Who Ya Gonna Call...

"I tried to think of the most harmless thing...something I loved from my childhood. Something that could never, ever destroy us." - Dr. Raymond Stantz, Ghostbusters

Over the last 25 years, since 1999, there have been 117 pet food recalls due to Salmonella. This accounts for 44% of all pet food recalls (266) in that same time period with the balance being made up of listeria, E. coli, foreign objects and formulation errors (e.g. Hill's Vitamin D and Blue Buffalo "feathers"). Of those 117 Salmonella recalls, 11 of them made the jump to humans and of those, 5 involved multi-drug resistant strains. Before you grab your officially licensed "raw" torches and pitchforks, this is a pet food industry concern; I'm not "targeting" any single format, just shining a light. Instead of getting lost in the weeds and arguing about which format has recalled the most pounds, I want to review the "kill steps" and safety protocols that are available and what consumers (and manufacturers) should expect from their pet food.

How Does Contamination Occur? - Bacterial pathogens find their way in to the supply chain through direct or indirect means. The salmonella pathogen is shed in fecal discharge (how's your coffee this morning?). This can end up in water systems, in vegetation and in slaughtered animals. Consumption of either can then infect the host (direct transmission) and continue the cycle. Close contact with infected "domesticated" animals (indirect transmission) is also possible. Focusing on the "ingredients" used in making of pet food, we need to ask the question, "what safety protocols are in place to prevent an outbreak?"

Hazard Analysis and Critical Control Points (HACCP) - This is a standardized, systemic approach in food safety that identifies, evaluates and controls potential hazards in the food production process. Its biggest "strength" is that it emphasizes prevention rather than simply relying on end-product testing. As part of the 2010 Food Safety and Modernization Act (FSMA), pet food is required by the USDA and FDA to follow HACCP procedures. While many companies are certified by a third party audit, other companies are self-audited. Unfortunately, some companies are just not compliant or do not follow the full 7 step principles of HACCP. Along with regulatory compliance, the purpose of HACCP is to enhance food safety, improve product quality and increase consumer confidence by demonstrating the company's commitment to food safety.

"Kill" Steps - Let's start this section with a clarification: a "kill" step is a reduction in the microbial load of harmful pathogens. It is NOT the complete elimination of pathogens. This is an important distinction because it helps explain how some food can be below the "safe" pathogen threshold when it leaves a facility but further down the road can have an excessive pathogen load.

Understanding "Log Reduction" - I apologize in advance for "math-ing" on you! A "log (logarithm) reduction" measures how much a decontamination process (aka "kill" step") reduces the concentration of a contaminant. Each increase in log reduction represents a 10-fold reduction in concentration. Using the image below as a guide, if the load in a sample contains 1,000,000 pathogens, a 1-log reduction "clears" 90% of the pathogens and leaves 100,000 remaining in the sample. CHEAT CODE - The number before log reduction is the number of decimal places that have been "cleared". A 3-log reduction is therefore a 99.9% (or 0.999) clearance which, in our example, would leave 1,000 pathogens. While the pet industry aims/strives for a 5-log reduction, there is no federal law or mandate in pet food. It is also important to note that when claiming a log reduction, it should be applied against the reduction of the most "robust" pathogen.

To accurately determine the log reduction achieved by a "kill" step in pet food production, a carefully designed testing process is necessary. Here's a simplified explanation:

Target Pathogen: The testing should focus on relevant pathogens that are a concern in pet food, such as Salmonella spp. or E. coli. In some cases, a non-pathogenic surrogate microorganism may be used. These surrogates should have similar heat resistance or other relevant characteristics to the target pathogen.

Preparing the Inoculum A known quantity of the chosen microorganism is grown in a laboratory to create a concentrated "inoculum." This inoculum will be used to contaminate the pet food samples. This concentration is carefully measured and recorded.

Applying the Kill Step The inoculated pet food samples are then subjected to the kill step being tested. It's crucial to precisely control and monitor the parameters of the kill step, such as temperature, time, and pressure. After the kill step, the treated pet food samples are analyzed to determine the number of surviving microorganisms. This is typically done using microbiological plating techniques.

Counting the pathogens: The number of colonies on each plate is counted. This number, along with the dilution factor, is used to calculate the number of colony-forming units per gram (CFU/g) of pet food. Once the initial and final concentrations of microorganisms are known, the log reduction can be calculated using the formula:

Log Reduction = log10 (Initial Number of Bacteria / Final Number of Bacteria)

Example:

??????????? Initial concentration: 1,000,000 CFU/g

??????????? Final concentration: 100 CFU/g

Log Reduction = log10 (1,000,000 / 100) = log10 (10,000) = 4

This indicates a 4-log reduction, meaning a 99.99% reduction in the number of microorganisms.

To ensure the reliability of the results, the testing should be performed with multiple replicates including samples where no "kill" step is applied. The entire testing process should be carefully documented and validated to ensure its accuracy and reliability. This may involve using standardized methods and participating in proficiency testing programs.

Different product formats can use different kill steps and some use multiple kill steps through their processing. Here are just some of the methods used:

KIBBLE: Extrusion: This is the most common process for producing dry kibble. The high temperatures and pressure involved in extrusion effectively reduce pathogens. Baking: Some companies use baking as an additional kill step or as the primary cooking method for certain types of kibble.

CANNED: Retorting: This is the standard method for sterilizing canned pet food. The cans are subjected to high temperatures and pressure in a retort, which eliminates virtually all microorganisms.

RAW: High-Pressure Processing (HPP): Many raw pet food companies use HPP to inactivate pathogens without cooking the food. Not very effective against spores. Bacteriophages: Some companies are exploring the use of bacteriophages as a natural way to control bacteria in raw pet food. Freezing is NOT a kill step. While it can significantly reduce the activity, the pathogens are only dormant.

FREEZE-DRIED: In-Line Heat/Steam: This is often used in combination with freeze-drying to provide a more robust kill step. Freeze-Drying: Itself significantly reduces moisture, which inhibits bacterial growth. ?

Food safety is of the utmost importance, not only for the health and well being of our pets but lapses in execution carry a risk for us as care givers as well. While you cannot completely eliminate the risk of harmful bacteria (cellular agriculture is a different topic), the efforts a company puts towards mitigating the risk is very telling. How they handle an issue and a recall is also an indication of the company's priorities but that is definitely another topic. Pet food manufacturers should know (AND SHARE) their results. There is no need to disclose proprietary processes but the analytics are important. This goes for nutritional information as well (essential amino acids, nutrients, digestibility, kcal distribution by macronutrient)! I've said it before and it is worth saying again: If your pet food company doesn't do these tests, why not? If they do, but they don't share their results, why not? Your pet is family! Don't let companies get rich on your love and devotion without full disclosure and transparency.