Microbial loads and antibiotic resistance patterns of Staphylococcus aureus in different types of raw poultry-based meat preparations

Abstract

The hygiene status of raw chicken-meat preparations from retail outlets in North-Western Spain was investigated. Microbial counts (aerobic plate counts (APCs), psychrotrophs, Enterobacteriaceae, fecal coliforms, enterococci, pseudomonads, fluorescent pseudomonads, yeasts and molds, and Staphylococcus aureus) were determined for minced meat, hamburgers, nuggets, white sausages, red sausages, escalope, and roll-ups. S. aureus isolates were tested for susceptibility to twenty antimicrobials of veterinary and human clinical significance (disc diffusion method, CLSI). Average microbial loads (log10 cfu/g) ranged from 2.63 ± 0.80 (enterococci) to 6.66 ± 1.09 (psychrotrophs). Average APCs (6.44 ± 1.16 log10 cfu/g) were regarded as acceptable according to EU microbiological criteria. The type of product had an influence (P < 0.05) on microbial loads, samples of escalope showing the highest counts for most microbial groups. Two-thirds (66.7%) of the samples tested harbored S. aureus. All the S. aureus isolates were multi-resistant (to between three and fifteen antibiotics). The greatest prevalence of resistance was shown for ampicillin, oxacillin, penicillin G, ceftazidime, and nalidixic acid. The results of this study show that poultry-based meat preparations present high microbial loads and are a major reservoir of antibiotic-resistant S. aureus strains. This highlights the need for correct handling of such foodstuffs with a view to reducing risks to consumers.