Mixing raw food and kibbles, dangerous or not?

I've often been asked: “Is it ok to feed kibbles and raw meat at the same time?”. This is an eternal debate in the raw feeding community and many people end up being confused.

On one side, we have people saying that mixing raw food with kibbles will upset the stomach of your cats or dogs, while others say that it’s totally fine mixing kibbles and raw meat.

I myself didn’t initially know what to think about this, so I decided to do my own research and to share the results with you. I waited quite a while before writing this article because I first wanted to have some serious background in animal nutrition, which I now have! I've been enrolled in a feline and canine nutrition course at Southern Illinois University since the beginning of May.

The argument against mixing

You may have heard that you should never mix industrial pet food with raw food: because of this, when you switch your cat to a raw diet, people would argue that you should switch cold turkey from kibbles (or wet food) one day to raw meat the day after.
Similarly, you may have heard that adding fresh food to kibbles to improve the diet of your cat is not a good idea, as it will have the opposite effect.
The arguments most often used are that the pH at which the kibbles are digested in the stomach is higher (less acid) than the pH at which raw meat and bones are digested. Kibbles would induce a stomach pH of around 4, while the stomach pH after eating raw meat would be around 1-2. Therefore, mixing kibbles and raw meat will cause the stomach pH to be higher, resulting in detrimental effects. In fact, at a higher pH, not only the raw meat and bones won’t be digested correctly, but since an acidic pH has an important role in killing the bacteria present in raw food, there will also be a risk of bacterial contamination. 
Another argument against mixing the two types of food is that kibbles are much longer to digest than raw meat: if the meat stays too long in the digestive tract, it will induce bacteria growth.

A little reminder about the digestion process

Firstly, I will start with a simplified reminder of how the digestion process works.It starts with a mechanical action in the mouth: the cat chews its food. More precisely, as the jaw of the cat isn’t really adapted to chewing, cats tear the food into swallowable pieces. In the mouth, the food also mixes with saliva, which lubricates the food; however, saliva in cats has a minimal role in digestion as cats don’t secrete an enzyme to digest starch, contrary to us, humans.
The esophagus then transports in a few seconds the food in the stomach.
The stomach has several roles: it stores the ingested food, mixes it with gastric secretions to grind it, and forms a semifluid mass. The food is ground both by a mechanical action and by the acidity of the gastric secretions: they are composed of hydrochloric acid, which lowers the pH of the stomach to around 1-3. The gastric secretions also contain enzymes that allow starting to digest the proteins.
Finally, the stomach regulates the entry of the chyme, the semifluid mass of pre-digested food mixed with gastric secretion, into the small intestine. 
The chyme then arrives in the small intestine, which is the main site for proteins, lipids, and carbohydrates digestion and absorption. In the small intestine the pancreas releases bicarbonate salts that raise the pH of the chyme to around 6-7. This is because the enzymes which digest the nutrients need a neutral pH to function properly.
Finally, what remains undigested of the food goes in the colon. In the colon, water absorption and fermentation take place. 
What’s important to remember is that through the whole digestive tract, the food consumed by the animal varies in pH based on the stage of digestion. The pH in the stomach can also vary from one individual to another, and throughout the day.

The gastric pH

Now, let’s look at what science tells us about the gastric pH. At the best of my knowledge, at the time when this article was written (August 2020), there isn't any study explicitly comparing the gastric pH of a raw fed pet with the one of a pet fed an industrial diet.
However, there are several studies on the pH of dogs or cats fed with an industrial diet. The highlight from these studies is that the pH of dogs eating kibbles is in fact highly acidic, with an average pH of around 1-2, and there is a scientific consensus on these values [1], [2], [3], [4], [5], [6].
Similarly, cats fed an industrial diet have an average pH which is also highly acidic, at around 1-2 [7], [8], [9], [10].
Some older studies have shown a buffering effect that meals have: when the dog or cat ingests a big meal, the stomach gets quickly filled with food. As most food has a near-neutral pH (around 6), the gastric pH rises to around 6. Then, as the stomach releases acidic gastric secretion, the pH of the stomach goes back to an acidic level of 1-2. It seems that this process may have been used as an example to assert that kibble-fed pets have a higher stomach pH. However, in recent studies, the buffering effect of meals wasn’t observed at all: in the older studies, it may have been caused by the imprecision in the way of measuring the gastric pH.
Studies also show that in fact, as mentioned by the people against mixing raw and industrial food, the type of food which is eaten and its composition can influence the release of gastric secretion, and so influence the gastric pH. In particular, food with high protein content cause more gastric secretion [11]. However, even with these alterations, the pH still remains highly acidic.
This is some really good news, since highly acidic pH plays an important role (but not infallible) in protecting cats and dogs from the bacteria and pathogens in their food [12],[13],[14].

