Introduction
Propylene glycol is a synthetic liquid substance that absorbs water. It is commonly used as a solvent and emulsifier in a variety of products, including food, personal care products, antifreeze, and pharmaceutical drugs. In the food industry, propylene glycol is used as a humectant to help retain moisture and extend shelf life. It is found in a wide range of foods, including salad dressings, cake mixes, soft drinks, seasoned salts, and pet treats. Propylene glycol is frequently added to dog treats to help keep them soft and chewy. Without propylene glycol, dog treats would become dry, crumbly, and less palatable.
What is Propylene Glycol?
Propylene glycol is a synthetic liquid substance that is derived from petroleum. It is produced by the hydration of propylene oxide, which is obtained by hydrocarbon oxidation. Propylene glycol has many industrial applications and is used as a solvent and preservative in a variety of products, including food, cosmetics, pharmaceuticals, and tobacco.
Chemically, propylene glycol is an organic compound belonging to the alcohol family. Its chemical formula is C3H8O2. At room temperature it is a clear, colorless, and hygroscopic liquid with a sweet taste resembling that of glycerol. Propylene glycol has the ability to absorb water, so it can help retain moisture in certain products.
Some key properties of propylene glycol that enable its use as a solvent and preservative:
- Soluble in water
- Hygroscopic (absorbs water)
- Low volatility
- Relatively non-toxic
Overall, propylene glycol is a petroleum byproduct valued for its solvent properties and ability to absorb moisture, which allows it to function as a preservative and stabilize foods.
Uses in Human Food
Propylene glycol acts as a moisture-carrying solvent and is commonly used in a variety of processed foods. According to Healthline, propylene glycol helps keep foods moist and can enhance flavor retention (1). It is found in cake mixes, salad dressings, margarine, whipped cream, coffee creamers, and more.
Propylene glycol in small quantities can improve the texture of baked goods to be more tender. It is also added to other foods like ice cream to prevent freezer burn. The FDA considers propylene glycol safe for human consumption and has approved its use in food products (2).
Overall, propylene glycol serves important functions related to texture and shelf life in many common foods. However, some people choose to avoid it due to concerns about potential health effects.
Sources:
(1) https://www.healthline.com/nutrition/propylene-glycol#uses
(2) https://foodinsight.org/what-is-propylene-glycol/
Uses in Pet Food
Propylene glycol is commonly used as a humectant in semi-moist dog treats and pet foods. This means it helps preserve moisture and texture to keep the kibbles soft and chewy (https://www.dvm360.com/view/propylene-glycol-educate-yourself-and-your-veterinary-clients). Propylene glycol prevents dryness by retaining water. Without it, the treats would become hard and crunchy quickly after opening.
In addition to maintaining texture, propylene glycol also carries flavors and enhances the taste of pet foods. The propylene glycol helps evenly distribute flavor throughout each piece of kibble to promote a consistent flavor profile in moist and semi-moist dog treats (https://iheartdogs.com/should-you-avoid-dog-foods-with-propylene-glycol/).
Is Propylene Glycol Safe?
Propylene glycol is generally recognized as safe by the FDA for use in food, cosmetics, and medicines (https://www.atsdr.cdc.gov/csem/ethylene-propylene-glycol/propylene_glycol.html). The FDA considers an average daily dietary intake of propylene glycol as generally safe for human consumption. In low doses, propylene glycol shows very low toxicity.
According to the CDC’s Public Health Statement on propylene glycol, it is considered a safe chemical and not routinely tested for, unless specific exposure occurs through use in cosmetics or medicines (https://wwwn.cdc.gov/TSP/PHS/PHS.aspx?phsid=1120&toxid=240).
Overall, in small, controlled doses, propylene glycol is not considered dangerous and the FDA deems it generally safe for use in consumables.
Benefits in Dog Treats
Propylene glycol offers some benefits when used in the manufacturing of dog treats. One of the main benefits is that it helps retain moisture in treats like jerky or chews. For example, petfoodindustry.com notes “In pet treats, propylene glycol will help retain moisture, maintain texture and prevent mold in semi-moist and soft-moist treats” (source). Propylene glycol prevents these types of treats from drying out and becoming too hard or brittle.
