Pathogenic bacteria

Pathogenic bacteria are bacteria capable of causing disease in humans, animals, or plants, distinguished from the harmless or beneficial majority by virulence factors such as toxins, adhesins, and invasion systems. In foods the notorious members include Salmonella, Campylobacter, Listeria monocytogenes, and pathogenic strains of Escherichia coli, which cause illness through intestinal infection, invasion beyond the gut, or toxin production. Controlling them depends on hygienic handling, adequate cooking, validated kill steps such as pasteurization, and prevention of cross-contamination. Detection by culture, immunoassay, and PCR forms the backbone of food safety testing, with sampling plans and regulatory limits defining acceptable levels in different product categories.