Potentiating the Heat Inactivation of Escherichia coli O157:H7 in Ground Beef Patties by Natural Antimicrobials

Abstract

Escherichia coli O157: H7 (EHEC) is a major foodborne pathogen largely transmitted to humans through the consumption of undercooked ground beef. This study investigated the efficacy of two food-grade, plant-derived antimicrobials, namely rutin (RT), and resveratrol (RV) with or without chitosan (CH) in enhancing EHEC inactivation in undercooked hamburger patties. Further, the effect of aforementioned treatments on beef color and lipid oxidation was analyzed. Additionally, the deleterious effects of these antimicrobial treatments on EHEC was determined using scanning electron microscopy (SEM). Ground beef was inoculated with a five-strain mixture of EHEC (7.0 log CFU/g), followed by the addition of RT (0.05%, 0.1% w/w) or RV (0.1, 0.2% w/w) with or without CH (0.01% w/w). The meat was formed into patties (25 g) and stored at 4°C for 5 days. On days 1, 3, and 5, the patties were cooked (65°C, medium rare) and surviving EHEC was enumerated. The effect of these treatments on meat color and lipid oxidation during storage was also determined as per American Meat Science Association guidelines. The study was repeated three times with duplicate samples of each treatment. Both RT and RV enhanced the thermal destruction of EHEC, and reduced the pathogen load by at least 3 log CFU/g compared to control (P < 0.05). The combination of RT or RV with CH was found to be more effective, and reduced EHEC by 5 log CFU/g (P < 0.05). EHEC counts in uncooked patties did not decline during storage for 5 days (P > 0.05). Moreover, patties treated with RV plus CH were more color stable with higher a∗ values (P < 0.05). SEM results revealed that heat treatment with antimicrobials (CH + RV 0.2%) resulted in complete destruction of EHEC cells and extrusion of intracellular contents. Results suggest that the aforementioned antimicrobials could be used for enhancing the thermal inactivation of EHEC in undercooked patties; however, detailed sensory studies are warranted.

Activating sodium alginate‐based edible coating using a dietary supplement for increasing the shelf life of rainbow trout fillet during refrigerated storage (4 ± 1 °C)

“…Previous researchers also identified antioxidant activity of RE, reporting that compounds with phytoalexin origin such as RE are potent antioxidants (Gerszon et al, ; Gülçin, ; Iuga et al, ). No significant difference was observed between RE and control groups in TBARS value of ground beef patties based on the results of Surendran Nair et al (). Their result is inconsistent with the finding of this study.…”

“…They reported inhibiting E. coli by RE, mediated by site‐specific oxidative damage to the cell membrane as the primary event. Surendran Nair et al () showed potentiating the heat inactivation of E. coli O157:H7 in ground beef patties by RE (0.1 and 0.2%). They suggested RE to be used for increasing the thermal inactivation of EHEC in undercooked patties.…”

“…Acting as a potent antioxidant, RE increases nitric oxide production, high‐density lipoprotein cholesterol, as well as cardio protective agent and inhibits platelet aggregation. Also, various experimental studies have proved that RE is a neuroprotective, anti‐inflammatory, chemo‐preventive, and antiviral agent (Gerszon et al, ; Gülçin, ; Surendran Nair et al, ).…”

Challenges and opportunities related to the use of chitosan as a food preservative

“…The addition of chitosan at a concentration of 0·01% (w/w) enhanced the thermal inactivation of E. coli O157:H7 (EHEC) in ground beef by 1·5 log (CFU per g) (Surendran Nair et al . ). Chitosan at a concentration of 0·1% (w/v) acted synergistically with pressure treatment of apple juice to inactivate E. coli (Kumar et al .…”

Application of Surfactant Micelle-Entrapped Eugenol for Prevention of Growth of the Shiga Toxin-Producing Escherichia coli in Ground Beef

“…Application of commercial herb extract-containing products to STEC-inoculated beef trimmings, two rounds of grinding, and up to seven days’ refrigerated (4 °C) storage, produced reductions of 0.1 to 0.2 log 10 CFU/g in STEC numbers [ 14 ]. More recently, researchers reported that the application of 0.05% or 0.1% rutin, or 0.1% or 0.2% resveratrol, did not reduce E. coli O157:H7 in ground beef patties during refrigerated storage, but did enhance reductions of the pathogen upon subsequent cooking to an internal temperature of 65 °C [ 15 ]. The use of encapsulation strategies, such as surfactant micelles, has been described as providing opportunity for enhanced transport and delivery of entrapped compounds to foodborne microbes in both animal- and plant-based foods [ 16 , 17 , 18 ].…”