Health Canada’s Proposal to Enable the Use of Chitosan from White Button Mushrooms (Agaricus bisporus) as a Preservative in Various Foods

Notice of Proposal – Lists of Permitted Food Additives
Reference Number: NOP/ADP-0042
November 20, 2023

Summary

Food additives are regulated in Canada under Marketing Authorizations (MAs) issued by the Minister of Health and the Food and Drug Regulations (Regulations). Approved food additives and their permitted conditions of use are set out in the Lists of Permitted Food Additives that are incorporated by reference in the MAs and published on the Canada.ca website. A petitioner can request that Health Canada approve a new additive or a new condition of use for an already approved food additive by filing a food additive submission with the Department's Food Directorate. Health Canada uses this premarket approval process to determine whether the scientific data support the safety of food additives when used under specified conditions in foods sold in Canada.

Health Canada's Food Directorate received a food additive submission seeking approval for the use of chitosan from white button mushrooms (Agaricusbisporus) as a preservative in numerous foods at maximum levels of use ranging from 150 parts per million (ppm) to 1,500 ppm. The petitioner provided examples of products that would be included in the requested food categories. For example, by toppings, the petitioner refers to glaze, maple butter, marshmallow cream and fruit-based toppings. Chitosan is proposed for use in the requested foods to prevent the growth of microorganisms and subsequent spoilage.

The Food Directorate concluded that information related to the safety and efficacy of chitosan from white button mushrooms (A. bisporus) supports its use as an antibacterial agent and an antifungal agent in the foods of interest. Therefore, Health Canada proposes to enable this use of chitosan from white button mushrooms (A. bisporus) by adding the entries shown in the table below to Part 2 and Part 3 of the List of Permitted Preservatives.

Proposed Modifications to Part 2 and Part 3 of the List of Permitted Preservatives

The following information is proposed to be added in Part 2 and Part 3 of the List of Permitted Preservatives:

Item No.	Column 1 Additive	Column 2 Permitted in or Upon	Column 3 Maximum Level of Use and Other Conditions
C.3	Chitosan from Agaricus bisporus (average molecular weight 90 to 120 kDa and degree of deacetylation not less than 80%)	(1) Apricot nectar; Concentrated (naming the fruit) juice; Concentrates for unstandardized beverages containing fruit juice; Fruit-based or dairy-based smoothie beverages; Fruit-flavoured drinks; (naming the fruit) Juice; (naming the fruits) Juice; Peach nectar; Pear nectar; Unstandardized beverages containing fruit juice	(1) 600 p.p.m.
		(2) Bread; Unstandardized bakery products	(2) 1,000 p.p.m.
		(3) Caffeinated energy drinks; Unstandardized alcoholic beverages; Unstandardized fermented tea beverages; Unstandardized non-alcoholic water-based beverages; Unstandardized tea beverages; Unstandardized vegetable juices; Water-based beverages with vitamin and mineral nutrients added, except beverages with vitamins added in accordance with Part D of the Food and Drug Regulations	(3) 400 p.p.m.
		(4) Cheddar cheese; (naming the variety) Cheese; Cold-pack (naming the variety) cheese; Cold-pack cheese food; Cold-pack (naming the variety) cheese with (naming the added ingredients); Cold-pack cheese food with (naming the added ingredients); Cottage cheese; Cream cheese; Cream cheese with (naming the added ingredients); Cream cheese spread; Cream cheese spread with (naming the added ingredients); Processed cheese food; Processed cheese food with (naming the added ingredients); Processed cheese spread; Processed cheese spread with (naming the added ingredients); Processed (naming the variety) cheese; Processed (naming the variety) cheese with (naming the added ingredients); Unstandardized cheese-based sauces; Unstandardized processed cheese products; Unstandardized shredded cheese products	(4) 1,500 p.p.m.
		(5) Egg-based desserts; Fruit-based desserts	(5) 800 p.p.m.
		(6) Fillings; Toppings; Unstandardized table syrups	(6) 1,000 p.p.m.
		(7) Fresh pasta; Fresh noodles	(7) 200 p.p.m.
		(8) Frostings; Icings	(8) 400 p.p.m.
		(9) Liquid plant protein isolate-based products that resemble egg products	(9) 1,500 p.p.m.
		(10) Liquid soup bases; Liquid soup mixes; Soups	(10) 400 p.p.m.
		(11) Liquid table-top sweeteners	(11) 1,000 p.p.m.
		(12) Meal replacement bars; Nutritional supplement bars	(12) 200 p.p.m.
		(13) Plant-based products that resemble cheese	(13) 1,500 p.p.m.
		(14) Relishes	(14) 800 p.p.m.
		(15) Simulated meat products; Simulated poultry products	(15) 1,500 p.p.m.
		(16) Unstandardized coffee beverages	(16) 150 p.p.m.
		(17) Unstandardized confectionery coatings	(17) 1,000 p.p.m.
		(18) Unstandardized fruit spreads	(18) 1,000 p.p.m.
		(19) Unstandardized salad dressings	(19) 1,000 p.p.m.
		(20) Unstandardized sauces	(20) 1,000 p.p.m.
		(21) Unstandardized snack bars	(21) 200 p.p.m.
		(22) Unstandardized vegetable purées	(22) 400 p.p.m.
		(23) Yogurt	(23) 1,000 p.p.m.

