Summary Chitosan–pectin hydrogel beads that trap and release the maximal amount of combined garlic and holy basil essential oils to inhibit food microorganisms were developed based on the central composite design, with chitosan (0.2–0.7% w/v), pectin (3.5–5.5% w/v) and calcium chloride (CaCl2) (5.0–20.0% w/v) contents. The optimal bead consisted of 0.3–0.6% w/v chitosan, 3.9–5.1% w/v pectin and 8.0–17.0% w/v CaCl2, which had a high encapsulation efficiency (62.16–79.06%) and high cumulative release efficiency (31.55–37.81%) after storage at 5 °C for 15 days. Optimal hydrogel beads were packed into a cellulose bag to evaluate antimicrobial activity by the disc volatilisation method. The beads inhibited Bacillus cereus, Clostridium perfringens, Escherichia coli, Pseudomonas fluorescens, Listeria monocytogenes and Staphylococcus aureus but did not affect Lactobacillus plantarum and Salmonella Typhimurium. The oil‐containing beads could potentially be applied in food packaging to inhibit the mentioned microorganisms.

Summary Antimicrobial activity of garlic (Allium sativum L.) and holy basil (Ocimum sanctum L.) essential oils (GEO and HBEO, respectively) was evaluated in liquid vs. vapour phases. Diallyl disulphide and diallyl trisulphide in GEO while eugenol, caryophyllene and methyl eugenol in HBEO were predominant active compounds. Individually, GEO was highly effective in the vapour phase, showing the greatest antimicrobial activity (P ≤ 0.05) against Bacillus cereus and Staphylococcus aureus with complete inhibition, followed by Salmonella typhimurium and Pseudomonas fluorescens, but had no effect on Escherichia coli, Lactobacillus plantarum or Listeria monocytogenes. The combined GEO:HBEO (a 1:1 ratio) at 30 μL demonstrated inhibitive activity against all bacteria tested with complete inhibition against B. cereus and S. aureus. Minimum bactericidal concentration (MBC) of the combined oil was <0.4% v/v, except for P. fluorescens requiring a higher MBC (1.5%, v/v). This study demonstrated potential of the combined GEO:HBEO to be used for food preservation applications.

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Summary Chitosan‐coated pectin beads containing mixed garlic and holy basil essential oils (GEO + HBEO) were prepared to inhibit microbial growth and extend shelf life of chilled stir‐fried pork with basil leaves on rice. The factors affecting release of GEO + HBEO were determined. Increasing environmental relative humidity, temperature and time enhanced a release rate of mixed oils from the beads. Antimicrobial activity of beads was evaluated by disc volatilisation method. Beads, at 2.20 and 4.40 g, could inhibit Bacillus cereus, Clostridium perfringens, Escherichia coli, Pseudomonas fluorescens, Listeria monocytogenes and Staphylococcus aureus. The beads were applied in packaging of chilled stir‐fried pork with basil leaves on rice. During storage, samples containing beads had Total Plate Count (TPC) less than that of the sample without beads. Furthermore, sample without beads had TPC over the limit on Day9, whereas sample with beads had TPC <106 CFU/g until Day24. A sensory triangle test showed that the sample without beads was significant different in appearance, odour and off flavour attributes from the control (sample kept in freezer) on Day5, while the sample with beads was significant different from the control on Day8; therefore, the shelf life based on sensory differences could be extended by 3 days.

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