Microbiological status of some commonly available food items and the effects of microwave oven heat on the existence microflora

Abstract

Foods are the major source of energy and nutrition for all the living organisms. Measuring food safety and security is a vital concern nowadays. The present study attempted to evaluate a complete microbiological profile of some popular food items collected from different restaurants along with their drug-resistant profile. The main focus of this study was to evaluate the efficacy of 60 seconds microwave oven heat on the growth of microorganisms present in the collected food items. Presence of bacterial and fungal microbiological profiling of the food items and their drug-resistant pattern were determined through conventional cultural, biochemical and Kirby Bauer methods. After that, the food was heated in the microwave oven for 60 seconds. All the food items (chicken sandwich, French pizza, chicken pie, pasta, hot dog) were found to be highly contaminated with total viable bacteria and fungus up to 107CFU/g while the pathogenic bacteria such as Escherichia coli, Staphylococcus spp., Pseudomonas spp. was estimated up to 106CFU/g. After 60-second microwave oven heat treatment, the existence microbial load was significantly reduced. Meanwhile, fecal coliform was only detected in chicken sandwich before the heat treatment (102CFU/g) but that was completely eliminated by heat treatment. Staphylococcus spp. and Pseudomonas spp. were found in untreated chicken pie, pasta and French pizza samples although after heat treatment the growth was 100% eliminated. Only in chicken sandwich, 2-log reduction of Staphylococcus spp. was notified after 60-second heat. Moreover, the identified bacteria were found to be 100% resistant against commonly used antibiotics but only streptomycin (10 µg), azithromycin (15 µg) and gentamycin (10 µg) were found as effective drugs against all the isolates. The presence of resistant strain in food is very alarming which indicates the poor management set up and lack of proper legislation in food sector. However, the 60-second microwave oven heat treatment was so effective to reduce the substantial amount of bacteria.

A review of emerging applications of ultrasonication in Comparison with non-ionizing technologies for meat decontamination

“…When microwaves come into contact with meat, they are absorbed by water molecules owing to the interaction between the electromagnetic field and dipole nature of the water molecules. The microbiological profile and drug resistance were evaluated for popular restaurant food items, such as chicken sandwiches, chicken pies, hot dog French pizza, and pasta [32] . All food items had high levels of TVC, fungi, E. coli , Staphylococcus spp., and Pseudomonas spp.…”

“…All food items had high levels of TVC, fungi, E. coli , Staphylococcus spp., and Pseudomonas spp. The 60-second microwave oven heat treatment reduced the microbial load and eliminated the fecal coliforms [32] . Microwave technology can be optimized by exploring lower power levels, shorter treatment times, or incorporating combination treatments with other non-thermal technologies to achieve a balance between safety and quality.…”