* Workers object to hiring practices at private terminals
* Ports brace for nationwide union demonstrations Thursday
SAO PAULO, July 10 (Reuters) - Dock workers at Brazil's key shipping port of Santos, the largest in South America, stopped a strike over port reform early on Wednesday but plan to walk off the job again on Thursday in support of a broader union protest.
Port authorities said Wednesday's strike prevented the loading of some 13 container ships for a few hours, but mechanized bulk cargo shipments, such as soybeans and corn, were not affected.
The National Stevedores Association in Brasilia said workers at other ports had decided against a July 10 strike and would instead join other industrial unions planning a nationwide walkout on Thursday, July 11.
Dock workers are afraid a drive to privatize port terminals under legislation passed in May will lead to a loss of jobs and benefits because private operators would not have to hire through the centralized agency known as OGMO.
They say Embraport, a new $1.2 billion private container terminal at Santos owned by local infrastructure group Odebrecht Transport, the United Arab Emirates' DP World and trading company Coimex, is not hiring through OGMO.
The port strike comes on the heels of a protest by truck drivers that slowed grain deliveries at major ports last week and diverse nationwide demonstrations in June that drew over 1 million protesters at their peak.
Brazil is currently exporting record soy, corn and sugar crops. Stevedores at Santos last held a two-day strike in May.
Typically, bulk cargo such as grains are less affected by labor stoppages because they require fewer workers. The movement of container goods with perishables such as coffee, bagged sugar and meats are more vulnerable.