allergenicity and toxicity of LegHb and 17 Pichia host-proteins each representing ≥ 1% of total protein in production batches are evaluated by literature review, bioinformatics sequence comparisons to known allergens or toxins, and in vitro pepsin digestion. Methods and results: Literature searches found no evidence of allergenicity or toxicity for these proteins. There are no significant sequence matches of LegHb to known allergens or toxins. Eleven Pichia proteins have modest identity matches to minor environmental allergens and 13 Pichia proteins have significant matches to proteins from toxic sources. Yet the matched allergens and toxins have similar matches to proteins from the commonly consumed yeast Saccharomyces cerevisiae, without evidence of food allergy or toxicity. The demonstrated history of safe use indicates additional tests for allergenicity and toxicity are not needed. The LegHb and Pichia sp. proteins were rapidly digested by pepsin at pH 2. Conclusion: These results demonstrate that foods containing recombinant soy LegHb produced in Pichia sp. are unlikely to present an unacceptable risk of allergenicity or toxicity to consumers