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ARS Home » Northeast Area » Wyndmoor, Pennsylvania » Eastern Regional Research Center » Food Safety and Intervention Technologies Research » Research » Publications at this Location » Publication #300206
Title: Survival, injury and inactivation of Escherichia coli 0157:H7, salmonella and aerobic mesophilic bacteria in apple juice and cider amended with nisin-edta

Author
item Ukuku, Dike
item Geveke, David
item Mukhopadhyay, Sudarsan
item Olanya, Modesto
item Juneja, Vijay

Submitted to: Journal of Food Processing and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/16/2014
Publication Date: 10/27/2014
Citation: Ukuku, D.O., Geveke, D.J., Mukhopadhyay, S., Olanya, O.M., Juneja, V.K. 2014. Survival, injury and inactivation of Escherichia coli 0157:H7, salmonella and aerobic mesophilic bacteria in apple juice and cider amended with nisin-edta. Journal of Food Processing and Technology. 5:385.

Interpretive Summary: Foodborne illnesses associated with consumption of bacteria contaminated fruit and vegetable juices continue to be a problem for the juice industries and consumers alike. Minimally processing juice using natural antimicrobial (nisin and ethylenediaminetetraacetic acid (EDTA)) compounds was investigated. Apple juice and cider was inoculated with human bacterial pathogens (Escherichia coli O157:H7 and Salmonella) at 4 log CFU/ml. The inoculated apple cider (pH 3.9) and apple juice (pH 3.6) were amended with the combination of nisin (500 IU/ml) + EDTA (0.02 M) and stored at 5 and 10 deg C for 6 days as well as 23 deg C for 24 h. Periodically, bacteria that survived treatment were monitored during storage. Populations of naturally occurring bacteria of apple juice and cider increased while the inoculated populations of E. coli O157:H7 and Salmonella cells slightly declined in control samples during storage at 5 deg C for 6 days. In treated juices, Escherichia coli O157:H7 and Salmonella bacteria were in some cases below detection during similar storage at 5 deg C for 6 days. This study suggests that addition of nisin + EDTA combination to an unpasteurized apple cider or apple juice improves the microbial safety and reduces the risk of foodborne illnesses.

Technical Abstract: For health reasons, people are consuming fresh juices or minimally processed fruit and vegetable juices, thereby, exposing themselves to the risk of foodborne illness if such juices are contaminated with bacteria pathogens. Behavior of aerobic mesophilic bacteria, Escherichia coli O157:H7 and Salmonella cells at 4log CFU/ml in apple cider (pH 3.9) and apple juice (pH 3.6), amended with the combination of nisin (500 IU/ml) + ethylenediaminetetraacetic acid (EDTA, 0.02 M) and stored at 5 deg C and 10 deg C for 6 days as well as 23 deg C for 24 h was investigated. Populations of aerobic mesophilic bacteria of apple juice and cider increased while E. coli O157:H7 and Salmonella cells slightly declined in control samples during storage at 5 deg C for 6 days. There was significant (p<0.05) inactivation of Escherichia coli O157:H7 and Salmonella bacteria in apple juice and cider amended with nisin+EDTA during similar storage at 5 deg C for 6 days, and in some cases the populations were below detection (<10 CFU/ml) for Salmonella and E. coli O157:H7 cells. Generation time for aerobic mesophilic bacteria in control apple juice and cider without inoculated populations of human bacterial pathogens stored at 5 deg C was 27.59 min and 30.85 min, respectively but averaged 30.61 and 31.83 in the presence of inoculated pathogens. In samples stored at 23 deg C for 24 h, the generation time and the specific growth rate for aerobic mesophilic bacteria, Escherichia coli O157:H7 and Salmonella cells were significantly (p<0.05) different within and between juices. This study suggests that addition of nisin +EDTA combination to a freshly prepared unpasteurized apple cider or apple juice improves the microbial safety of the juices and reduces the risk of foodborne illnesses.