E. coli found in 54% of retail chicken samples in Kerala; cross-contamination risk high, warns study

Kochi: Food safety concerns have resurfaced in Kerala following new findings on bacterial contamination in poultry. A new study has found that over half of retail chicken samples tested in the state were contaminated with E. coli, many of them resistant to multiple antibiotics.

The study titled 'Multidrug-resistant Escherichia coli in retail chicken meat: A cross-sectional study from Kerala, India' was conducted by Binsy Mathew, Latha C, Sunil B, Sethulekshmi C, Radhika G and Sivaraman G K. The researchers analysed 600 chicken samples collected between 2019 and 2023 from six districts: Kozhikode, Palakkad, Thrissur, Ernakulam, Kollam and Pathanamthitta. E. coli was detected in 54.17% of the samples, indicating widespread contamination in retail poultry.

As per the study, 8% of the isolates carried virulence genes associated with typical enteropathogenic E. coli (EPEC), a strain known to cause diarrhoeal illness, particularly in children. Researchers also identified other diarrhoeagenic strains, including enteroaggregative and enteroinvasive E. coli, though at lower rates.

Nearly half of the samples tested, 49.28%, were found to be multidrug-resistant, meaning they could survive treatment with more than three classes of antibiotics. The Multiple Antibiotic Resistance (MAR) index ranged from 0 to 0.89, with over 63% of the isolates recording high scores, suggesting they originated from environments where antibiotics are frequently used.

When tested against nine antibiotics recommended by the World Health Organisation (WHO), the bacteria showed high resistance levels. More than half were resistant to nalidixic acid (55.07%). Resistance was also significant to trimethoprim (46.01%), co-trimoxazole (40.58%), tetracycline (39.86%) and ampicillin (36.59%), raising concerns about the effectiveness of commonly used drugs.

The World Health Organisation has identified antimicrobial resistance (AMR) as one of the biggest global threats to public health, food security and development.

According to Dr Binsy Mathew, Department of Veterinary Public Health, College of Veterinary and Animal Sciences, Thrissur, several factors contribute to E. coli colonisation in poultry, including the increasing use of growth promoters, incomplete antibiotic courses in diseased birds, and contaminated water. She noted that such contamination was rarely detected in chicken earlier and said its presence now points to improper slaughtering practices. "This is a serious public health concern. There needs to be immediate changes in the way chicken is slaughtered," she told Onmanorama.

She also warned about cross-contamination at the household level. "When chicken is brought home, bacteria can spread from one vessel to another. The water used to wash the meat can splatter, and droplets may land on nearby fruits and other foods, leading to contamination," she added.

The study highlights the potential public health risks posed by antimicrobial-resistant bacteria entering the food chain through poultry. Experts warn that resistant bacteria in food animals can transfer resistance genes to human pathogens, complicating treatment outcomes.

"Often, when a person is infected with E. coli, the illness is self-limiting, with symptoms such as diarrhoea that usually resolve within a week. However, certain strains, such as Enterohemorrhagic E. coli (EHEC), can be dangerous," Dr Binsy said.

Kerala's poultry sector has expanded rapidly in recent years, with many consumers preferring freshly slaughtered chicken from wet markets. However, variations in slaughtering and hygiene practices may increase the risk of contamination. The findings underscore the need for strengthened surveillance systems, stricter regulation of antibiotic use in poultry farming, and improved hygiene practices in retail meat handling.