Rationale

Health Canada's Food Directorate completed a premarket safety and efficacy assessment of the requested uses of chitosan from A. bisporus. The Department concluded that information related to allergenicity, chemistry, microbiology, molecular biology, nutrition, and toxicology supports the safety of chitosan from A. bisporus for its requested uses, and technical information supported it is effective as a preservative for the control of spoilage microorganisms in foods.

Chitosan is derived from chitin, a naturally occurring carbohydrate polymer that is widely distributed in nature (e.g., crustacean shells, fungal cell walls). The chitosan that was the subject of the premarket assessment is from chitin fibres found in the cell walls of non-genetically modified white button mushrooms (A. bisporus).

The production begins with the deacetylation of white button mushrooms. In this step, the mushroom biomass is combined with liquid sodium hydroxide and water in a vessel and heated. This thermal, alkali process removes acetyl groups from the chitin fiber found in the fungal cell walls and simultaneously hydrolyzes proteins and saponifies lipids from the biomass. The biomass is rinsed with water and exposed to an acetic acid solution in which the chitosan fibre is solubilized. The chitosan solution is separated from the mushroom biomass and then precipitated. The precipitated fibre is collected by centrifugation and rinsed with water, dried using a drum dryer, and milled into a fine powder.

The petitioner noted that the processing technology used to extract the fibre from white button mushrooms has the ability to produce chitosan within any molecular weight range. However, efficacy data demonstrate that chitosan with a molecular weight between 90 kDa and 120 kDa exhibits broad spectrum anti-bacterial and anti-fungal preservative effects in various representative food matrices (e.g., apple juice, yogurt, cheddar cheese, unstandardized alcoholic beverages, bakery products, plant-based products that resemble dairy products, plant-based products that resemble meats, condiments, jams, sauces, syrups, frosting, margarine, and mayonnaise) towards bacteria and fungi commonly associated with spoilage in these food matrices. As such, the petitioner chose this molecular weight range for their chitosan product. The petitioner further noted that their chitosan from white button mushrooms is naturally at least 80% deacetylated.

Chitosan is stable in acidic and high temperature conditions.

Following consumption, chitosan in the molecular weight range specified by the petitioner and with a minimum degree of deacetylation of 80% travels intact throughout the upper gastrointestinal tract with little to no degradation and absorption. Once in the colon, chitosan is fermented by the microbiota into dietary components, such as short chain fatty acids, hydrogen, carbon dioxide, and methane gas. Some of the potential microbial degradation products, such as N-acetylglucosamine and glucosamine, are already present in the diet. Other degradation products, such as chitosan oligomers, are unlikely to be absorbed in the lower intestine.

