Survival of enteroaggregative Escherichia coli and Vibrio cholerae in frozen and chilled foods

Abstract

Introduction: Enteroaggregative Escherichia coli (EAEC) and Vibrio cholerae are common bacteria that infect people in developing countries. Nowadays, food preservation by freezing and refrigeration are very common practices that extend the shelf life of food products. Unfortunately, EAEC and V. cholerae are suspected to survive at low temperatures. Methodology: Various foods and beverages used as samples were artificially inoculated with EAEC and V. cholerae pure colonies and incubated at room temperature (27°C), refrigeration temperature (4°C), and frozen temperature (-20°C) for one week, two weeks, one month, two months, and three months. The survival of these bacteria was confirmed by polymerase chain reaction (PCR) with specific primers to detect their virulence genes (aggR for EAEC and toxR for V. cholerae) that represent the presence of these bacteria. Results: This study showed that EAEC was able to survive in all food samples used in this study for at least three months under room temperature, refrigeration temperature, and frozen temperature. V. cholerae had poor survival in almost all food samples over two months under room temperature and over three months under refrigeration temperature. V. cholerae was able to survive in all food samples for at least three months under frozen temperature. Conclusions: The survival of EAEC and V. cholerae in this study should increase our awareness of how hazardous these bacteria are. Therefore, in order to improve food safety and hygiene, advanced preservation and sterilization methods should be discovered to prevent contamination with and survival of EAEC and V. cholerae.

Molecular characterization of Vibrio species isolated from dairy and water samples

“…Tahoun et al 23 , Sharma et al 24 , and Islam et al 25 also found higher results. This is corroborated by findings from Waturangi et al 26 who found that V. cholerae could survive for at least three months in all items tested, including UHT milk and ice cream that was kept in a freezer.…”

Report of the Scientific Committee of the Spanish Agency for Food Safety and Nutrition (AESAN) on the microbiological criteria for Vibrio cholerae, as additional control measures at border control posts, applicable to imported frozen prawns and other fishery products

“…In raw shrimp with an initial count of 5 log CFU/g, a survival of between 4 and 9 days was observed at 5 and 10 ºC, respectively (Pesigan et al, 1967). In freezing, a V. cholerae survival greater than 3 months has been verified according to temperature (ICMSF, 1996) (Waturangi et al, 2015). In fresh foods, including freshwater fish, V. cholerae O1 remains viable for up to 90 days at -5 ºC and up to 30 days at -25 ºC.…”

OPTIMIZATION OF MOLECULAR DETECTION FOR Vibrio cholerae and PATHOGENIC Escherichia coli USING MULTIPLEX PCR

“…The sensitivity of the primes was tested with serial of dilution of the V. cholerae and E. coli (EHEC and ETEC) genomics, which was serially diluted from 10 ng; 5 ng; 1 ng; 0.5 ng; 0.25 ng and 10 ng; 5 ng; 2 ng; 1 ng; 0.5 ng; 0.1 ng, respectively. Limit of detection was determined with the lowest DNA concentration that gives clear bands (Waturangi, et al, 2015). Specifically, for V. cholerae specificity evaluation was performed in order to confirm whether primer pairs amplify only with the targeted bacteria and do not cross-react with DNA from other species.…”

“…Each pathogenic bacterium (V. cholerae, ETEC, and EHEC) were cultured in LB medium for overnight at 37°C using orbital shaker incubator at 120 rpm. Then, 5 mL of drinking water samples were inoculated with 1 mL (0.5 McFarland) of the bacteria suspension for artificial contamination purpose (Waturangi, et al, 2015). Subsequently, the samples were incubated using orbital shaker for 24 hours at 120 rpm in three different temperatures (28 o C, 4 o C, and -20 o C).…”