Another benefit is that propylene glycol is easy to work with during manufacturing. The additive can help simplify production and allow treats to be made in large batches more easily. As dvm360.com explains, “It helps create an even distribution of moisture throughout the food or treat” (source). This makes propylene glycol a useful tool for commercial pet food producers.
Potential Risks
While propylene glycol is considered safe in small doses, there are some potential risks to be aware of:
Large doses could cause kidney issues. According to Pet Poison Helpline, propylene glycol can potentially cause kidney damage at high doses[1]. The kidneys are responsible for filtering waste from the bloodstream, so ingesting large quantities of propylene glycol could overwork the kidneys.
Pets sensitive to it may experience allergies. Some pets may have sensitivities or allergies to propylene glycol[2]. Reactions could include mild gastrointestinal signs like vomiting or diarrhea to more severe signs like facial swelling. If a pet has a known allergy, it’s best to avoid treats containing propylene glycol.
[1] https://www.petpoisonhelpline.com/poison/propylene-glycol/
[2] https://www.dvm360.com/view/propylene-glycol-educate-yourself-and-your-veterinary-clients
Alternatives
There are some alternative humectants that can be used in place of propylene glycol in dog treats and foods. Some common alternatives include:
Glycerin – Glycerin is a pet-safe moisturizing agent made from plant oils or animal fats. It helps maintain moisture levels and texture in pet foods. Glycerin comes from natural sources and is generally considered safe for dogs.[1]
Sorbitol – Sorbitol is a sugar alcohol that is used as a humectant in some pet foods and treats. It helps retain moisture and has a sweet taste. Sorbitol occurs naturally in some fruits and vegetables. It provides moisture benefits similar to propylene glycol.[2]
Xylitol – Xylitol is a sugar alcohol that is extremely toxic to dogs. Even small amounts can cause hypoglycemia, liver damage, and potential death in dogs. Xylitol should never be used as an ingredient in dog foods or treats.[3]
When looking for alternatives to propylene glycol, glycerin and sorbitol are typically good options. But xylitol should always be avoided in any products meant for dog consumption.
[1] https://www.dvm360.com/view/propylene-glycol-educate-yourself-and-your-veterinary-clients
[2] https://kabo.co/blog/dog-food-without-propylene-glycol
[3] https://www.akc.org/expert-advice/nutrition/what-you-need-to-know-about-xylitol-poisoning-in-dogs/
Dosage Guidelines
The FDA allows up to 2.5% propylene glycol in soft moist pet foods. This is considered a safe amount for consumption by dogs according to the FDA’s Generally Recognized As Safe (GRAS) standards for food additives [1]. Higher levels may potentially cause toxic effects.
For treats and other pet foods, the FDA advises keeping propylene glycol content under 1% [2]. Levels up to 1.5% have been shown to be safe, but there is less data on the long-term effects of prolonged ingestion above 1%.
Pet owners should check the ingredient lists on treats and foods and aim to pick options that have limited amounts of propylene glycol, preferably under 1%. Monitoring intake levels from all sources is advised.
Conclusion
Propylene glycol is a common ingredient found in many dog treats and human foods. It serves important purposes like retaining moisture, enhancing flavor, and stabilizing fat. While approved as safe by the FDA up to certain dosage limits, owners should still be aware of potential risks like allergies. When buying treats, check the ingredients list and proportions. Consider alternative options without propylene glycol if your dog has sensitivities. The bottom line is moderation – treats should compose only a small portion of your dog’s diet.
The main takeaway for pet owners is to be an informed consumer. Recognize that propylene glycol has benefits but also potential drawbacks. Do your research on dog food ingredients and listen to your veterinarian’s advice. Every dog is different, so pay attention to how your dog reacts to certain treats. Focus on high quality nutrition from your dog’s regular meals, and use treats sparingly.