It depends on how much that commodity plays a role in the overall economy of that country.

“What are the implications of targeting headline inflation in African economies?” This is an interesting question and sadly there are few good answers, at least that I am aware of. You have stated it a bit general, so I am focusing below on the food price angle that you have raised.

In many African countries, official CPI estimates are based on a handful of urban areas so the possible bias runs much deeper; large shares of the populations live in rural areas that are generally poorer. In turn, rural areas may rely on different methods of production and subsequently follow different growth paths and thus food price development all together. While general inflation typically depends on changes in money supply and the demand for money, it may also be heavily affected by exchange rate shocks and general external demand for currency and produce, particularly in emerging and developing markets. This is highlighted in the most recent world bank economic prospects report. Good examples of the impacts of externally driven food price inflation are documented in the literature around the commodity boom or “world food price crisis 07-08”. Details can be found int the world bank economic prospects reports of the relevant time periods, but also in literature around food security.

There have been a few attempts at teasing out the effects of changes in price ratios and, generally, there is possible room for poverty shocks even if there is no considerable inflation in general. For example, if the price of food increases relative to non-food, this may signal food scarcity without general inflation as a requirement. Particularly because, as you mention, expenditures of poorer households can be dominated by food items. Furthermore, if the prices of certain commodities that are key from a nutritional standpoint increase relative to the prices of other food items, there can be poverty shocks that run through nutrition channels. This means that developmental policies may not only need to focus on general inflation, but on relative scarcity that in turn would be supported by diverging prices not general inflation. Unfortunately, such granular data does often not exist and price controls may have new undesirable effects.

So, while there are arguments to focus on more specific definitions of inflation, another question that is possibly relevant is whether focusing on general inflation is desirable from a developmental perspective. The answer is, of course, yes - in my view- because the extremes of many of the aspects detailed above may be implied by, or move together with, general price development. Moreover, if general inflation is high, people are encouraged to spend in the short run and savings may rapidly lose value. While increased spending may boost an economy in the short run, there are also arguments, particularly relevant in the context of fragile economies, that irreversibly liquidating of livelihood assets - possibly at undesirable price levels - increases the vulnerability of households to future economic shocks.

I hope this helps, it remains a a topic about much can still be said.

PRICE SHOCK should not have any effect on policy making. By definition shock is a temporary event; after a while the price will return to the long-rum equilibrium; hence, integrated effects of the shock.

PRICE CHANGE is a price drifting from it equilibrium point and does not return. In such a case, policy makers may consider---among other factors---if such change affects input cost and the health of the economy.

I guess it also depends on the source of shock - central banks generally do not respond to supply side shocks but if the rise is led by a demand side that would definitely mean tighter policies.

Tober, S., Zimmermann, T. Monetary policy and commodity price shocks. Intereconomics 44, 231–237 (2009). https://doi.org/10.1007/s10272-009-0300-4

Abstract

Against the background of the dramatic changes in the prices of oil and other raw materials in the recent past, this paper analyses the effects of commodity price shocks in a New Keynesian model. The focus is on the central bank’s choice of inflation target and the degree of real wage rigidity. It turns out that using core inflation rather than headline inflation is the superior strategy. Targeting expected headline inflation, as practised by most central banks, is a viable practical alternative to the core inflation target. A communication strategy that places greater emphasis on underlying and expected inflation could serve to anchor inflation expectations.

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Imo, the Taylor rule seems still to play a great role, with respect to your query, dear Oluseun Ishola , i.e. it suggests how central banks should change interest rates to account for inflation and other economic conditions.

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Stephen A. O'Connell. (2012). "Inflation Targeting In Africa". Oxford Companion To The Economics Of Africa. 359-364. https://works.swarthmore.edu/fac-economics/256

On balance, the evidence suggests that inflation targeters achieve more stable and somewhat lower inflation rates than non-targeters, with little or no sacrifice in terms of employment and output; and that external shocks are somewhat less likely to destabilize expectations . The policy literature has accommodated this ever more impressive track record by gradually softening its concern for preconditions.

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Imo, food and energy are not included in core inflation because their prices are volatile. It makes headline inflation a more volatile measure than core inflation;

the headline inflation figure includes inflation in a basket of goods that includes commodities like food and energy. Headline inflation, being more volatile, cannot be used to calculate inflation trends and is often substituted with core inflation to see the direction of the trend. Some economists argue that core inflation or similar measures should be used to design monetary policy. The main argument being that volatility in food and energy prices are short-term fluctuations.

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The most important thing to remember is that inflation is not an act of God, that inflation is not a catastrophe of the elements or a disease that comes like the plague. Inflation is a policy. Inflation is the fiscal complement of statism and arbitrary government. It is a cog in the complex of policies and institutions which gradually lead toward totalitarianism . Economic history is a long record of government policies that failed because they were designed with a bold disregard for the laws of economics Ludwig von Mises (2013). “The Theory of Money and Credit”, p.428, Skyhorse Publishing, Inc.