```python
from fastapi import FastAPI, status, Request
from fastapi.responses import JSONResponse

import helpers
import asyncio

app = FastAPI()


@app.post("/orders")
async def create_order(request: Request):
    data = await request.json()
    item = data.get("item")
    if not isinstance(item, str):
        return JSONResponse(content={"error": "Missing or invalid 'item'"}, status_code=400)

    # Use the async helper for non-blocking audit logging
    await helpers.aappend_audit_line(f"order:{item}")

    return JSONResponse(content={"status": "created"}, status_code=status.HTTP_201_CREATED)
```