The stomach emptying

There aren’t many studies on the rate of stomach emptying when a cat or a dog eats raw meat. So, saying that cat or dog takes longer to digest kibbles doesn’t have any scientific basis. Additionally, there are many parameters that influence the speed of digestion, such as the size of the food particles, the fat content of the diet (high-fat diets slows the emptying), the moisture content of the diet, and even the shape of the dry food! [15],[16]
Moreover, The Raw Feeding Community did an experiment in which raw meaty bones took longer to digest than a kibble meal.
Taking into account all those parameters, the absence of proof and the anecdotal evidence shows that this argument isn’t very strong.
I would say that mixing raw meat and industrial pet food isn’t a problem, as it’s the role of the stomach to mix everything and let it pass into the small intestine when it’s “ready” to be digested. 

Another concern

The digestive tract, in particular the small intestine and the colon, is inhabited by bacteria that compose the gastrointestinal microbiota also called the gut flora of your pet. These bacteria have an important role in the digestion process: they synthesize vitamins and ferment fibers, but they also play a role in the overall health of your pets [17].
The profile of the gut flora depends on what your pets eat, and a study shows that the microbiomes of a dog eating kibbles and the one of a dog eating raw meat are different [18]. So, an abrupt change in food will disrupt the microbiota resulting in digestive issues such as diarrhea, constipation, and overall bad digestion. That’s why it’s always recommended to change between kibbles brand progressively or to introduce new food progressively.
This is what may happen when you switch cold turkey from an industrial diet to a raw diet.
Thankfully, this doesn’t always happen: in my personal case, I both switched Néline and Praline from one day to another and they didn’t have any digestive issues. However, they both already occasionally ate raw meat, so their gut flora was maybe already used to raw meat.

To conclude, in my opinion, there are no reasons not to add fresh food to an industrial diet. On the contrary, a progressive introduction seems to be the most gentle approach towards the gut microbiota. Moreover, as you may know, if you have a picky cat, a slow introduction is sometimes the only way to switch a cat to a raw diet. If you are in this situation, you shouldn’t be afraid to mix kibbles or wet food with raw meat.
Finally, if you currently don’t have the means to feed a raw diet for whatever reasons, you should know that there isn’t any risk to add some fresh food to an industrial diet. On the contrary, adding up to 10% of the daily caloric needs of your cat in fresh food can improve its diet.

Additional reads

The Raw Feeding Community made a great article on gastric pH

Additional details & Sources

You want some more details, you are nerdy and interested in the science behind this article. Here are some of the highlights and explanations from the studies I quote in this article.

[1] Mahar, Kelly M et al. “Gastric pH and gastric residence time in fasted and fed conscious beagle dogs using the Bravo pH system.” Journal of pharmaceutical sciences vol. 101,7 (2012): 2439-48. doi:10.1002/jps.23159

“Test meals (prepared on the day of each study) consisted of their standard meal (300 g) of dry dog food (Lab Diet #5007 made by PMI Nutrition International, St. Louis, Missouri) and wetted with 20–30 mL of tap water.

“The gastric pH under fasted conditions, regardless of whether the dogs were in their study or home cages, was characterized by relatively steady acidic pH punctuated by occasional pH spikes at irregular intervals.

“As noted by other investigators, the gastric pH in Beagle dogs reported in the literature using various methods is quite variable and controversial.

“Using the fixed BravoR capsule method under fasted conditions, it was observed that the pH was clearly acidic as well as during mealtime and for several hours postprandial. 

“While the fasted gastric pH in the dogs was similar to the monkey and human,  the dog lacks the steep and sustained elevation in postprandial pH, as seen in the human and monkey. One explanation may be due to a higher acid output in the dog, which prevents a buffering effect by the food consumed; thus, no increase in gastric pH. This is converse to the increase in gastric pH observed in humans, despite the peak acid output that occurs within 1 h post meal consumption. Another possibility may be the differing composition of the dog’s standard meal, thus, affecting the pH of the gastric contents.

