Etiket Arşivleri: shelf life

Shelf Life of Food



• Time during which the food product will: remain safe; retain desired sensory, chemical, physical and microbiological characteristics; comply with any label declaration of nutritional data, when stored under the recommended conditions

• It begins from the time the food is finished processing and packaged.

Factors Affecting Shelf life

Intrinsic Factors               Extrinsic Factors

Water Activity                    Time–temperature profile during processing; pressure in the headspace

pH                                           Temperature control during storage

Redox potential (Eh)        Relative humidity (RH)
Available oxygen                Exposure to light (UV and IR)
Nutrients                               Environmental microbial counts during

Natural microflora and surviving microbiological counts   Composition of atmosphere within packaging.

Use of preservatives in product formulation  Subsequent heat treatment

Shelf life indication on food

• Use by date – foods that have a use by date are generally regarded as unsafe to eat after the designated date because a build-up of bad bacteria may have occurred – even if the food in question still looks and smells good enough to consume.

• It is about safety

• Best Before – It signifies that although the date on the package may have passed, the product is still safe to consume on the proviso the item has been stored according to instructions, while still generally maintaining its colour, texture and flavour.

• It is about quality of food.


1. Accelerated shelf-life testing – The food product is conditioned and stored at elevated temperature and/or humidity and the quality changes of the product are evaluated at a specific sampling rate.

• It can be two to four times faster than the real shelf life study.

Modified Atmosphere Packaging

Modified Atmosphere Packaging


• As the consumers has become more conscious about their health and awareness towards fresh foods has increased, they are willing to pay higher prices for better fresh produce.

• This has led to innovation in packaging technology by preserving the freshness, preventing nutrient losses and processed food consumption.

• MAP provides extended shelf life and improved product presentation in a suitable container.

• Fresh produce has the best quality at harvest which cannot be further improved but shelf life can be extended throughout the post-harvest processing.

• Various factor affect the consumption of fresh produce.
– Mostly this happens due to food borne diseases and its different outbreaks.
– To a lesser extent it is also due to maintenance of fresh produce and off-season produce.
– This issue arises due to the fact that fruits and vegetables being biologically active can spoil due to physical injury, increase in water activity and other metabolic activities like respiration.

• MAP is a technology by which internal atmosphere of perishable products packaging is altered.

• It includes the removal and/or change in the gases for head space environment before final packaging.

• The implementation of MAP has been developed over 90 years (Table 1).

• Fresh carcass meat was exported under controlled atmosphere storage (CAS) in the 1930s.

• Scientist investigated on the use of gas on extending shelf life of fresh meat.

Bisküvi ve Kraker Üretiminde Tritikale Ununun Kullanım Olanakları ( Selda GÜNDOĞDU SERTAKAN )





Bu araştırmada insan yapımı tahıl olarak bilinen tritikalenin bisküvi ve kraker üretimine uygun olup olmadığı incelenmiştir. Çalışmada materyal olarak; Tatlıcak 97 Tritikale çeşidinden elde edilen un ve bisküvilik yumuşak buğday unu ile hazırlanmış %0 (kontrol), %25, %50, %75 ve %100 tritikale içeren un paçalları kullanılmıştır. Paçalların tümünde nem, kül, protein, sedimantasyon, düşme sayısı, yaş gluten miktarı, alkali su tutma kapasitesi, ekstensograf ve farinograf değerleri belirlenmiştir. Hazırlanan un paçallarından, ticari üretim koşullarında pötibör, kepekli bisküvi ve kraker üretilmiş ve üretilen bisküvi ve krakerler bir yıl süre ile depolanarak her üç ayda bir alınan örneklerde peroksit, serbest yağ asitliği, yağ asitleri kompozisyonu, ransimat değeri, tekstür analizleri ve duyusal analizler yapılarak, raf ömrü süresince bisküvilerde meydana gelen kimyasal ve duyusal değişimler izlenmiştir. Unlarda tritikale kullanım oranı artışına paralel olarak düşme sayısı (sn), gecikmeli sedimantasyon (ml), % kül, % protein, % alkali su tutma kapasitesi, % su absorbsiyonu, hamurun uzamaya karşı gösterdiği maksimum direnç (Rmax.), hamurun sabit deformasyon direnci (R ) ve enerji (A) değerleri yükselirken (P<0.01), % nem, % 5 yaş gluten, gelişme süresi (dk), yoğurma toleransı (MTI), yumuşama değeri ve uzama kabiliyeti (E) değerleri düşmüştür (P<0.01). Bisküvi ve kraker örneklerinde en, boy, kalınlık ve ağırlık ölçümleri yapılmıştır. Tritikale unu kullanım oranının artışıyla ters orantılı olarak bisküvi ve krakerlerin boy ve kalınlık değerlerinde düşüş, ağırlıklarında ise artış saptanmıştır. Raf ömrü süresince tüm bisküvi ve krakerlerde raf ömrünün ilerlemesine paralel olarak; nem, peroksit, serbest yağ asitliği, ve tekstür değerleri yükselirken, ransimat ve pH düşmüştür (P<0.01). Bisküvi ve krakerlerin yağ asitleri kompozisyonunun, ağırlıklı olarak Palmitik asit (%40), Oleik asit (%36), Linoleik asitten ( %13) oluştuğu, diğer yağ asitlerinin ise kompozisyonda %5’ten düşük oranlarda yer aldığı saptanmıştır. Raf ömrü süresince çok fazla olmamakla birlikte palmitik asitte düşme, linoleik ve oleik asitte yükselme görülmüştür. Yapılan bu analizler ve duyusal değerlendirmeler sonucunda tritikale ununun; hiçbir proses ve formül değişikliği yapılmadan pötibör üretiminde %50, kraker üretiminde %25, kepekli bisküvi üretiminde ise %100 oranına kadar kullanımının fiziksel, kimyasal ve duyusal kalite kabul edilebilirlik sınırları içerisinde mümkün olabileceği belirlenmiştir. Yıl:2006 Sayfa:192

