Psychrotrophy and foodborne Salmonella

Area of Science:

• Food Microbiology
• Food Safety
• Microbial Growth at Low Temperatures

Background:

• Recent studies indicate Salmonella can grow at refrigeration temperatures (below 10°C), challenging assumptions about refrigerated food safety.
• Salmonella proliferation has been observed in fresh meats and shell eggs at temperatures as low as 2.0°C and 4.0°C, respectively.
• Inconsistent temperatures in domestic refrigerators exacerbate food safety risks.

Purpose of the Study:

• To assess the behavior of Salmonella in refrigerated foods.
• To evaluate the effectiveness of modified atmosphere packaging (MAP) in controlling Salmonella growth.
• To explore strategies for enhancing the safety of chilled foods.

Main Methods:

• Review of recent scientific reports on Salmonella behavior at chill temperatures.
• Analysis of evidence regarding Salmonella growth in complex media, fresh meats, and shell eggs.
• Examination of the impact of modified atmosphere packaging (MAP) using gaseous mixtures (CO2, N2, O2) on Salmonella.

Main Results:

• Salmonella demonstrates a capacity for growth in refrigerated foods, including fresh meats and shell eggs, within days.
• Modified atmosphere packaging (MAP) effectively inhibits the growth of psychrotrophic spoilage bacteria.
• Current evidence suggests MAP arrests Salmonella growth but does not significantly impact its survival.

Conclusions:

• The safety of refrigerated foods is a concern due to Salmonella's ability to grow at low temperatures.
• Modified atmosphere packaging (MAP) is not a complete solution for eliminating Salmonella in chilled foods.
• Enhancing bacteriostatic factors like pH and NaCl at lower temperatures could improve chilled food safety.