“The premeal changes in gastric pH for the dogs in their home cage are probably linked to their anticipation of being fed due to the presence of the animal laboratory technician. While anticipating their meals, the dogs are likely undergoing a “Pavlovian” effect with hypersalivation, which can dilute gastric contents and therefore affect the hydrogen-ion concentration because of this dilution factor and the higher pH of saliva. To further expand on this hypothesis, the gallbladder may also be releasing its contents with the anticipation of a meal. 

“Therefore, outside (environmental) influences may also partially explain the literature observations of a more basic gastric pH in the dogs if they are in an anxious state and hypersalivation is occurring or the dogs are experiencing a “Pavlovian” food effect.

“The median-fed gastric pH values ranged between 1.7 and 2.0 for dogs in study cages and 1.5 and 1.7 for dogs remaining in their home cages among the three time periods analyzed. It is therefore apparent that the gastric pH remains acidic in the dog for several hours postmeal consumption with a trend for a higher gastric pH postmeal when the dog is in a study cage environment.

“In addition, this study provided further evidence that during and following a meal, the dog pH remains relatively acidic and there is no buffering effect of food to increase gastric pH in the present study conditions. There are conflicts within the literature regarding dog gastric pH and the different techniques used to collect the data and/or environmental factors may be contributing factors. As noted in these experiments, the housing of the dogs played a prominent role in their resultant pH profile.

=> My analysis: This recent study uses an accurate method to record gastric pH: it is very interesting and worth reading entirely if you are interested in the subject. The dogs were fed kibbles and their gastric pH was acidic during fasting, when fed and postmeal. In this study there was no buffering effect of meals. However, the environment of the dog played an important role in gastric pH during the anticipation of meals.

[2] Tolbert, K et al. “Efficacy of oral famotidine and 2 omeprazole formulations for the control of intragastric pH in dogs.” Journal of veterinary internal medicine vol. 25,1 (2011): 47-54. doi:10.1111/j.1939-1676.2010.0651.x

“Dogs were fed a commercial dog food. (Iams ProActive Health Minichunks, P & G Pet Care, Cincinnati, OH).

“The intragastric pH recordings of dogs in this study displayed wide fluctuations and lacked an obvious food buffering effect, which supports previous work. Wide pH fluctuations in placebo control dogs of the present study were mostly because of intermittent (0–2 daily) rapid rises of pH above 4 that presumably occurred because of duodenogastric reflux or the intake of chlorinated tap water. Interestingly, half of the pH peaks in our study occurred 10 or more hours postprandially, which helps to explain the high or variable basal gastric pH reported for dogs. Overall, however, the intragastric pH of our placebo control dogs was very low: it remained below 2 for more than 85% of the time, with a mean percent time intragastric pH ≥4 of only 4.7%.

=> My analysis: Recent study which reported highly acidic gastric pH in dogs fed commercial dog food.

[3] Sagawa, Kazuko et al. “Fed and fasted gastric pH and gastric residence time in conscious beagle dogs.” Journal of pharmaceutical sciences vol. 98,7 (2009): 2494-500. doi:10.1002/jps.21602

“The dry food was 5L18 High Density Canine Diet (PMI Feeds, St Louis, MO) which contains 36% fat, 27% protein and 37% carbohydrate (percent of ration)

“The mean gastric pH in the fasted dogs was 2.03. The gastric pH in fed dogs was 1.08 and 1.26 for 10 and 200 g fed, respectively. These values were significantly lower than that in fasted dogs (Fig. 4). This is unpredicted and counterintuitive as the gastric pH is reported to be higher in fed stomach in human due to the buffering effect of food. However, in dogs, it is reported that the initial buffering effect of food is not observed and there is no trend in pH over the first postprandial hour likely due to a higher peak acid output in fed dogs. 

“There was also a significant difference in gastric pH between 200 g fed dogs and 10 g fed dogs (Fig. 4). The gastric pH in dogs which received 10 g of food had significantly lower pH than that with 200 g of food. It is possible that the 10 g of food is not enough to buffer the gastric pH with high levels of acid secretion but 200 g of food had some more buffering capacity.

“The gastric pH in beagle dogs is controversial but generally believed to be higher, as some literature data suggested. Akimoto et al. measured the gastric fluids from a tube inserted intro the stomach through a catheter in fasted dogs and they found that the majority of animals had a basal pH of around 7. On the other hand, Mojaverian reported that the fasting gastric pH is comparable in dogs and human using the Heidelberg radio telemetry capsules (1.5  0.04 Dog vs. 1.1  0.15 Human). Our data showed that the gastric pH in fasted dogs was 2.03  0.59 which was one unit higher than human.