Anahtar Sözcükler: Tritikale, bisküvi, pötibör, kepekli bisküvi, kraker, duyusal özellikler, raf ömrü.





In this research, it has been analysed whether triticale, recognised as man-made cereal, is suitable to biscuit and cracker production. İn the study; flour blends including % 0 (control), %25, %50, %75 and %100 triticale prepared using Tatlıcak 97 type triticale flour and wheat flour used for producing biscuits have been used. Moisture, ash, protein, sedimantation, falling number, amount of wet gluten, alcaline water absorption capacity, exthensograph, farinograph,values concerning all blends have been determined. Petitbeurres, branny biscuits and crackers have been produced under commercial production conditions and chemical and sensory alterations occuring in biscuits and crackers during their shelf life have been observed and their peroxide, free fatty acid, fatty acid composition, rancimade values have been observed through texture analyses and sensory analyses on samples taken once three months from the products stored for one year. While falling number (sn), delayed sedimantation (ml), ash %, protein %, alcaline water absorption capacity %, water absorbtion %, maximum resistance the dough shows to stretching (Rmax.), static deformation resistance of the dough (R ) and 5 energy (A) values increase (P<0,01); moisture %, wet gluten %, devolepment period (dk), mixing tolerance indeks (MTI), softening value and stretchening capability (E) values decrease (P< 0,01). parallel to increase in use of triticale in flour blends. Width, length, thickness and weight measurements have been done regarding biscuit and cracker samples. Inversely proportional to the increase in use of triticale flour a decrease in the length and width and an increase in the weight of biscuits and crackers have been noticed. Moisture, peroxide, free faty acid and teksture values have increased while rancimade and pH values have decreased during shelf life parallel to the proceeding of shelf life. It has been noticed that fatty acid compositions of biscuits and crackers are mainly consist of palmitic acid (40 %), oleic acid (36 %) and linoleic acid (13 %) while other fatty acids are available in the composition with a value lower than 5%. During the shelf life, although not major, decrease in palmitic acid and increase in oleic acid have been observed. As a result of those analyses and sensory assessments performed it has been determined that use of triticale flour, taking physical, chemical and sensory quality acceptibility into consideration, can be used 50 % in petitbeurre production, 25 % in cracker production and 100 % in branny biscuit production without making any process and formule alterations. Year:2006 Page: 192

Key words: Triticale, Biscuit, Petitbeurre, Branny biscuit, Cracker, Sensory properties, Shelf life.

A Guide to Calculating the Shelf Life of Foods

What is shelf life?

Is the shelf life of food related to food safety?

What are the regulations relating to shelf life?

Who is responsible for calculating a shelf life?

Who influences the shelf life?

Factors influencing the shelf life of a product

What is a shelf life study?

Step by step determination of shelf life ( by the direct method )

What are indirect methods?

What is challenge testing?

Appendix 1: Guidelines for microbiological ( examination of ready-to-eat foods )

Appendix 2: Determination of shelf life of foods ( capable of supporting Listeria monocytogenes )

Appendix 3: Extended shelf life foods and ( Clostridium botulinum )

Appendix 4: Contacts

Appendix 5: Publications

Appendix 6: Further reading

Milk for Liquid

Liquid milk can be delivered to the consumer after various heat treatments: none (raw milk), pasteurized or sterilized, and either packaged or not (although sterilized milk is, of course, always packaged). The properties of liquid milk that require the most attention are safety to the consumer, shelf life, and flavor. Safety is, of course, essential and consumption of raw milk cannot be considered safe. Consequently, the delivery of raw milk is prohibited or severely curtailed in many countries. Likewise, delivering milk that is not packaged may involve health hazards. The relative importance of other quality marks depends on usage.

Milk can be consumed as a beverage, in which case flavor is of paramount importance. Most consumers tend to dislike a cooked flavor and, therefore, low-intensity pasteurization is generally preferred. Others use milk primarily in coffee or tea, in cooking, in baking, etc., where the absence of a cooked flavor is mostly not essential (if not too intense) and shelf life may be the most important quality mark. Consequently, sterilized milk is often favored.