Investigation of the antimicrobial properties of nanoclay and chitosan based nanocomposite on the microbial characteristics of Gouda cheese.

BACKGROUND AND OBJECTIVES: In recent years, active packaging has been introduced as a new method to better preserve food. Chitosan and nanoclay have been used for preparation of an active nanocomposite with respect to their antimicrobial properties to investigate its effects on the microbial limitation in Gouda cheese. MATERIALS AND METHODS: Nanoclay film, chitosan film, chitosan-based nanocomposites and nanoclay-based nanocomposites were prepared and their antimicrobial properties were evaluated to the microbial limitations of Gouda cheese consist of coliforms, Escherichia coli, Salmonella spp., coagulase-positive Staphylococcus, mold and yeast by agar diffusion method. RESULTS: The results indicated, the best antimicrobial effect belonged to nanocomposite film with the composition of chitosan 3 wt% by adding nanoclay 1 wt%, which can prevent microbial characteristics of Gouda cheese. CONCLUSION: The chitosan and nanoclay nanocomposite had excellent antibacterial activity and performed well against microbial limitations (coliforms, E. coli, Salmonella spp., coagulase-positive Staphylococcus, mold and yeast) of Gouda cheese. Therefore, the nanocomposite may be possibly used as a surface coating in addition to Gouda cheese as well as similar cheeses and other food to enhance microbial characteristics and extend shelf life.

Isolation and identification of bacteria from paperboard food packaging.

BACKGROUND AND OBJECTIVES: Paper and paperboard packaging play an important role in safety and quality of food products. Common bacteria of paper and paperboard food packaging could grow due to specific conditions included humidity, temperature and major nutrition to contaminate the food. The purpose of this research was to investigate numbers and the types of bacteria in the food packaging paperboard. MATERIALS AND METHODS: The surface and the depth of the each paperboard sample were examined by the dimension of one cm(2) and one gram. The paperboard samples were randomly collected from popular confectionaries and fast food restaurants in Tehran, Iran. RESULTS: The results indicated the range of 0.2×10(3) to >1.0×10(5) cfu/1g bacterial contamination in paperboard food packaging. Also, most detected bacteria were from spore forming and family Bacillaceae. CONCLUSION: The bioburden paperboard used for food packaging showed high contamination rate more than standard acceptance level.