“The absence of the buffering effect of food in dogs has been reported. Youngberg et al. reported that when dogs were fed a meal of 70 g of steak and 30 g of chicken liver, the stomach pH using Heidelberg capsule ranged from 0.5 to 3.5 with a mean  SEM of 2.4  0.04 in 4 dogs

“It is reported that the pH in the anterior region in the stomach is higher than the posterior portion since the parietal cells tend to be localized in the lower part of the stomach

=> My analysis: This (quite recent) study found that the gastric pH of the tested dogs was highly acidic, both when fed and during fasting. This is in accordance with other recent studies that have shown there was no buffering effect after meals, as opposed to what happens in humans. The size of the meal also had an influence on the gastric pH. Finally, the method used to measure the pH could be the cause of the differences in literature in the fasted pH of dogs.

[4] Akimoto, M et al. “Gastric pH profiles of beagle dogs and their use as an alternative to human testing.” European journal of pharmaceutics and biopharmaceutics : official journal of Arbeitsgemeinschaft fur Pharmazeutische Verfahrenstechnik e.V vol. 49,2 (2000): 99-102. doi:10.1016/s0939-6411(99)00070-3

“The dogs were maintained on a standard solid meal of commercial diet (Pulina Co. Ltd., Japan)

“The pH of the gastric fluids in fasting dogs fluctuated, with a range of 2.7±8.3, but the majority of animals had a basal pH of around 7.

“The overall mean gastric pH was 6:8 ^ 0:2 (mean ^ SE), and was similar to the results reported in the literature [10,11]. On the other hand, a discrepancy was observed between the results obtained using an intubation method in this study and those obtained using a radio-telemetric device (Heidelberg capsule) [12].

“The reason for this discrepancy is unclear. However, possible explanation of it is that aspirates may have been obtained from the anterior region in the stomach. The anterior portion has a higher pH than the posterior portion of the stomach since the parietal cells tend to be localized in the lower part of the stomach [5]. One of the limitation of this study was that the location of the tip of the intubation tube in the stomach was not checked.

=> My analysis: This study is a bit old, but explains why in previous studies the fasted pH of dogs was reported as neutral around 7, while recent studies using radio-telemetric method (such as the Bravo capsule) report a highly acidic pH.

[5] Mojaverian, P.. “Evaluation of gastrointestinal pH and gastric residence time via the Heidelberg radiotelemetry capsule: Pharmaceutical application.” (1996).

“In the fasting state, gastric pH was comparable in dogs and humans (1.5 ± 0.04 vs. 1.1 ± 0.15, mean ± SEM), where postprandially a more acidic pH was reported in beagle dogs (2.1 ± 0.04 vs 3.6 ± 0.4). 

=> My analysis: It’s an older study. However, they used a radiometric method to record the pH and found an acidic pH both during fasting state, and after a meal.

[6] Lui CY, Amidon GL, Berardi RR, Fleisher D, Youngberg C, Dressman JB. Comparison of gastrointestinal pH in dogs and humans: implications on the use of the beagle dog as a model for oral absorption in humans [published correction appears in J Pharm Sci 1986 Dec;75(12):1207]. J Pharm Sci. 1986;75(3):271-274. doi:10.1002/jps.2600750313

“Gastrointestinal pH as a function of time was recorded for 4 beagle dogs and 10 human subjects using radiotelemetric pH measuring equipment. Results indicated that in the quiescent phase, gastric pH in the dogs (mean = 1.8 +/- 0.07 SEM) was significantly (p less than 0.05) higher than in humans (1.1 +/- 0.15). 

“The fasting intestinal pH in dogs was consistently higher than in humans, with an average canine intestinal pH of 7.3 +/- 0.09 versus 6.0 +/- 0.14 for humans. 

“The dogs were maintained on a Purina Laboratory canine diet 

=> My analysis: This study is old. It nevertheless shows that dogs fed an industrial diet had a highly acidic gastric pH around 2. Like other older studies, the fasting pH is reported to be neutral.

[7] Tolbert, M K et al. “Evaluation of Gastric pH and Serum Gastrin Concentrations in Cats with Chronic Kidney Disease.” Journal of veterinary internal medicine vol. 31,5 (2017): 1414-1419. doi:10.1111/jvim.14807

“Because the majority of cats with CKD were eating a prescription diet formulated specifically for cats with CKD (“therapeutic renal diet”; n = 7 of 10 cats with CKD), healthy cats also were fed a therapeutic renal diet during pH monitoring to minimize the effect of diet as a confounding variable. (Royal Canin Veterinary Diet Renal cat food (all controls and n = 5 cats with CKD); Hill's Prescription Diet K/D feline (n = 2 cats with CKD))

“pH parameters including mean ± SD gastric pH (CKD, 1.8 ± 0.5; healthy, 1.6 ± 0.3; P‐value = 0.23).

