Rising commodities prices led both Smithfield Foods Inc. (NYSE: SFD), the nation's largest pork producer and processor, and poultry producer Sanderson Farms Inc. (NASDAQ: SAFM) to report quarterly losses on Tuesday.

Smithfield Foods said it lost $12.6 million, or 9 cents per share, in its fiscal first quarter due in part to a $20.1 million write-down in the value of commodity contracts. The Smithfield, Va.-based company had reported a profit of $54.6 million, or 41 cents per share, a year ago.

Revenues rose 20% to $3.14 billion in the quarter. Analysts surveyed by Thomson Reuters had forecast a loss of 4 cents per share on $2.87 billion in sales.

In addition to hurting from high costs for such ingredients as grain and fuel, Smithfield also faces an oversupply of meat on the market, which is keeping prices for pork lower. To help push prices up, meat producers such as Smithfield have announced intentions to cut supply.

Shares of Smithfield fell 88 cents, or 3.7%, to $22.71 in morning trading. That's up from a 52-week low of $16.61 in early July, but shares have fallen about 21% since the beginning of the year.

MOST NOTEWORTHY: PSS World Medical (PSSI), Rockwell (ROK), Open Text (OTEX), Sanderson Farms (SAFM) and Mentor (MNT) were today's noteworthy upgrades:

• PSS World Medical (NASDAQ: PSSI) was upgraded to Outperform from Neutral at Robert W. Baird. Baird said the quarter was impacted by one-time items and that core operations remain strong while private label, home care and HCIT initiatives may contribute to substantial margin improvement.
  
• Friedman Billings added Rockwell Automation (NYSE: ROK) to its Top Picks list based on valuation and growth drivers.
  
• Merrill Lynch upped shares of Open Text Corporation (NASDAQ: OTEX) to Neutral from Sell. Kaufman Brothers upgraded shares of the stock to Buy from Hold with a $27 target to reflect the company's better-than-expected Q4 results.
• Sanderson Farms Inc (NASDAQ: SAFM) was upgraded to Strong Buy from Strong Sell on valuation and accelerating sales of the company's poultry products.
  
• The firm upgraded shares of Mentor Corporation (NYSE: MNT) to Buy from Sell given the company's good performance and low risk.

OTHER UPGRADES:

• Cache Inc (NASDAQ: CACH) was upgraded to Buy from Neutral with a $19 target at First Albany and to Outperform from Market Perform at Piper Jaffray.
  
• Gabelli upgraded shares of Diageo (NYSE: DEO) to Buy from Hold.
  
• RBC Capital Markets raised shares of Knology Inc (NASDAQ: KNOL) to Outperform from Sector Perform.
  
• Goldman Sachs upgraded shares of Maxygen Inc (NASDAQ: MAXY) to Neutral from Sell.

Analyst summaries provided by TheFlyOnTheWall.com (subscription required).

MOST NOTEWORTHY: RealNetworks, Inc (RNWK), The Boeing Co (BA), L-3 Communications Holdings (LLL) and Research in Motion (RIMM) were some of today's most notable upgrades:

• Jefferies upgraded RealNetworks, Inc (NASDAQ: RNWK) to Hold from Underperform with an $8 target on valuation.

• JP Morgan raised The Boeing Co (NYSE: BA) and L-3 Communication Holding's (NYSE: LLL) rating to Neutral from Underweight citing valuation.

• Yesterday's "China Effect" on the U.S. markets have created a buying opportunity in Research in Motion Ltd; ThinkEquity upgraded shares of Research in Motion Ltd (NASDAQ: RIMM) to Buy from Accumulate with a $165 target.

OTHER UPGRADES:

• Ciena Corp (NASDAQ: CIEN) was upgraded to Overweight from Neutral at JP Morgan.

• Wachovia upgraded Fresh Del Monte Produce inc (NYSE: FDP) to Market Perform from Underperform based on an improving banana outlook and cost environment.

• Citigroup upgraded Nestle (OTC: NSRGY) to Buy from Hold to reflect the company's improved cash flows.

• Bear Stearns upgraded BEA Systems Inc (NASDAQ: BEAS) to Peer Perform from Underperform.

• Stephens upgraded Sanderson Farms Inc (NASDAQ: SAFM) to Overweight from Equal Weight with a $35 target.

Analyst summaries provided by TheFlyOnTheWall.com (subscription required).