Studies with rats have found that high chitosan diets have the potential to cause reductions in the absorption from the gastrointestinal tract of the fat-soluble vitamins A and E, and the mineral nutrients calcium, magnesium, and iron. However, these findings have not been substantiated in humans from the available human clinical studies.

In Canada, white button mushrooms are not a priority food allergen. Food allergy to these mushrooms is rare, despite widespread consumption. The risk of allergic reaction from the requested uses of chitosan from A. bisporus is low.

The results of the premarket assessment support the safety and efficacy of chitosan from white button mushrooms (A. bisporus) for use as a preservative as set out in the table above. Health Canada is therefore proposing to enable the uses of this new food additive as shown in the above table.

Other Relevant Information

Chitosan from A. bisporus is not listed in the Codex General Standard for Food Additives (GSFA).^{Footnote 1} The CODEX General Standardfor Fruit Juices and Nectars provides for the use of chitosan as a processing aid at a maximum level of use in line with good manufacturing practices, although not for an antimicrobial function.^{Footnote 2}

The Australia New Zealand Food Standards Code does not contain any food additive permissions for the use of chitosan. However, chitosan sourced from Aspergillus niger is permitted as a processing aid in the manufacture of wine, beer, cider, spirits, and food-grade ethanol, at a maximum permitted level of Good Manufacturing Practice.^{Footnote 3}

Chitosan extract from fungi (Agaricusbisporus; Aspergillusniger) is permitted for use as a novel food in specified food category "Food Supplements as defined in Directive 2002/46/EC" at maximum levels "In line with normal use in food supplements of chitosan from crustaceans".^{Footnote 4} Chitosan of fungal origin is also an authorized oenological compound for specified uses.^{Footnote 5}

The United States Food and Drug Administration (FDA) had no questions at the time regarding the petitioner's conclusion that chitosan from white button mushrooms (Agaricusbisporus) is GRAS for use as an antimicrobial at levels ranging from 0.015 g to 0.15 g per 100 g of food (depending on the food) in a variety of foods similar to what has been requested in Canada, although the FDA noted "that an ingredient that is lawfully added to food products may be used in a standardized food only if it is permitted by the applicable standard of identity".^{Footnote 6}

Food additives such as chitosan from A. bisporus are required to meet food-grade specifications set out in Part B of the Regulations, where such specifications exist, or those set out in the most recent edition of the Food Chemicals Codex or the Combined Compendium of Food Additive Specifications where there are no specifications in Part B. The Food Chemicals Codex is a compendium of food-grade specifications for food ingredients, including food additives, published by the United States Pharmacopeial Convention. Specifications in the Combined Compendium of Food Additive Specifications are prepared by the Joint FAO/WHO Expert Committee on Food Additives (JECFA). The Combined Compendium of Food Additive Specifications is published by the Food and Agriculture Organization of the United Nations. There are no specifications for chitosan from A. bisporus in Part B, the Food Chemicals Codex or the Combined Compendium of Food Additive Specifications. However, the petitioner's specifications for chitosan from A. bisporus are consistent with those for chitosan from crustacean sources set out in the Food Chemicals Codex with respect to the mineral content (i.e., chromium, iron, and nickel) and concentrations of trace elements of most concern to human health (i.e., arsenic, cadmium, lead, and mercury).

Implementation and Enforcement

The proposed changes will be effective the day on which they are published in Part 2 and Part 3 of the List of Permitted Preservatives. This will be announced via a Notice of Modification that will be published on the Government of Canada's website.

The Canadian Food Inspection Agency is responsible for the enforcement of the Food and Drugs Act and its associated regulations with respect to foods.

Contact Information

For additional information or to submit comments related to this proposal, please contact:

Bureau of Chemical Safety, Food Directorate
251 Sir Frederick Banting Driveway
Tunney's Pasture, PL: 2202C
Ottawa, Ontario K1A 0K9
E-mail: hc.bcs-bipc.sc@canada.ca

If communicating by e-mail, please use the words "chitosan (NOP-0042)" in the subject line of your e-mail. Health Canada is able to consider information received by February 2, 2024, 75 days from the date of this posting.

References