He's referring to buddhist cuisine. Buddhist philosophy states that pungent herbs or spices alert your senses and fog your brain, preventing mindfulness.
From the wiki:
>In addition to the ban on garlic practically all Mahayana monastics in China, Korea, Vietnam and Japan specifically avoid eating strong-smelling plants, traditionally asafoetida, shallot, mountain leek and Allium chinense, which together with garlic are referred to as wǔ hūn (五荤, or 'Five Acrid and Strong-smelling Vegetables') or wǔ xīn (五辛 or 'Five Spices') as they tend to excite senses. This is based on teachings found in the Brahamajala Sutra, the Surangama Sutra and the Lankavatara Sutra (chapter eight). In modern times this rule is often interpreted to include other vegetables of the onion genus, as well as coriander. The origins of this additional restriction is from the Indic region and can still be found among some believers of Hinduism and Jainism. Some Taoists also have this additional restriction but the list of restricted plants differs from the Buddhist list.
I actually learned this from Chef's Table S3E01 which is a great intro to Buddhist Cuisine if you're interested in learning more. It seems ironic that the five "pungent" herbs are avoided but fermented vegetables are not.