Submitted to: Journal of Food Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/20/2009
Publication Date: 9/14/2009
Citation: Ravishankar, S., Zhu, L., Olsen, C.W., Mc Hugh, T.H., Friedman, M. 2009. Edible Apple Film Wraps Containing Plant Antimicrobials Inactivate Foodborne Pathogens on Meat and Poultry Products. Journal of Food Science. 74(8):M440-M445.
Interpretive Summary: Present day consumers prefer natural products over synthetic additives. Natural products derived from plants have gained popularity in recent years as antimicrobials in food processing to render a safe food product for the consumer. Surface contamination of many processed food products is an important safety issue for many food processors. Antimicrobials that can act on the surface of a food product can reduce surface contamination and could help solve this issue. Salmonella enterica is an important foodborne pathogen, being the leading cause of gastrointestinal illness worldwide. Patients can be asymptomatic carriers for weeks after the infection. Poultry and egg products have been predominantly implicated in foodborne Salmonellosis. Escherichia coli O157:H7 is a foodborne pathogen of concern in immuno-compromised individuals such as the elderly, young children and pregnant women. The pathogen can be deadly, if proper and timely treatment is not given to the victims. E. coli O157:H7 has been implicated in a variety of food products, including apple cider, produce, hamburgers and poultry products. Listeria monocytogenes is also a foodborne pathogen of concern in immuno-compromised individuals and pregnant women. Left untreated, the organism can cause mild flu-like illness and can enter the bloodstream causing meningitis and encephalitis. It can also adversely affect the fetus causing abortions and stillbirths. L. monocytogenes has caused outbreaks following consumption of contaminated dairy products and ready-to-eat meats. Surface contamination of ready-to-eat meat and poultry products with L. monocytogenes is an important food safety issue. The incorporation of antimicrobials in edible films could serve as an additional barrier for surface contaminating microorganisms. The objective of the present study was to investigate the effects of carvacrol and cinnamaldehyde incorporated into apple-based edible films against S. enterica and E. coli O157:H7 on contaminated raw chicken breast surfaces, and against L. monocytogenes on ham surfaces. This study demonstrates the potential of edible apple films containing plant antimicrobials to inactivate pathogenic bacteria on contaminated poultry chicken breasts and ham. Food processors and consumers are expected to welcome the described approach to improve food safety.
Technical Abstract: As part of an effort to discover new ways to improve microbial food safety, we evaluated apple-based edible films containing plant antimicrobial compounds for their activity against pathogenic foodborne bacteria on meat and poultry products. Salmonella enterica or Escherichia coli O157:H7 (107 CFU/g) cultures were surface-inoculated on raw chicken breasts and Listeria monocytogenes (106 CFU/g) was inoculated on the surface of ham. The meat and poultry products were then wrapped with apple-based edible films containing three concentrations (0.5, 1.5 and 3%) of cinnamaldehyde or carvacrol. Following incubation at either room temperature (23°C) or at 4°C for 72h, samples were stomached in buffered peptone water, diluted and plated for enumeration of survivors. The results showed that the antimicrobial films exhibited concentration-dependent activities against the foodborne pathogens tested. On chicken breasts at 23°C, films with 3% antimicrobial concentrations showed the highest reductions (4-7.8 log CFU) of both S. enterica and E. coli O157:H7 compared to control samples. Films containing 1.5% and 0.5% antimicrobials showed 2.4-4.4 and 1.5-2.8 log CFU reductions, respectively. At 4°C, carvacrol exhibited stronger activity compared to cinnamaldehyde. Films with 3, 1.5 and 0.5% carvacrol reduced the bacterial populations by about 4, 1.6-4, and 0.7-1 log CFU, respectively. Films with 3 and 1.5% cinnamaldehyde-induced 1.2-3.5 and 1-1.3 log CFU reductions, respectively. For L. monocytogenes on ham, carvacrol films showed better activity than cinnamaldehyde films and the activity was better at 23°C than at 4 °C. Added antimicrobials had minor effects on physical properties of the films. The results suggest that the food industry and consumers could use these films as wrappings to control surface contamination by pathogenic microorganisms.