Maybe a better way would be to stop selling them food. We still want to buy Apple products, but they need to buy food.
It's ok to sell food, and every dollar they spend of food is one less for ballistic missiles.
It's also stupid. What did the PRC do in response to US tariffs? Voluntarily stop buying US food.
The PRC doesn't need US food, it can buy what it needs elsewhere (e.g. soybeans from Brazil instead of Illinois).
Having said that: iron ore, not food. As a thought experiment: it would be most effective to target China's main imports: integrated circuits, oil, iron ore, ... [1]
ICs are mainly used in exports so limited domestic impact, oil can be had from any number of despotic partners, iron ore on the other hand...
Most of China's iron ore comes from Australia, and there is currently no alternative. If Australia refused to sell iron ore to China it would really screw up China's economy [2] (and Australia's):
Proof of China's dependence on Australian iron ore is in the current sanctions the CCP is placing on Australia, as payback for Australia not kowtowing to the CCP [3]. The result has been a major loss of face for the CCP, in that it has made Australia's economy more resilient by forcing diversification of its export markets, in the process reducing CCP's influence, simultaneous with Australia's exports to China continuing to break new records [4]. No one is under any illusions that the CCP would dearly like to stop iron ore imports from Australia, but it can't. Eventually the CCP may be able to wean China off Australian iron ore, but chances are it will happen so slowly that Australia will have time to find new markets.
Yes, Australia could screw China, as the CCP is trying to do to Australia, but that would only reduce Australia to the same level as the CCP and ruin Australia's goodwill with the Chinese people (the CCP is not China).
[1] https://www.google.com/search?q=china%27s+biggest+imports
[2] https://www.hellenicshippingnews.com/what-would-happen-if-ch...
[3] https://www.smh.com.au/world/asia/if-you-make-china-the-enem...
[4] https://www.abc.net.au/news/2021-01-26/australian-economy-co...
Then China would impose tit-for-tat tarrifs - imagine they slapped a 100% tariff on ICs.