Prevalence and quantification of Salmonella contamination in raw chicken carcasses at the retail in China

• We quantify contamination loads of Salmonella in 1595 chicken carcasses in China.
• 41.6% of chicken carcasses contaminated and the median load was 4.6 MPN/100 g.
• It observed provincial and monthly variations in prevalence and quantification.
• July and August had 10 times higher loads than rest of other months.
• Chilled carcasses were higher than frozen and freshly slaughtered in prevalence.

The quantitative contamination load of Salmonella in raw chicken carcasses at the retail level in six provinces and cities of China was determined within 1595 carcasses over 12 consecutive months. The overall Salmonella contamination rate was 41.6% and the median load of those contaminated was 4.6 MPN/100 g with 1.8 MPN/100 g as the 25th percentile and 18.0 MPN/100 g as the 75th percentile. There were significant variations in prevalence among carcasses sampled either in different provinces or sampling months. Carcasses collected in August had not only the highest prevalence of contamination (55.8%), but also the highest median (14.0 MPN/100 g) and 75th percentile load (120.0 MPN/100 g) values compared to January with lowest prevalence (26.5%), median (1.5 MPN/100 g) and 75th percentile load (7.6 MPN/100 g). The chilled (55.1%) stored carcasses was significantly higher in prevalence than those frozen (33.5%) and those freshly slaughtered (28.3%), those unpackaged (45.1%) was more likely to be contaminated with Salmonella than those packaged (37.4%). The present study revealed the widely prevalent Salmonella contamination among retail carcasses, indicating a strong potential of the cross-contamination occurred before and/or at the retail level. The study also provided quantitative data for a risk assessment evaluating potential intervention methods to reduce the risk of salmonellosis by consuming chicken meat of Chinese origin.