关键词: 宠物食品；益生菌；菌种合规性；质量评估；胃液耐受性；货架期稳定性

Abstract: To systematically evaluate the quality status of commercially available pet food probiotic products， this study conducted analyses from multiple perspectives，including strain compliance，accuracy of stated viable counts，strain stability，and gastric fluid tolerance. The objective was to provide a scientific basis for the establishment of industry standards and the enhancement of product quality. Forty -four commercially available products were collected. Strain compliance was assessed against the“Catalogue of Microorganisms Permitted for Use in Feed”. Viable counts were determined using the plate count method. Strain identification was performed via MALDI-TOF MS. Storage survival and digestive survival rates were evaluated through accelerated stability testing and in vitro simulated gastric fluid testing. The findings revealed that some products utilized strains，such as Clostridium butyricum，not currently listed in the aforementioned catalogue. Over 75% of samples had significantly lower viable counts than the labeled values. Strain identification consistency was poor，with the actual detection frequency being only 50% of that indicated on the labels. Significant differences were observed among strains：Bacillus licheniformis demonstrated high storage stability and gastric fluid tolerance；Lactobacillus plantarum declined rapidly and exhibited extremely low gastric fluid tolerance（<0.3%）；Saccharomyces cerevisiae showed low storage stability，although some samples displayed relatively high gastric fluid tolerance. Quality issues prevalent in current commercial products include non- compliant strain usage，inflated viable count claims，and deficiencies in strain authenticity and stability. This multi- dimensional study reveals key quality defects in this sector，providing data to support the development of relevant industry standards，optimization of production processes，and informed consumer choices.

Key words: Pet food；probiotics；Compliance analysis；Strain Compliance；Gastric fluid tolerance；Shelf-life stability