In order to do this you need to use a PREFIX-list, as shown here:

router eigrp 100
network 172.16.0.0
distribute-list prefix test in
auto-summary
no eigrp log-neighbor-changes
!
ip prefix-list test seq 5 permit 172.16.1.0/24

This allows only the 172.16.1.0/24 prefix and therefore denies 172.16.1.0/28.

NOTE: The use of ACL and distribute-list under EIGRP does not WORK in this case. This is because ACLS do not check the mask, they just check the network portion. Since the network portion is the same, when you allow 172.16.1.0/24, you also allow 172.16.1.0/28.

In order to do this you need to use a prefix-list, as shown here:

router eigrp 100
network 172.16.0.0
distribute-list prefix test in
auto-summary
no eigrp log-neighbor-changes
!
ip prefix-list test seq 5 permit 172.16.1.0/24

This allows only the 172.16.1.0/24 prefix and therefore denies 172.16.1.0/28.

Note: The use of ACL and distribute-list under EIGRP does not work in this case. This is because ACLs do not check the mask, they just check the network portion. Since the network portion is the same, when you allow 172.16.1.0/24, you also allow 172.16.1.0/28.