What is HPP and is it really a good thing for your pet?

What is HPP and is it really a good thing for your pet?


By Carly Piatocha


In recent years, feeding a diet of raw meat, bones, organs and fresh vegetables has become quite main stream. Veteran raw feeders will no doubt remember a time in the not so distant past where feeding your animals in this manner meant your only option was making your pets meals at home. Raw food has now become the “old but new” way of feeding pets a wholesome and nutritious diet, and new raw food companies are springing up around the country. With this plethora of choice, it can be difficult for pet parents to know which company or companies to choose in order to ensure they are getting the best nutrition they can afford.

In order to set themselves apart from the crowd, reassure those nervous new-to-raw customers, and ensure the safety of their products, some companies have started offering raw food that is not only ready to thaw and feed, but also “bad bacteria free” through a process known as High Pressure Processing, or HPP for short.

HPP is a method of food processing that was discovered over a century ago when scientists realized that bacteria could not survive the high pressure environment of the ocean floor. HPP’s use in the commercial food industry however did not really begin until the 1990’s and has only become main stream in all areas of food production since 2000.

This process essentially uses high amounts of pressure, up to 90,000 pounds per square inch, in order to crush the outer membrane of prokaryotes (single celled organisms) and thereby kill harmful strains of bacteria such as Listeria, E-coli, and Salmonella. This level of pressure, put in a different way, is the equivalent of being six times deeper than the bottom of the Mariana’s trench – the deepest part of any ocean in the world! Essentially, packaged food enters one end of a completely enclosed chamber which is then filled with water and has equal amounts of pressure applied to all sides with processing times ranging from a few seconds to up to twenty minutes. According to several large and well known pet raw food companies, this process enables consumers to conveniently and safely feed raw food diets to their pets with no worry over bacterial contamination. Sounds too good to be true? In many ways, it is. Let’s explore the potential problems with feeding HPP raw pet food to your furry buddy.

There are several key issues with HPP processed food. First off, if bad bacteria are being crushed out of the food, what happens to the proteins of the meat itself as well as the good bacteria that are also present in raw meats? This is especially of concern given one of the main reasons many people choose to feed a raw food diet in the first place, despite its mess and expense, is for its unparalleled nutrition and absorbability. Although the raw food companies that use this method of processing often claim that foods are unaffected by it, the FDA themselves say otherwise. When raw, high protein foods go through this process, they will not only look visibly different, but the process also can also cause protein denaturation. Why is this a big deal? Well, picture a protein molecule as a curled up spring made of little amino acids. When a protein becomes denatured, usually through the application of heat or in this case high pressure, the string unravels and this renders the protein incapable of functioning.

There has also been a study done in 1999 proving that high pressure processing can alter the PH balance of foods by lowering it overall. This is actually part of the way more resilient strains of harmful bacteria are killed. Real raw meat is naturally highly acidic, and dogs are meant to have naturally acidic body systems. Overall, nutritionally speaking this is all bad news for your pet!

Even if we assume that the food produced under HPP is nutritionally equal to that of non-HPP raw food, we are still left with the inescapable fact that when a product is rendered completely sterile, it becomes an unbridled breeding ground for reinfection of the same dangerous pathogens that HPP killed off. It is a fact that few strains of bacteria can survive HPP, so even the neutral and helpful forms will be wiped out, meaning that if a product were to be re-infected with dangerous bacteria that cause illness, such as E-coli, there would be no competition for resources or space, allowing this invader to multiple at an unchecked rate. Of course, if eaten, this food would then pose a significantly greater risk for bacteria borne illness to both your pet and your family than if you had of just given Fido a piece of raw, high quality chicken as you cooked dinner. In fact, ironically, there is also evidence to suggest that the presence of high amounts of calcium in foods can offer protection to harmful bacteria when placed under pressure. Essentially, this means that any raw food that contains ground bone, can actually provide protection to E.coli bacteria making them much more resistant and able to survive a high pressure environment!

To bring home this point, it is important to note that one well known company, who will remain unnamed here, began using HPP processing in late 2009 and then proceeded to
voluntarily recall several batches of their raw frozen chicken patties on February 11th 2010 due to contamination by Salmonella bacteria. Yes, you read those dates correctly, this recall occurred AFTER the inception of HPP processing. This means of course, that even in sanitized factory conditions, it is a fallacy to believe that HPP processing can completely eradicate all harmful bacterium from your pet’s raw food meal.

The above case aside, admittedly most reinfection of HPP raw would occur in the conditions of the average home kitchen, not the manufactures. We do not live in a sterile world and bacteria are on and in everything, millions of them. I know its gross, but its true and it’s over all a good thing – we need them around to break up waste produced by larger creatures like us and hey, they were the first forms of life on our planet. In fact, in a study done on sixteen dogs intentionally fed Salmonella contaminated commercial raw food diets, none died or even became ill at all.

As long as common sense food safety protocols are followed such as defrosting and storing meat properly and thoroughly washing everything that has touched raw meat, there is little need for concern. Given the superior nutritional value of real raw and the fact that bacterial contamination is actually less likely given the reasons above – it is actually safer!

Even putting safety aside, the final issue with HPP is that it leaves companies who utilize the method with a difficult to solve conundrum. HPP is an expensive process. Therefore companies are faced with a choice; on one hand they can use high quality ingredients as well as HPP in order to ensure what they feel is a superior raw food product, however this product, while decent quality, will be very expensive for the average consumer to purchase due to the high cost of both ingredients and processing. On the other hand, some companies use HPP as an excuse to use subpar ingredients and an inappropriate amount of bone/muscle meat/organ ratios and assume that HPP will “clean” the food regardless so it will at least be “safe”. This results in a much more economical, and nutritionally poor and unbalanced, product.

Raw food companies that do not use HPP are forced to use overall higher quality ingredients to ensure nutritional balance and prevent illness. Most also employ a “test and hold” procedure where foods are kept frozen at the facility until such a time as they can be tested for low levels of bacteria and other food safety measures. Besides it is important to note that 36% of healthy dogs and 17% of healthy cats carry live Salmonella bacteria in their intestines and never become ill. As mentioned before, bacteria are a fact of life!

Overall, there are many choices out there nowadays in the world of raw pet food companies and every owner needs to make an educated choice for their pet while weighing the pro’s and con’s of the quality, safety and price of each option. If you are curious whether your pets food is made with HPP, a simple phone call to the company can help you uncover this information. The purpose of this article is to assist owners in making those difficult choices and to assure you that your hard earned pet food dollars are better put towards high quality, non-HPP raw diets, which are often cheaper as well as more nutritious and balanced.