Dr. Linda Jacobson, Toronto Humane Society (with grateful thanks to Kyrsten Jade Janke)
Recent national survey data1 showed that 21% of pet owners struggled to access non-veterinary care during the pandemic, and the greatest need was for pet food. Companies and individuals regularly offer us donations of short-dated products, or products that are past their Best Before Date (BBD). In the past, a lot of product was discarded, or could not be accepted, because of the BBD. So when we were asked to look into this by one of the Toronto Humane Society managers, we were really excited by what we found.
In a nutshell: food can be safely consumed for a considerable amount of time beyond the BBD. This has drastically expanded our ability to distribute pet food to our local community.
Best Before Date (BBD) (also called “Sell By” or “Use By” Date) is often erroneously thought to be a hard expiry date for food. This is not the case at all. The quality of food gradually diminishes after the BBD, but not overnight! There is no safety concern for food beyond the BBD, so long as the packaging is intact and appropriate.
Most of the information we found pertains to human food, and human food banks. Human food past its BBD can be donated to charitable organizations; therefore, it is reasonable to accept pet food past its BBD. Note that the BBD only applies to unopened foods; once food packaging is opened or damaged, the BBD is no longer reliable.
Wet Food
Wet food can be safely used for up to two years past BBD, so long as the can is not damaged in a way that exposes the food to the environment. These should be no severe damage to the can, such as dents near seams or that could introduce pin-holes, and no bulging indicating gas formation from bacterial activity. Uncanned moist or wet food should not be used past the BBD, mainly because there isn’t enough information available to know how long these foods remain safe.
Dry Food
Boxed or bagged pet food and dry treats can be used up to six months past BBD, so long as the packaging is not damaged in a way that exposes the food to the environment (see Table). If the packaging is damaged in this way, it should either be discarded or immediately re-packed in an airtight/waterproof container (for example, if damaged during transport).
More Information on Pet Food Safety Risk Assessment
Water activity
Water activity describes on a scale from 0.0-1.0 the amount of free water in a product. This is an important measure since it can be used to understand the amount of water available for microbial growth. Dry dog food and treats are typically between 0.4-0.45 Aw (1). This is considered low, as it is less than 0.6 Aw, and therefore pathogenic bacterial growth is unlikely and the food is considered non-hazardous (2). However, 0.4-0.45 Aw can still support the growth of yeasts and molds. These organisms can cause spoilage and have a negative impact on food quality. Soft pet foods (0.6-0.85Aw) and canned wet food (≥0.85) are considered hazardous, in their ability to support pathogenic bacteria growth.
Exposure to moisture can increase the water activity of a food and increase the risk of pathogenic bacteria growth. Therefore, it is pivotal to store pet food in low moisture environments. Scudamore et al. (1997) found 10% of dry pet food contained low levels of ochratoxins (1). Mycotoxins have been associated with pet food since it forms on cereal grains like corn and wheat. Development of these toxins can be avoided by keeping the water activity of the stored food at its original level consistently.
Pet Food Water Activity Table (1,2,3)
| Item | Water Activity |
|---|---|
| Canned pet food | ≥0.85 |
| Soft moist pet food | 0.83 – 0.88 |
| Imitation Bone Treat | 0.679 |
| Imitation Bacon Treat | 0.669 |
| Dry pet food | 0.40 – 0.50 |
| Dry Cat Chow, Purina | 0.236 |
Chemical stability
Rancidity
Avoiding rancidity for more than 12 months is a challenge in the pet food industry (4). Dry pet food is particularly vulnerable to this reaction because kibble is often sprayed with a fat coating to preserve freshness and improve nutritive value, and which is a key compound in the reaction (2). Antioxidants are used to prevent this lipid oxidation process (4). Rancidity will produce an unpleasant odour and flavour, will often be rejected by pets, and can produce toxic compounds.
Maillard reaction
The Maillard reaction is used during pet food production to generate the characteristic taste, flavour and odour of pet food (5). This happens when amino acids react to simple sugars and cause a deeper brown colour to form. However, when this reaction continues it can produce some undesirable affects. Besides a visual change it is also implicated in the formation of off-flavour and can decrease the palatability of food (1).
To view and download Toronto Humane Society’s full protocol, click here. You are welcome to utilize this material but should acknowledge Toronto Humane Society as the source.
References
1. Timmons, R.A. (2007). Water activity as a tool for predicting and controlling the stability of pet foods. Accessed from https://en.engormix.com/feed-machinery/articles/water-activity-controlling-stability-of-pet-foods-t33837.htm. Was 2
2. Carter, B. (n.d.). Application notes: Is water activity the most important pet food specification? Accessed from https://neutecgroup.com/resource-library/water-activity/white-papers/173-water-activity-in-pet-food.
3. Schmidt, S.J. & Fontana, A.J. (2007). Appendix E: Water activity values of select food ingredients and products. Blackwell Publishing. Accessed from https://onlinelibrary.wiley.com/doi/pdf/10.1002/ 9780470376454.app5.
4. Chanadang, S., Koppel, K., Aldrich, G. (2016). The impact of rendered protein meal oxidation level on shelf-life, sensory characteristics, and acceptability of extruded pet food. Animals, 6(8), 44. https://doi.org/10.3390/ani6080044.
5. Van Rooijen, C. et al., (2013). The Maillard reaction and pet food processing: effects on nutritive value and pet health. Nutrition Research Reviews, (26), 130-148. DOI: 10.1017/S0954422413000103.
More information:
Arluke, A. (2021). Coping with pet food insecurity in low-income communities. Anthrozoos, 34(3), 339-358. https://doi.org/10.1080/08927936.2021.1898215.
B.C. CDC. (2019). Providing nutritious and safe food: Guidelines for food distribution organizations with grocery or meal programs. Accessed from http://www.bccdc.ca /resource-gallery/Documents/Guidelines%20and%20Forms/Guidelines%20and%20Manuals /EH/FPS/Food/FDO%20Guidelines%20with%20Grocery%20or%20Meal%20Program.pdf.
FDA. (2019). Tips for safe handling of pet food and treats. Accessed from https://www.fda .gov/animal-veterinary/animal-health-literacy/tips-safe-handling-pet-food-and-treats.
Food Bank Canada. (2013). Guideline for distributing food past the best before date. Accessed from http://www.bccdc.ca/resource-gallery/Documents/Educational%20Materials /EH/FPS/Food/FoodBanksCanadaGuidelinesforFoodShelfLife2013.pdf.
USDA. (2019). Food Product Dating. Accessed from https://www.fsis.usda.gov/food-safety/safe-food-handling-and-preparation/food-safety-basics/food-product-dating.
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