“Mean percentage time ± SD pH < 2 (median, range): 79.0 ± 12.7 %

=> My analysis: Recent study which compares the pH of cats with CKD and healthy cats. The pH of the healthy cats fed kibbles had a mean of 1.6 and 79% of the time a pH < 2. This study clearly shows that the pH of cats fed an industrial diet is highly acidic.

[8] Parkinson, S et al. “Evaluation of the effect of orally administered acid suppressants on intragastric pH in cats.” Journal of veterinary internal medicine vol. 29,1 (2015): 104-12. doi:10.1111/jvim.12493

“Cats were fed a maintenance diet (Hill's Science Diet Adult Light, Hill's Pet Nutrition, Inc, Topeka, KS)

“The mean percentage time ± SD the intragastric pH was ≥3 and ≥4 were 68.4 ± 35.0% and 57.8 ± 37.1% for fOT, 73.9 ± 23.2% and 55.7 ± 25.3% for ORP, 42.8 ± 18.6% and 22.4 ± 14.7% for famotidine, and 16.0 ± 14.2% and 9.6 ± 10.1% for placebo, respectively.

“In addition, a buffering effect of food on intragastric pH was not identified in the placebo control group (P  = .7851). The mean pH ± SD for cats in the placebo group over the 96‐hour period was 2.3 ± 0.4.

“In accordance with studies performed in dogs,12, 34, 35 this study did not identify a buffering effect of food on intragastric pH in cats receiving placebo. This may be a result of the pH capsule methodology, which unlike digital probes, allows direct adherence to the gastric mucosa and provides a direct measurement of intragastric pH. In addition, gastroduodenal reflux (defined as a rapid increase in pH > 4) occurred infrequently, with an average of 1.2 ± 1.2 episodes/day.

=> My analysis: This recent study shows two things. Firstly, healthy adult cats fed kibbles had a mean pH of 2.3 which is highly acidic, and only 9% of the time the pH was higher than 4.
The second observation (which is in accordance with 3 other studies), is that the buffering effect of food on the pH may have been caused by the way the pH was measured in the past. The buffering effect of food was nonexistent in this study.

[9] Šutalo, S et al. “The effect of orally administered ranitidine and once-daily or twice-daily orally administered omeprazole on intragastric pH in cats.” Journal of veterinary internal medicine vol. 29,3 (2015): 840-6. doi:10.1111/jvim.12580

“Cats were medicated daily at 6:30 am and 6:30 pm, 30 minutes before a standardized morning and evening meal (Hill's Science Diet Optimal Care Original Adult Cat Food.)

“Mean ± SD percentage of time intragastric pH was ≥3 and ≥4 was 67.0 ± 24.0% and 54.6 ± 26.4% for twice‐daily omeprazole administration, 24.4 ± 22.8% and 16.8 ± 19.3% for once‐daily omeprazole administration, 16.5 ± 9.0% and 9.6 ± 5.9% for ranitidine administration, and 9.4 ± 8.0 and 7.0 ± 6.6% for placebo administration 

=> My analysis: This study is recent and uses a modern way to monitor the cat’s gastric pH. The graph shows that most of the time the pH is between 0 and 2, for healthy cats eating kibbles.

[10] Brosey, B P et al. “Gastrointestinal volatile fatty acid concentrations and pH in cats.” American journal of veterinary research vol. 61,4 (2000): 359-61. doi:10.2460/ajvr.2000.61.359

“Cats were fed a free-choice balanced commercial laboratory dry diet.

“Mean pH was lowest in the stomach, which is consistent with the secretion of gastric acid, and highest in the ileum, which is consistent with the secretion of bicarbonate.

“Mean pH values were 2.5 (stomach)

=> My analysis: An older study on cats, reporting a mean pH of 2.5, for cats being fed free choice kibbles.

[11] F P Brooks, Effect of diet on gastric secretion, The American Journal of Clinical Nutrition, Volume 42, Issue 5, November 1985, Pages 1006–1019, doi.org/10.1093/ajcn/42.5.1006

“Meals stimulate gastric acid secretion in man and animals. 

“Protein meals are both effective buffers raising the gastric pH immediately after ingestion and potent stimulants to acid secretion lowering the pH as the meal is emptied. 

