diff --git a/consumer/rabbitmq/consumer.go b/consumer/rabbitmq/consumer.go
index 728a9cd..5862e1c 100644
--- a/consumer/rabbitmq/consumer.go
+++ b/consumer/rabbitmq/consumer.go
@@ -290,7 +290,8 @@ func buildMessage(consumerMeta map[string]interface{}, receivedMsg amqp.Delivery
 	return msg, nil
 }
 
-func (r *rabbitMQ) requeueMessage(consumerMeta map[string]interface{}, receivedMsg amqp.Delivery) func(ctx context.Context, delayFn goqueue.DelayFn) (err error) {
+func (r *rabbitMQ) requeueMessage(consumerMeta map[string]interface{},
+	receivedMsg amqp.Delivery) func(ctx context.Context, delayFn goqueue.DelayFn) (err error) {
 	return func(ctx context.Context, delayFn goqueue.DelayFn) (err error) {
 		if delayFn == nil {
 			delayFn = goqueue.DefaultDelayFn
diff --git a/publisher/option.go b/publisher/option.go
index 64b6a88..b474ae4 100644
--- a/publisher/option.go
+++ b/publisher/option.go
@@ -1,6 +1,13 @@
 package publisher
 
-import "github.com/bxcodec/goqueue"
+import (
+	"github.com/bxcodec/goqueue"
+	headerVal "github.com/bxcodec/goqueue/headers/value"
+)
+
+const (
+	DefaultContentType = headerVal.ContentTypeJSON
+)
 
 // Option define the option property
 type Option struct {
diff --git a/publisher/rabbitmq/publisher.go b/publisher/rabbitmq/publisher.go
index 4f8cf5a..8ac58c6 100644
--- a/publisher/rabbitmq/publisher.go
+++ b/publisher/rabbitmq/publisher.go
@@ -41,6 +41,9 @@ func New(
 }
 
 func (r *rabbitMQ) Publish(ctx context.Context, m goqueue.Message) (err error) {
+	if m.ContentType == "" {
+		m.ContentType = publisher.DefaultContentType
+	}
 	publishFunc := middleware.ApplyPublisherMiddleware(
 		r.buildPublisher(),
 		r.option.Middlewares...,
@@ -79,7 +82,6 @@ func (r *rabbitMQ) buildPublisher() goqueue.PublisherFunc {
 
 		m.Headers = headers
 		m.ServiceAgent = headerVal.RabbitMQ
-		m.ContentType = headerVal.ContentType(m.ContentType)
 		m.Timestamp = timestamp
 		m.ID = id
 		data, err := goqueue.GetGoquEncoding(m.ContentType).Encode(ctx, m)