Table 1. Prevalence of Salmonella contamination in different types of pet foods reported in various studies

Pet food category	Reported prevalence	Key findings and interpretation
Overall trend	Animal-derived ingredients in pet food: ~60% (w/w) vs. ~2% (w/w) in livestock feed [18].FDA survey: 82% positive in animal origin vs. 37% in plant origin [19].	High proportion of animal-derived raw materials is the major contamination source.
Dry food (kibble)	26.5% in early survey [20].Poland: 0.97% (22/2,271) [16].USA: 0.41% (1/240) [21].Defective batch: 44% (11/25) [22].Lebanon: 64% (42/66; culture only, no confirmation) [23].	Extrusion (high temp/pressure) reduces survival, but post-processing cross-contamination is critical. Salmonella can persist up to 19 months in kibble.
Semi-moist food	0% in 240 pouched samples and four commercial products [16,24].	Low prevalence; heat treatment and preservatives considered effective.
Wet food (canned)	Most studies: 0% (sterilized, hermetically sealed) [24].Non-sterile/open packed: 26% (26/99) [23,25].	Safe when sterilized and sealed; non-sterile products remain at risk.
Treats and chews	Canadian pig ears: 51% [26].U.S. treats: 41% [27].Specific distributor: 28.4% [28].Brazil: 0.93% (1/108) [29].UK: 16% (13/84) [30].Other: 0% (0/190) [16].	Dehydrated animal by-products often sold unpackaged without heat treatment → higher contamination risk.
Raw meat-based diets (RMBDs)	Range 0%–80% depending on study.Nemser et al.: 7.6% [16].Joffe & Schlesinger: 80% [31].Thailand: 53%; Japan: 12%; Chile: 26.2% [32].Europe (Sweden, Switzerland, Italy): 3%–7% [32].	Considered high-risk products due to lack of heat treatment. Identical serotypes found in pets’ feces, indicating possible zoonotic transmission. FDA advises against feeding raw diets. Mitigation: HPP, irradiation, bacteriophage preparations.

Values reported across studies differ by country, product type, and methodology. Some surveys relied on culture results only without confirmatory testing (e.g., Lebanon, wet food). Reported prevalence should therefore be interpreted with caution.
FDA, Food and Drug Administration.