The Final Record: Assignment Food Spoilage – Cause Analysis

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The Final Record: Assignment Food Spoilage


1. Canned apples, strawberry jam

Canned apples /by victor








Causes of spoilage: Using an incorrectly sealed container and Refrigeration problems



2. Chicken jerky

Chicken jerky /by victor













Cause of spoilage: Use of incorrect sealed container (Lock & Lock) and product characteristics

Rationale for Shorter Shelf Life of Chicken Jerky

Chicken jerky often presents a more significant challenge in preservation compared to beef or other red meat jerkies, resulting in a noticeably shorter shelf life. This is primarily due to the composition and structural characteristics of the raw meat:

  1. Lower Fat Content: While often seen as a benefit, lower fat content in chicken means a higher proportion of lean muscle mass and water activity remains after the drying process, even when properly cured. This higher residual water activity creates a more favorable environment for microbial growth and enzymatic activity, which accelerates spoilage compared to fattier meats.

  2. Higher pH (Potential): Depending on the processing method, chicken can sometimes maintain a higher pH than beef. A higher pH level reduces the effectiveness of some antimicrobial treatments and increases the risk of specific bacterial growth (like Salmonella and Clostridium perfringens), even under dehydrated conditions, thereby demanding stricter storage protocols and shorter consumption windows.

  3. Cross-Contamination Risk: The need for extra vigilance during the handling and processing of raw poultry to mitigate risks (such as Salmonella) means that any failure in the heating, drying, or sanitation steps can lead to a more rapid onset of spoilage compared to meats with naturally lower initial bacterial loads.

In summary, while beef jerky benefits from a robust fat barrier and naturally lower moisture content post-dehydration, chicken jerky’s lean composition necessitates superior dehydration and curing techniques to achieve comparable longevity, often making its commercial and homemade shelf life inherently shorter.



3. Lefse, pistachio cookie

Lefse /by victor












Cause of spoilage: Use of incorrect sealed container (Lock & Lock), Refrigeration problems and product characteristics(Cookie)

Rationale for Shorter Shelf Life of Pistachio Cookies

Pistachio cookies often exhibit a reduced shelf life compared to simpler, plain cookies (such as sugar or shortbread cookies). This premature degradation is primarily driven by the chemical and physical characteristics introduced by the nut component:

  1. Susceptibility to Oxidative Rancidity: Pistachios are highly rich in unsaturated fatty acids. While healthy, these fats are chemically unstable and react quickly with oxygen (a process known as oxidation or rancidity). This chemical spoilage manifests as an unpleasant, "off" flavor and odor, significantly shortening the perceived freshness and edibility of the cookie long before the other ingredients might spoil.

  2. Increased Moisture Absorption/Activity: The structure of chopped or ground pistachios within the cookie matrix can act as a wick, increasing the overall surface area and susceptibility of the cookie to absorbing ambient moisture. A slight increase in the cookie's internal water activity (Aw) provides a more favorable condition for mold growth and yeast fermentation, leading to textural changes (sogginess) and microbial spoilage more rapidly than in low-Aw, low-fat cookies.

  3. Presence of Natural Enzymes: Although baking inactivates most enzymes, the oil-rich environment of the pistachio component can still contribute to faster degradation under poor storage conditions (exposure to light or heat), accelerating the overall rate of chemical decomposition.

In summary, the high concentration of easily oxidized unsaturated fats in pistachios makes the cookie highly susceptible to chemical rancidity, while the physical structure of the nuts contributes to faster moisture uptake, demanding stricter environmental control and resulting in an inherently shorter shelf life compared to less complex baked goods.




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