“These results show that protein-rich foods are the most potent stimulants to acid secretion. This correlates with their buffering capacity. 

=> My analysis: The study is old and experimental protocols are not well described, so I would take the result of the study with caution if no other studies show the same. It shows that meals high in proteins have a strong buffer effect, which means that they first raise the gastric pH, and then stimulate high acid secretion.

[12] Beasley, DeAnna E et al. “The Evolution of Stomach Acidity and Its Relevance to the Human Microbiome.” PloS one vol. 10,7 e0134116. 29 Jul. 2015, doi:10.1371/journal.pone.0134116

[13] Martinsen TC, Bergh K, Waldum HL. Gastric juice: a barrier against infectious diseases. Basic Clin Pharmacol Toxicol. 2005;96(2):94-102. doi:10.1111/j.1742-7843.2005.pto960202.x

“However, according to Howden & Hunt (1987), the main function of the gastric juice is to inactivate ingested microorganisms. Indeed, the concept of ‘‘gastric bactericidal barrier’’ was introduced many decades ago (Bartle & Harkins 1925; Garrod 1939).

“Subsequently, it has been repeatedly demonstrated that impaired gastric acid secretion predisposes to infection with a variety of infective agents (Drasar et al. 1969; Cook 1985 & 1994; Howden & Hunt 1987; Larner & Hamilton 1994). 

“The ‘‘gastric bactericidal barrier’’ is thought to reflect mainly the low pH, as other constituents of the gastric juice seem to contribute little to the barrier function (Giannella et al. 1972; Wilder-Smith et al. 1992). However, to separate the effects of HCl and pepsin seems hardly possible because the enzymatic activity depends on the gastric acidity

“Hπ ions have an inhibitory effect on gastrin cell activity at pH4, an increase in gastric pH leads to a decrease in gastrin cell inhibition and an increase in gastrin release (Walsh et al. 1975). At pH below 4 the gastric juice has a powerful bactericidal effect, killing exogenous bacteria introduced into the stomach usually within 15 min. The bactericidal effect is reduced at a pH above 4.0 (Gianella et al. 1972; Wilder-Smith et al. 1992). Anything that raises the intragastric pH above 4 will allow bacterial overgrowth (Gianella et al. 1972). It is of interest that in healthy subjects, gastric acidity is maintained at a pH4.0 (Cederberg et al. 1993; Waldum 1995).

“Upper gastrointestinal infections induce delayed gastric emptying and vomiting, thereby restricting further entry of pathogenic agents into the gastrointestinal tract. It seems likely that delayed gastric emptying enhances the bactericidal effect of the gastric juice.

Impaired gastric acid secretion has been shown to increase the susceptibility to several bacterial and parasitic agents.

[14] Smith, James L. “The role of gastric acid in preventing foodborne disease and how bacteria overcome acid conditions.” Journal of food protection vol. 66,7 (2003): 1292-303. doi:10.4315/0362-028x-66.7.1292

“The effect of an increase or decrease in gastric emptying time or of the temporary elevation of the gastric pH on the survival of bacteria in the stomach has received little attention. It is logical to assume that if the gastric emptying time is short, as it is for liquids, then pathogens have less contact with gastric acid and viable organisms may pass through the stomach into the intestine.

“The production of gastric acid by the stomach is an efficient mechanism for the destruction of pathogens ingested with food or water. However, a number of parameters can lead to hypochlorhydria or achlorhydria with a concurrent loss of the protective system afforded by gastric acid. 

[15] Goggin JM, Hoskinson JJ, Butine MD, and others: Scintigraphic assessment of gastric emptying of canned and dry diets in healthy cats, Am J Vet Res 59:388–392, 1998

[16] Armbrust LJ, Hoskinson JJ, Lora-Michiels NM, Milliken GA: Gastric emptying in cats using foods varying in fiber content and kibble shapes, Vet Radiol Ultrasound 44:339–343, 2003.

[17] Wernimont, Susan M et al. “The Effects of Nutrition on the Gastrointestinal Microbiome of Cats and Dogs: Impact on Health and Disease.” Frontiers in microbiology vol. 11 1266. 25 Jun. 2020, doi:10.3389/fmicb.2020.01266

[18] Sandri, M., Dal Monego, S., Conte, G. et al. Raw meat based diet influences faecal microbiome and end products of fermentation in healthy dogs. BMC Vet Res 13, 65 (2016). doi.org/10.1186/s12917-017-0981-z