Systematic Review and Meta-Analysis of Quality Claims Associated with Fresh Pet Food: Evaluating Scientific Evidence for Additives, Ingredient Quality, and Effects of Processing in Pet Nutrition.

The fresh pet food market has experienced substantial growth, with manufacturers making quality claims that influence consumer purchasing decisions and veterinary recommendations. This systematic review evaluates the scientific evidence supporting three prevalent claims associated with fresh pet food: that additives, preservatives, and fillers are harmful to pet health; that human-grade ingredients provide superior safety and nutrition compared to feed-grade ingredients; and that whole ingredients offer health advantages over processed ingredients. A comprehensive literature search across the SCOPUS, PubMed, and EBSCO databases identified 4888 potential studies. Following systematic screening and quality assessment, 121 studies met inclusion criteria for analysis. Bayesian meta-analyses of additives (n = 60 studies) and preservatives (n = 39 studies) revealed pooled risk differences of 0.0006 and 0.0003, respectively, with Bayes factors strongly supporting null hypotheses of no adverse effects within regulatory limits. Random-effects meta-analyses of processing effects on ingredient digestibility (n = 102 comparisons, SMD = 1.971, p = 0.005) and nutrient content (n = 137 comparisons, SMD = 1.405, p < 0.001) demonstrated significant heterogeneity, with outcomes highly dependent on ingredient type and processing method rather than processing intensity. Human-grade versus feed-grade ingredient comparisons (n = 6 studies) showed methodological limitations and high risk of bias, preventing definitive conclusions. Current evidence does not substantiate claims that approved additives and preservatives cause harm when used within AAFCO guidelines. Processing effects vary substantially by ingredient matrix and method, with both beneficial and detrimental outcomes observed. This review identifies critical research gaps and provides recommendations for evidence-based marketing practices, targeted research priorities, and informed decision-making by industry professionals and consumers.